Post-treatment Circulating Tumor Cells Research Articles

Circulating tumor cells: a valuable indicator for locally advanced nasopharyngeal carcinoma.

Advancements in nasopharyngeal carcinoma (NPC) treatment have led to a focus on personalized treatment. Circulating tumor cells (CTCs) are important for liquid biopsies and personalized treatment but are not being fully utilized. This study examined how pre- and post-treatment CTC counts, EMT subtypes, clinical characteristics, and patient prognosis are related in order to support the use of liquid biopsy in managing NPC. This retrospective study included 141 patients with locally advanced NPC. All patients underwent CanPatrol™ CTC detection pre- and post-treatment and were categorized into EMT subtypes: epithelial type, mixed type, and mesenchymal type. This study analyzed CTC enumeration, EMT subtypes, and their associations with clinical characteristics and survival outcomes. The results indicated a positive correlation between the pre-treatment detection rate of CTCs and N stage (P < 0.01), alongside a positive correlation with the TNM clinical stage (P = 0.02). Additionally, the detection rate of mesenchymal CTCs post-treatment is positively associated with the N stage (P = 0.02). The enumeration of CTCs pre- and post-treatment is negatively correlated with prognosis and has statistical significance. Additionally, an investigation into the EMT subtypes of CTCs revealed a significant association between the presence of mesenchymal CTCs pre- and post-treatment and decreased overall survival (OS) (P < 0.05). Furthermore, T stage, N stage, TNM clinical stage, and Epstein-Barr virus (EBV) DNA were also significantly correlated with OS. The study found that mesenchymal CTCs pre- and post-treatment, as well as the number of CTCs, were linked to a poor prognosis.

Abstract PO3-14-10: A single-center prospective cohort study to evaluate circulating tumor cells as a monitoring tool in women with breast cancer treated with neoadjuvant chemotherapy: final results of baseline data

Abstract Background: The presence of liquid biomarkers such as circulating tumor cells (CTCs) among women undergoing neoadjuvant chemotherapy (NAC) for breast cancer may be associated with treatment response and/or an increased risk of recurrence, but limited data is available. Objectives: To detect and enumerate CTCs in blood samples from women with a new diagnosis of non-metastatic breast cancer of any subtype both i) at baseline (prior to commencing NAC), and ii) after completion of NAC and surgery using the Epic Sciences platform. Methods: Women with non-metastatic breast cancer of any subtype who have not yet commenced NAC were included, irrespective of age. Those with a prior history of another invasive cancer (apart from non-melanoma skin cancer identified 5+ years prior to enrollment) were excluded. Blood samples were obtained to measure CTCs prior to commencing NAC, and after completion of NAC and surgery (at least 4 weeks post-operatively). As previously described, CTC identification was based on immunofluorescence analysis using the Epic Sciences platform (Ueno et al 2017). Clinical/pathological data and clinical outcomes were abstracted from patients’ medical records. Associations between CTC detection and clinical/pathologic characteristics were evaluated using Fisher’s exact test for categorical variables and t-test or Wilcoxon rank sum tests for numerical variables. All analyses were performed using the R software package. Results: 50 participants who met eligibility criteria were included; a baseline blood sample was evaluable for CTC detection and enumeration for 47 patients. The median age at breast cancer diagnosis was 52 (29-75). Among them, 18 (38.3%) had HER2+ breast cancer, 17 (36.1%) had hormone receptor (HR)+/HER2- breast cancer and 12 (25.5%) had triple negative breast cancer (TNBC). The majority of patients (91%) received anthracycline and taxane-based NAC. A total of 68 samples were tested for CTC enumeration (5 mL equivalent per sample) including 47 pre-treatment and 21 post-treatment samples. CTCs were detected in 37 (79%) of patients for whom a baseline (pre-NAC) sample was available with a mean of 4.2 (SD 17.0) CTCs/mL and a range of 0 - 115.4 CTCs/mL. Detection of CTCs at baseline was highest among patients with TNBC (n=10/12, 83%), followed by those with HER2+ (n=14/18, 78%) and HR+/HER2- (n=13/17, 76%) breast cancer. CTCs were detected in 43% (n=9/21) of post-treatment samples, with a mean of 1.2 (SD 3.6) CTCs/mL and range of 0 – 16.4 CTCs/mL. Among the 20 patients for whom matched pre- and post-treatment CTC results were available, 16 (80%) had detectable CTCs pre-treatment and 8 (40%) had detectable levels post-NAC and surgery; of the 8 patients with post-treatment CTCs, 4 (50%) had HR+/HER2- breast cancer, 2 had HER2+ (25%) and 2 (25%) had TNBC. Three patients had numerically higher CTC levels after completion of NAC and surgery compared to baseline levels, 2 of whom had HR+/HER2- breast cancer and one of whom had TNBC. To-date, only 8 patients (19% of 43 who have undergone surgery) have achieved a pathological complete response (PCR) to NAC, among whom 3 had matched pre- and post-treatment CTC results available. None of these 3 patients had detectable CTCs post treatment. Conclusions: Approximately 4 in 5 women with non-metastatic breast cancer who undergo NAC have detectable CTCs at baseline (pre-treatment) using the Epic Sciences Platform. Given that CTCs remain detectable in a high proportion (40%) of patients after NAC and surgery, evaluation of CTCs as a potential measure of minimal residual disease warrants further evaluation in this patient population. Citation Format: Rania Chehade, Arushi Jain, Veronika Moravan, Giuseppe Di Caro, Megan Slade, Nadine Hartmann, Rick Wenstrup, Ana Elisa Lohmann, William Tran, Katarzyna Jerzak. A single-center prospective cohort study to evaluate circulating tumor cells as a monitoring tool in women with breast cancer treated with neoadjuvant chemotherapy: final results of baseline data [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-14-10.

The detection of circulating tumor cells indicates poor therapeutic efficacy and prognosis in patients with nonsmall cell lung cancer: A systematic review and meta-analysis.

The efficacy and prognostic value of circulating tumor cells (CTCs) in nonsmall cell lung cancer (NSCLC) are controversial based on the existing research. This systematic review and meta-analysis evaluated the significance of CTCs in NSCLC therapy monitoring and prognosis prediction, supporting their potential as clinical biomarkers. We conducted a comprehensive search of PubMed, Embase, Web of Science, The Cochrane Library, WanFang Data, CNKI, and VIP through September 20, 2023. Inclusion criteria were cohort studies involving NSCLC patients, focusing on peripheral blood CTCs, and assessing outcomes such as pre- and posttreatment CTC rates or levels, progression-free survival (PFS), and overall survival (OS). Two reviewers independently extracted the data and assessed risk of bias using the Newcastle-Ottawa Scale. We utilized Review Manager 5.4.1 for meta-analysis, calculating pooled odds ratios (ORs) for dichotomous outcomes, mean differences for continuous variables and hazard ratios (HRs) for survival data, applying fixed- or random-effects models based on heterogeneity assessed by the I2 statistic. This study was registered in PROSPERO (No. CRD42023450035). Twenty-two eligible studies with a total of 1674 NSCLC patients were included. Meta-analysis results showed that the CTCs-positive rate (OR=0.59, 95% CI 0.45 to 0.77, p=0.0001) and CTCs count (mean difference=-3.10, 95% CI -5.52 to -0.69, p=0.01) were significantly decreased after antitumor treatment. Compared with the CTCs nonreduced group, the CTC-reduced group showed better PFS (HR=1.71, 95% CI 1.35 to 2.17, p<0.00001) and OS (HR=1.50, 95% CI 1.21 to 1.86, p=0.0003) after treatment. PFS and OS in CTC-positive groups were lower than those in the CTCs-negative group pretreatment (HR=2.49, 95% CI 1.78 to 3.47, p<0.00001; HR=1.80, 95% CI 1.29 to 2.52, p=0.0006) and posttreatment (HR=3.36, 95% CI 2.12 to 5.33, p<0.00001; HR=3.31, 95% CI 1.75 to 6.27, p=0.0002). CTCs can be used as a biomarker to monitor NSCLC efficacy, predict prognosis and guide follow-up treatment.

Abstract P6-01-17: A single-center prospective cohort study to evaluate circulating tumor cells as a monitoring tool in women with breast cancer treated with neoadjuvant chemotherapy

Abstract Background The presence of circulating tumor cells (CTCs) among women before and/or after completion of neoadjuvant chemotherapy (NAC) for breast cancer may be associated with an increased risk of recurrence, but limited data is available. Objectives To use the Epic Sciences platform to detect and enumerate CTCs in blood samples from women with a new diagnosis of non-metastatic breast cancer of any subtype both i) prior to commencing NAC, and ii) after completion of NAC and surgery. Methods Inclusion criteria included women of any age with non-metastatic breast cancer of any subtype who have not yet commenced NAC. Those diagnosed with prior invasive cancer at any site (apart from non-melanoma skin cancer diagnosed more than five years prior to enrollment) were excluded. Blood samples were obtained to measure CTCs prior to NAC and after NAC and surgery, respectively. CTC identification was based on immunofluorescence analysis using Epic Sciences platform as previously described (Ueno et al 2017). The presence of CTCs was correlated with clinical/pathological data and treatment response, which were abstracted from patients’ medical records. The association between the presence of CTCs and clinical/pathologic characteristics was tested using Fisher’s exact test for categorical variables and t-test or Wilcoxon rank sum tests for numerical variables. All analyses were performed using the R software package. An ad-hoc preliminary analysis was conducted among the first 34 of 50 participants. Results 41 patients (out of an intended 50) have been recruited to-date. 34 participants have a pre- and/or post-treatment CTC measurement available, but 1 was excluded because it was identified to have metastatic disease shortly after enrollment. Among 33 evaluable patients without metastatic disease, 6 (19%) had triple negative breast cancer (TNBC), 13 (39%) had HER2+ and 13 (39%) had hormone receptor (HR)+/HER2- breast cancer. Most (94%) received anthracycline and taxane-based NAC. The median age of breast cancer diagnosis was 50 (29-75). A total of 53 samples were tested for CTC enumeration (5 mL per sample) including 33 pre-treatment and 20 post-treatment samples. CTCs were detected in 32 samples (n=32/53, 60%), including 24 pre-NAC (n=24/33, 73%) with a median of 0.9 CTCs per mL (0.2-19) and 8 post-NAC and surgery (n= 8/20, 40%) with a median of 0.6 CTCs per mL (0.3-3.3). Among the 24 patients (73%) who had detectable CTCs pre-NAC, 10 had HR+/HER2- (41.7%), 9 had HER2+ (37.5%) and 4 (16.7%) had triple negative disease. Among the 20 patients for whom matched pre- and post-treatment CTC results were available, 16 (80%) had detectable CTCs pre-treatment and 8 (40%) had detectable levels post-NAC and surgery. Among the 8 patients (40%) for whom CTCs were detectable post NAC and surgery, 4 (50%) had HR+/HER2-, 2 had HER2+ (25%) and 2 (25%) had triple negative disease. 3 of these patients had numerically higher CTC levels after completion of NAC and surgery compared to pre-NAC levels, 2 of whom had HR+/HER2- breast cancer and one of whom had TNBC. A total of 7 of 33 patients achieved a pathological complete response (PCR) to NAC, among whom 3 had matched pre- and post-treatment CTC results available; none of these 3 patients had detectable CTCs post-treatment. Conclusions Approximately 3 in 4 women with non-metastatic breast cancer who undergo NAC have detectable CTCs pre-treatment using the Epic Sciences Platform. Of 20 patients with matched pre-/post-treatment results, a high proportion (40%) have persistently detectable CTCs. Hence, CTCs may represent an additional measure of minimal residual disease for patients undergoing NAC for breast cancer. Citation Format: Rania chehade, Arushi Jain, Veronika Moravan, Giuseppe Di Caro, Amanda Anderson, Megan M. Slade, Rick Wenstrup, Ana Elisa Lohmann, William Tran, Katarzyna Jerzak. A single-center prospective cohort study to evaluate circulating tumor cells as a monitoring tool in women with breast cancer treated with neoadjuvant chemotherapy [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-01-17.

Circulating tumor cells as a biomarker for precise management in lung cancer.

e21018 Background: Circulating tumor cells (CTCs) have potential utility in various clinical application for cancer management. In this study, we evaluated whether circulating tumor cells (CTCs) provide early diagnostic information and/or precisely indication of patient response to chemotherapy. Methods: 56 patients with newly diagnosed lung cancer, 42 patients with nonmalignant pulmonary disease and 27 healthy controls were enrolled in this study. CTCs were measured at baseline in all eligible subjects and after two cycles of chemotherapy in 25 advanced lung cancer patients, with a strategy of negative enrichment combined with immunostaining-fluorescence in situ hybridization (imFISH). The receiver operating characteristic (ROC) curve was plotted to determine the sensitivity and specificity of the CTC detection for diagnosis. Kaplan-Meier curve and two-sided log-rank test were used for univariate survival analyses. Results: The number of CTCs was significantly increased in lung cancer patients, compared with benign lung disease patients and healthy controls. And it reached 87.5% sensitivity and 95.7% specificity at a cutoff value of 2 cells/3.2ml (AUC = 0.975, 95%CI, 0.953-0.998, p＜0.001).Moreover, the sensitivity of CTCs was much higher than individual or the combination of serum tumor markers, especially in the early detection of lung cancer. Twenty-five advanced lung cancer patients were subsequently followed for an average of 18.2 months (range 6-36 months) ， during which all patients experienced disease progression, and 16 patients died. A change in CTC count after two cycles of chemotherapy was highly predictive for PFS (13.5 v 8.5 months; p = 0.025) and OS (27.6 v 16.8 months; p = 0.009) in favor of a reduction in CTC number compared with an increase. Interestingly, among the patients whose post-treatment computed tomography(CT) results indicated stable disease(SD), PFS (14.0 v 8.7months; p = 0.033) and OS(25.8 v 15.9 months; p = 0.018) in patients whose CTC number decreased after two cycles of treatment were still significantly longer than those whose post-treatment CTCs number increased or unchanged. Conclusions: CTCs may act as precise biomarker for early detection and therapy monitoring that could compensate for imaging.

Value of Early Circulating Tumor Cells Dynamics to Estimate Docetaxel Benefit in Metastatic Castration-Resistant Prostate Cancer (mCRPC) Patients.

Simple SummaryThe prognostic role of CTC enumeration in mCRPC patients has been established in several studies, demonstrating a higher prognostic performance than post-treatment changes in PSA levels in patients treated with AR signaling inhibitors, but not taxanes. We carried out a pooled analysis of two prospective studies in mCRPC patients treated with docetaxel. The results of this study showed a greater ability of early changes in circulating tumor cells (CTCs) compared to PSA response endpoints to predict overall survival in metastatic castration-resistant prostate cancer (mCRPC) patients treated with docetaxel. These results encourage the clinical usefulness of CTC enumeration to determine the outcome of mCRPC patients.Circulating tumor cell (CTC) enumeration and changes following treatment have been demonstrated to be superior to PSA response in determining mCRPC outcome in patients receiving AR signaling inhibitors but not taxanes. We carried out a pooled analysis of two prospective studies in mCRPC patients treated with docetaxel. CTCs were measured at baseline and 3–6 weeks post treatment initiation. Cox regression models were constructed to compare 6-month radiographical progression-free survival (rPFS), CTCs and PSA changes predicting outcome. Among the subjects, 80 and 52 patients had evaluable baseline and post-treatment CTC counts, respectively. A significant association of higher baseline CTC count with worse overall survival (OS), PFS and time to PSA progression (TTPP) was observed. While CTC response at 3–6 weeks (CTC conversion (from ≥5 to <5 CTCs), CTC30 (≥30% decline in CTC) or CTC0 (decline to 0 CTC)) and 6-month rPFS were significantly associated with OS (all p < 0.005), the association was not significant for PSA30 or PSA50 response. CTC and PSA response were discordant in over 50% of cases, with outcome driven by CTC response in these patients. The c-index values for OS were superior for early CTC changes compared to PSA response endpoints, and similar to 6-month rPFS. Early CTC declines were good predictors of improved outcomes in mCRPC patients treated with docetaxel in this small study, offering a superior and/or earlier estimation of docetaxel benefit in comparison to PSA or rPFS that merits further confirmation in larger studies.

Assessment of the Circulating Tumor Cells and Microsatellite Instability in Colorectal Cancer Patients: Prognostic and Diagnostic Value.

BackgroundMicrosatellite instability (MSI) and circulating tumor cells (CTCs) play important roles in the diagnosis, prognosis and management of colorectal cancer (CRC) patients.MethodsCTCs and MSI were assessed in the blood and representative tumor tissues of 100 CRC patients by flow cytometry (FCM) and PCR amplification. The data were correlated to relevant clinicopathological features of the patients, progression-free survival (PFS) and overall survival (OS) rates.ResultsMSI-high was detected in 44 (44.0%) patients, MSI-low in 37 (37%), and microsatellite stable (MSS) in 19 (19.0%) patients (P=0.007). The baseline CTCs count (<4 cells/7mL blood) was reported in 39% of the patients, and CTCs ≥4 cells/7mL blood in 61% of the patients (P=0.028). Improved PFS and OS rates were associated significantly with MSI-high (P<0.001), decreased CTC levels during the course of treatment (P<0.001) and post-treatment CTCs (P=0.008). There was no significant association between MSI-high and PFS or OS in early-stage patients (P=0.187 and P=0.187; respectively); however, it was associated significantly with better PFS and OS in late-stage patients (P<0.001). Multivariate analysis showed that only a change in serial CTC levels is considered an independent prognostic factor for OS (P<0.012). Post-treatment CTCs level, serial CTCs level changes during the course of treatment, lymph nodes and distant metastasis were independent prognostic factors for PFS (P<0.001, P= 0.047, P=0.001 and P<0.001; respectively).ConclusionMSI and CTCs could be used as accurate, reliable and sensitive diagnostic and prognostic biomarkers for CRC patients’ survival rates and outcomes.

Baseline and post-treatment circulating tumor cell (CTC) counts with prostate-specific membrane antigen (PSMA)-targeted radionuclide therapy (TRT) in men with metastatic castration-resistant prostate cancer (mCRPC).

158 Background: CTC counts are an independent prognostic factor in men with mCRPC; certain changes following treatment (conversion from detectable to undetectable or unfavorable to favorable) are associated with improved overall survival. Most PSMA-TRT efficacy data have focused on PSA or imaging changes. Here, we describe baseline and post-treatment CTC counts from subjects receiving PSMA-TRT. Methods: Men with mCRPC treated on prospective clinical trials of PSMA-TRT and with available CTC counts (CellSearch) were included in our analysis. Depending upon the era of the trial, post-treatment counts were performed at 4-6 (initial era) or 12 weeks (recent era) after a single cycle of PSMA-TRT (individual trial data reported elsewhere). We describe CTC counts at baseline and compare pre-treatment counts to those after PSMA-TRT. Results: 116 men treated with PSMA-TRT had baseline CTC count (90 with both pre- and post-treatment CTC). Forty-four patients (37.9%) received 177Lu-J951, 46 (39.7%) received 177Lu-PSMA-617, and 26 (22.4%) received 225Ac-J591. Median age was 71.5. Fifty-eight patients (50%) had previously received taxane chemotherapy, median PSA was 82.98 ng/mL, and 66 (56.9%) were in the high-risk Halabi (CALGB) prognostic group. Eighty-nine out of one hundred sixteen (76.7%) had detectable baseline CTC and 58/116 (50%) had unfavorable baseline CTC count. Forty-nine out of seventy (70%) had post-treatment CTC count decline, 23/70 (32.9%) converted from detectable to undetectable, and 17/47 (36.2%) converted from unfavorable to favorable. CTC changes stratified by type of PSMA-TRT are reported in the table. Conclusions: This is the largest analysis of CTC changes in patients who have received PSMA-TRT. In addition to PSA changes and other previously reported outcomes, even when low doses of radionuclide therapy as part of dose-escalation studies are included, the majority with detectable CTC counts have post-treatment CTC count decline. A significant portion of patients experience favorable CTC changes. [Table: see text]

Pilot study of anti-prostate-specific membrane antigen (PSMA) antibody J591 for men with metastatic castration-resistant prostate cancer (mCRPC) and unfavorable circulating tumor cell (CTC) count.

120 Background: Elevated CTC counts are associated with a poor prognosis in men with mCRPC. PSMA targeted radionuclide therapy has been associated with decline in CTC count, but it remains unclear whether this effect results from radionuclide-induced cytotoxicity. J591 was engineered to have antibody-dependent cytotoxicity. A subset of patients was observed to have CTC count decline following imaging with 111In-J591, so a prospective study was launched to test the hypothesis that “naked” J591 leads to CTC count decline. Methods: In a Simon 2-stage dose de-escalation study, men with progressive mCRPC and unfavorable CTC count (CellSearch &gt; 4) received a single dose of J591. Initial dose cohort 300 mg with de-escalation to 20 mg. CTC count was re-assessed 4, 8, and 12 weeks following therapy along with PSA and standard imaging. An optional PSMA PET was included prior to treatment. The primary endpoint was proportion of subjects with conversion to favorable CTC count ( &lt; 5 CTCs/7.5 mL blood) and/or &gt; 30% decline from baseline within 12 weeks post-treatment. Results: 10 men were enrolled, 9 of whom were evaluable (1 died of progressive mCRPC prior to post-treatment CTC count). Median age was 71.5 years (range 60-81), 78% had prior chemo, ECOG PS 1 in 45% and 2 in 55%. 7 of 9 (78%) evaluable subjects were Halabi CALGB prognostic poor risk category and 2 (22%) intermediate. 6 of 9 had pre-treatment PSMA PET/CT (three 89Zr-J591 and three 68Ga-PSMA11). Though not required, all scans showed &gt; 1 lesion with SUVmax &gt; liver SUV (range 9.12-70.15). 2 of 6 in the 300 mg cohort had CTC count decline; 1 of 6 converted to favorable count (9 to 0 with decrease of 35 to 12 in other). 3 were treated with 20 mg; 1 had CTC count decline of 316 to 112, but 0 converted to favorable count. Across both cohorts, 3 of 9 had a CTC count decline at any point in time, ranging from 65-100% decline. With the pre-specified 2-stage design, enrollment was halted for futility based upon the primary endpoint of 12-week CTC count. PSA values post-treatment increased in 8 (89%) patients and remained unchanged in 1 (11%) patient. Conclusions: Single-agent anti-PSMA antibody J591 may lead to decline in CTC count, though the study did not meet its primary endpoint. A combination or maintenance approach might be preferable and is worthy of exploration.

Predicting Circulating Tumor Cells from Intratumoral Radiomic Heterogeneity of 18F-FDG-PET/CT in Early Stage Non-Small Cell Lung Cancer Treated with Stereotactic Body Radiation Therapy

Patients with early stage non-small cell lung cancer (ES-NSCLC) treated with stereotactic body radiation therapy (SBRT) have excellent local control rates although they have a relatively high rate of regional and distant recurrences. Recently, patients with elevated pre-treatment (pre-RT) circulating tumor cells (CTCs) or persistently detectable post-treatment (post-RT) CTCs were found to have significantly increased risk of regional and distant recurrence outside the treatment volume. Knowledge about radiomics biomarkers associated with CTCs may have additional value in predicting these recurrences. This study aims to evaluate the predictability of radiomic phenotypes of intratumoral heterogeneity for pre- and post-RT CTCs in ES-NSCLC patients treated with SBRT. A total of 56 patients with stage I NSCLC treated with SBRT underwent 18F-FDG-PET/CT imaging pre-SBRT and post-SBRT (median, 5 months; range, 3 to 10 months). For each patient, CTCs were assessed via a telomerase-based assay before (“pre”) and within 3 months after SBRT (“post”), and dichotomized at 5 and 1.3 CTCs/mL. Pre-RT, post-RT and delta radiomics features were extracted from the gross tumor volume of the original, wavelet-filtered, Laplacian of Gaussian-filtered PET/CT images, each of which included 1,562 CT and 1,548 PET radiomics features that consisted of shape, first-order, second-order, higher-order local gray-level statistics and global texture features. CT and PET radiomics features were considered different omics data types. Two (CT and PET)-block radiomics-based data integration analysis for biomarker discovery using latent components (DIABLO) was performed to seek for common information between CT and PET radiomics data types through feature selection, while discriminating CTC levels. ROC AUC value and 20-repeated 5-fold cross-validation (CV) were used to evaluate the prediction performance of the DIABLO models. CV prediction scores between one class vs the other were compared using the Wilcoxon rank sum test. For predicting pre-SBRT CTCs, a pre-SBRT radiomics-derived DIABLO model showed the CV AUC of 0.841 (p = 0.018) with two global texture features from wavelet-filtered CT and PET. For predicting post-RT CTCs, post-RT and delta radiomics-derived DIABLO models showed the CV AUCs of 0.794 (p = 0.018) with four global texture features from wavelet-filtered CT and original PET, and 0.799 (p = 0.013) with three first-order features from wavelet-filtered PET and a single second-order texture feature from wavelet-filtered CT. Radiomics signatures that reflect intratumoral anatomic and metabolic heterogeneities derived by maximizing common information between CT and PET may reveal surrogate biomarkers for pre-RT and post-RT CTCs.

First-Line Doublet Chemotherapy for Metastatic Triple-Negative Breast Cancer: Circulating Tumor Cell Analysis of the tnAcity Trial.

PurposeCirculating tumor cells (CTCs) are prognostic biomarkers in metastatic breast cancer, but their role in predicting treatment outcomes in metastatic triple-negative breast cancer (mTNBC) is less clear. The tnAcity trial demonstrated a significant progression-free survival (PFS) benefit with nab-paclitaxel (nab-P)/carboplatin (C) over nab-P/gemcitabine (G) or G/C in patients with mTNBC. We assessed the correlation between CTC dynamics and clinical benefit in all patients and by treatment arm.MethodsCTC enumeration, performed using CELLSEARCH technology (Menarini Silicon Biosystems, Huntingdon Valley, PA, USA), was a prespecified exploratory endpoint in the tnAcity trial. Patients with TNBC were categorized based on pre- and post-treatment CTC levels: Group 1 (+ + +; elevated CTCs at baseline and postbaseline), Group 2 (+ ± ±; CTCs elevated at baseline and cleared postbaseline [cycle 3 and/or cycle 5]), or Group 3 (−; no CTCs detected at baseline). The baseline cutoff was ≥1 CTC/7.5 mL for the main analysis; cutoffs of ≥2 and ≥5 CTCs were used for supporting analyses.ResultsThe main analysis included 126 patients (Group 1, n = 24; Group 2, n = 54; and Group 3, n = 48). The median PFS was longer in Group 2 vs Group 1 (8.5 vs 4.7 months; HR, 0.30 [95% CI, 0.17–0.54]). These results were supported by the ≥2- and ≥5-CTC cutoff analyses. The median overall survival rates were 17.8, 16.0, and 9.8 months in Groups 2, 3, and 1, respectively. The overall response rates were 79.6%, 43.8%, and 29.2%, respectively. A numerically higher percentage of patients had CTC clearance during nab-P/C treatment vs nab-P/G or G/C.ConclusionEfficacy outcomes trended positively with chemotherapy-induced elimination of CTCs, suggesting that CTC clearance may predict the chemosensitivity of mTNBC tumors.Trial registrationEudraCT Number: 2013-000113-20; ClinicalTrials.gov number: NCT01881230.

The Promise of Circulating Tumor Cells in Metastatic CRPC

The Promise of Circulating Tumor Cells in Metastatic CRPC

High Number of Circulating Tumor Cells Predicts Poor Survival of Cutaneous Melanoma Patients in China.

BackgroundMelanoma is an aggressive cancer with complex etiology and poor prognosis. Surgical resection is still the primary treatment of melanoma, but shows limited efficacy in late-stage patients. Additionally, reliable prognostic markers of skin melanoma patients are still lacking. Circulating tumor cells (CTCs) have shown promise in predicting prognosis of multiple cancers.Evaluating the prognostic value of CTC number in melanoma patients.Material/MethodsCTCs were isolated by immunomagnetic capture from 7.5-mL samples of blood from 100 patients with cutaneous melanoma. Baseline CTC number (pre-treatment) and post-treatment CTC number were measured. Baseline CTC number and CTC number alteration were correlated with clinicopathological features and survival.ResultsForty-three (43%) patients had more than 6 CTCs, whereas 57 (57%) had 6 cells or less. High baseline CTC count was associated with deep local invasion, lymph node metastasis, and distance metastasis, with P value of 0.003, 0.047, and 0.034, respectively. High baseline CTC count was also correlated with short overall survival time and was considered as an independent prognostic factor (P value=0.012, hazard ratio=2.262). CTC cell alteration was associated with progression-free survival and disease-specific survival (with P values of 0.012 and 0.009, respectively).ConclusionsBaseline CTC count was correlated with adverse pathological features and was predictive of survival in melanoma patients. Alteration of CTC count before and after treatment was an indicator of therapy response and prognosis. Measuring the baseline and post-treatment CTC counts is a powerful tool in monitoring melanoma progression, drug response, and survival.

Abstract 1735: Assessing circulating tumor cells with a nanotechnology-based capture system as a novel biomarker for treatment response and surveillance in patients with oligometastatic solid tumors

Abstract Purpose: To prospectively evaluate changes in circulating tumor cells (CTCs) following definitive treatment in patients with oligometastatic solid tumors using a novel nanotechnology-based biomimetric platform. Experiment Procedures: Patients with biopsy proven oligometastatic disease with up to three lesions were eligible if all sites of disease were treated with definitive therapy. Definitive therapy could include fractionated 3D conformal radiation, SBRT, IORT, surgical metastatectomy, and ablative procedures including microwave ablation. Patients initially presenting with oligometastatic disease were eligible if they had less than 3 lesions including the primary tumor. At least one lesion had to be treated with radiation. CTCs were enumerated from whole blood using the Onco-Sense CTC capture system which utilizes E-selectin and dendrimers functionalized with three cancer-specific antibodies (aEpCAM, aHER-2, aEGFR). Whole blood was collected from patients prior to starting treatment (baseline), mid-treatment, end of treatment, within 12 weeks of finishing treatment, and then every 3 months in follow up. We then assessed changes in CTCs with treatment and looked for associations between baseline CTCs, changes during treatment, and post-treatment changes with clinical outcomes. Results: We have currently enrolled 24 patients. The majority of patients (20) had a single site of disease treated with radiosurgery. Sites of metastasis include bone, lung, and lymph nodes. Primary histologies include lung, breast, melanoma, prostate, RCC, colorectal cancer, and SCC of the head and neck. CTCs were detected in 100% of patients at baseline and decreased with treatment from a mean of 45 CTCs/mL pretreatment (range 3-99) to 14 CTCs/mL post-treatment (range 3-59). Post-treatment CTCs are available for 14 patients with a median follow up of 10.3 months. Ten of 14 patients remain clinically NED and post-treatment CTCs are lower than baseline in 13/14 of these patients. There have been 4 clinical failures and CTCs increased with or before radiographic progression in all 4 patients. Three of the failures occurred at least 3 months after initial complete responses to treatment and CTCs increased by a median 3.4-fold over post-treatment levels in these patients. One patient progressed before the first post-treatment follow up and CTCs increased from 7 to 22 CTCs/mL from baseline to post-treatment. Conclusions: We showed here that we could enumerate CTCs in 100% of patients with oligometastatic disease using a novel CTC capture system. CTCs decreased with treatment and all clinical failures were preceded by significant rises in CTCs. Our preliminary data suggest that enumeration of CTCs by Onco-Sense may provide a novel biomarker for assessing treatment response and/or post-treatment surveillance for patients with oligometastatic solid tumors. Note: This abstract was not presented at the meeting. Citation Format: Joseph M. Caster, Kyle Wang, Bhisham Chera, Sin-Jun Park, Seungpyo Hong, Andrew Z. Wang. Assessing circulating tumor cells with a nanotechnology-based capture system as a novel biomarker for treatment response and surveillance in patients with oligometastatic solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1735. doi:10.1158/1538-7445.AM2017-1735

Randomized, Noncomparative, Phase II Trial of Early Switch From Docetaxel to Cabazitaxel or Vice Versa, With Integrated Biomarker Analysis, in Men With Chemotherapy-Naïve, Metastatic, Castration-Resistant Prostate Cancer

Purpose The TAXYNERGY trial ( ClinicalTrials.gov identifier: NCT01718353) evaluated clinical benefit from early taxane switch and circulating tumor cell (CTC) biomarkers to interrogate mechanisms of sensitivity or resistance to taxanes in men with chemotherapy-naïve, metastatic, castration-resistant prostate cancer. Patients and Methods Patients were randomly assigned 2:1 to docetaxel or cabazitaxel. Men who did not achieve ≥ 30% prostate-specific antigen (PSA) decline by cycle 4 (C4) switched taxane. The primary clinical endpoint was confirmed ≥ 50% PSA decline versus historical control (TAX327). The primary biomarker endpoint was analysis of post-treatment CTCs to confirm the hypothesis that clinical response was associated with taxane drug-target engagement, evidenced by decreased percent androgen receptor nuclear localization (%ARNL) and increased microtubule bundling. Results Sixty-three patients were randomly assigned to docetaxel (n = 41) or cabazitaxel (n = 22); 44.4% received prior potent androgen receptor-targeted therapy. Overall, 35 patients (55.6%) had confirmed ≥ 50% PSA responses, exceeding the historical control rate of 45.4% (TAX327). Of 61 treated patients, 33 (54.1%) had ≥ 30% PSA declines by C4 and did not switch taxane, 15 patients (24.6%) who did not achieve ≥ 30% PSA declines by C4 switched taxane, and 13 patients (21.3%) discontinued therapy before or at C4. Of patients switching taxane, 46.7% subsequently achieved ≥ 50% PSA decrease. In 26 CTC-evaluable patients, taxane-induced decrease in %ARNL (cycle 1 day 1 v cycle 1 day 8) was associated with a higher rate of ≥ 50% PSA decrease at C4 ( P = .009). Median composite progression-free survival was 9.1 months (95% CI, 4.9 to 11.7 months); median overall survival was not reached at 14 months. Common grade 3 or 4 adverse events included fatigue (13.1%) and febrile neutropenia (11.5%). Conclusion The early taxane switch strategy was associated with improved PSA response rates versus TAX327. Taxane-induced shifts in %ARNL may serve as an early biomarker of clinical benefit in patients treated with taxanes.

Clinical outcome of metastatic castration-resistant prostate cancer (mCRPC) patients (pts) with a post-treatment circulating tumor cell (CTC) of 0 vs CTC &gt; 0: Post hoc analysis of COU-AA-301.

5015 Background: Assessment of radiographic response by RECIST in the majority of mCRPC pts is limited by the lack of measurable disease. Changes in CTC counts (CTCs) enumerated using Veridex CellSearch from unfavorable at baseline (BL [≥ 5 cells/7.5 mL]) to favorable (≤ 4) are prognostic for survival, and the test is FDA cleared as an aid in the monitoring of metastatic PC. The CTC cutpoint of ≥ 5 excludes many pts from response assessment. Examining CTCs alone and in combination with other biomarkers as a potential surrogate for clinical benefit was a secondary objective of COU-AA-301, a phase 3 trial of abiraterone acetate + prednisone vs prednisone alone in mCRPC. Methods: Pts from both treatment (tmt) groups with BL CTC &gt; 0 were combined to assess CTC = 0 as a response criterion. Association between CTC response, defined as BL CTC &gt; 0 and post-BL CTC = 0, and clinical outcomes was assessed. CTCs were determined at BL and 4, 8, and 12 wks. Pts with BL CTC &gt; 0 and missing post-tmt CTCs were considered nonresponders. Radiographic response was first assessed at Wk 12. Overall survival (OS) was estimated using the Kaplan-Meier method. Results: Among739 pts with BL CTC &gt; 0, 141 had measurable disease. At Wk 12, 19% (141/739) of pts were CTC responders and 81% (598/739) were CTC nonresponders. Among CTC responders, 74% (104/141) had stable disease or better by RECIST; 26% (37/141) were either not evaluable or had disease progression by RECIST. Median OS was 23.8 and 10.0 mos for CTC responders (n = 141) and nonresponders (n = 598), respectively. Among pts with liver and/or lung metastases, 86% (24/28) of CTC responders at Wk 12 had stable disease or better by RECIST; 14% (4/28) had disease progression by RECIST. Median OS was 19.9 and 7.1 mos for CTC responders (n = 28) and nonresponders (n = 127), respectively. Similar results were observed in Wk 8 CTC responders. Conclusions: For mCRPC pts with BL CTC &gt; 0, CTC response on tmt (CTC = 0) is associated with longer survival and could be considered a response criterion. Additional analysis is required to fully characterize the relationship between CTC = 0 and objective response by RECIST in pts with measurable disease. Clinical trial information: NCT00638690.

Prospective characterization of circulating tumor cells using a nanotechnology-based capture system in oligometastatic patients undergoing definitive radiation therapy.

11533 Background: Circulating tumor cells (CTCs) can provide prognostic information in select patients with advanced cancers. We have developed a sensitive and specific CTC capture system (Oncosensor) which may predict clinical outcomes in patients undergoing definitive radiation for head and neck cancers. There is increasing interest in utilizing potentially curative metastasis-directed therapy for patients with oligometastatic solid-tumor malignancies. There is currently no biomarker to predict the success of this approach in most patients. The purpose of this prospective study is to investigate the potential utility of CTCs as a predictive biomarker for patients with oligometastatic cancer undergoing potentially curative therapy. Methods: Eligible patients had a metastatic solid-tumor malignancy with 3 or fewer metastases. All sites of disease were treated with definitive radiation or surgery. Concurrent chemotherapy was allowed. Peripheral blood (7 ml) was collected prior to starting, first week, mid-point, end RT, and every 4 to 12 weeks post RT. CTCs were quantified using the Oncosensor platform. We then assessed correlations between CTCs (baseline, end treatment, and changes during treatment) and clinical outcomes using multivariate analysis. Results: Baseline CTCs were detected in 20/20 enrolled patients with a mean baseline of 32/ml which decreased to a mean of 14/ml at the end of treatment. There was no association between pretreatment CTCs and clinical outcomes (p = 0.81). There was a significant association between post-RT CTCs and PFS (p = 0.039, HR 1.07 per CTC). Our data also suggest that post-treatment CTC monitoring may be able to detect early disease recurrence. Among the 4 patients with documented clinical failures and post-treatment CTC monitoring, all 4 had increases in CTCs with or prior to clinical or radiographic disease progression, with 1.6 to 7.3 fold increase at the time of progression compared to the prior time point. Conclusions: Our pilot data suggest CTCs may provide a predictive biomarker for patients with oligometastatic disease and could potentially provide a novel marker of disease recurrence.

Prognostic and predictive value of circulating tumor cells and CXCR4 expression as biomarkers for a CXCR4 peptide antagonist in combination with carboplatin-etoposide in small cell lung cancer: exploratory analysis of a phase II study

SummaryBackground Circulating tumor cells (CTCs) and chemokine (C-X-C motif) receptor 4 (CXCR4) expression in CTCs and tumor tissue were evaluated as prognostic or predictive markers of CXCR4 peptide antagonist LY2510924 plus carboplatin-etoposide (CE) versus CE in extensive-stage disease small cell lung cancer (ED-SCLC). Methods This exploratory analysis of a phase II study evaluated CXCR4 expression in baseline tumor tissue and peripheral blood CTCs and in post-treatment CTCs. Optimum cutoff values were determined for CTC counts and CXCR4 expression in tumors and CTCs as predictors of survival outcome. Kaplan-Meier estimates and hazard ratios were used to determine biomarker prognostic and predictive values. Results There was weak positive correlation at baseline between CXCR4 expression in tumor tissue and CTCs. Optimum cutoff values were H-score ≥ 210 for CXCR4+ tumor, ≥7% CTCs with CXCR4 expression (CXCR4+ CTCs), and ≥6 CTCs/7.5 mL blood. Baseline H-score for CXCR4+ tumor was not prognostic of progression-free survival (PFS) or overall survival (OS). Baseline CXCR4+ CTCs ≥7% was prognostic of shorter PFS. CTCs ≥6 at baseline and cycle 2, day 1 were prognostic of shorter PFS and OS. None of the biomarkers at their respective optimum cutoffs was predictive of treatment response of LY2510924 plus CE versus CE. Conclusions In patients with ED-SCLC, baseline CXCR4 expression in tumor tissue was not prognostic of survival or predictive of LY2510924 treatment response. Baseline CXCR4+ CTCs ≥7% was prognostic of shorter PFS. CTC count ≥6 at baseline and after 1 cycle of treatment were prognostic of shorter PFS and OS.

Decline in Circulating Tumor Cell Count and Treatment Outcome in Advanced Prostate Cancer

BackgroundTreatment response biomarkers are urgently needed for castration-resistant prostate cancer (CRPC). Baseline and post-treatment circulating tumor cell (CTC) counts of ≥5 cells/7.5ml are associated with poor CRPC outcome. ObjectiveTo determine the value of a ≥30% CTC decline as a treatment response indicator. Design, setting, and participantsWe identified patients with a baseline CTC count ≥5 cells/7.5ml and evaluable post-treatment CTC counts in two prospective trials. InterventionPatients were treated in the COU-AA-301 (abiraterone after chemotherapy) and IMMC-38 (chemotherapy) trials. Outcome measures and statistical analysisThe association between a ≥30% CTC decline after treatment and survival was evaluated using univariable and multivariable Cox regression models at three landmark time points (4, 8, and 12 wk). Model performance was evaluated by calculating the area under the receiver operating characteristic curve (AUC) and c-indices. ResultsOverall 486 patients (122 in IMMC-38 and 364 in COU-AA-301) had a CTC count ≥5 cells/7.5ml at baseline, with 440, 380, and 351 patients evaluable at 4, 8, and 12 wk, respectively. A 30% CTC decline was associated with increased survival at 4 wk (hazard ratio [HR] 0.45, 95% confidence interval [CI] 0.36–0.56; p<0.001), 8 wk (HR 0.41, 95% CI 0.33–0.53; p<0.001), and 12 wk (HR 0.39, 95% CI 0.3–0.5; p<0.001) in univariable and multivariable analyses. Stable CTC count (<30% fall or <30% increase) was not associated with a survival benefit when compared with increased CTC count. The association between a 30% CTC decline after treatment and survival was independent of baseline CTC count. CTC declines significantly improved the AUC at all time-points. Finally, in the COU-AA-301 trial, patients with CTC ≥5 cells/7.5ml and a 30% CTC decline had similar overall survival in both arms. ConclusionsA 30% CTC decline after treatment from an initial count ≥5 cells/7.5ml is independently associated with CRPC overall survival following abiraterone and chemotherapy, improving the performance of a multivariable model as early as 4 wk after treatment. This potential surrogate must now be prospectively evaluated. Patient summaryCirculating tumor cells (CTCs) are cancer cells that can be detected in the blood of prostate cancer patients. We analyzed changes in CTCs after treatment with abiraterone and chemotherapy in two large clinical trials, and found that patients who have a decline in CTC count have a better survival outcome.

Abstract P1-13-02: Early change in topoisomerase 1 (Top1) positive circulating tumor cells (CTCs) is associated with overall survival (OS) in patients with advanced breast cancer after treatment with etirinotecan pegol

Abstract Background: Etirinotecan pegol (EP) is a long-acting Top1 inhibitor providing sustained levels of active metabolite throughout the entire chemotherapy cycle. The phase 3 BEACON trial compared EP to treatment of physician's choice (TPC) in patients with advanced breast cancer, demonstrating a non-statistically significant 2.1 month difference in survival favoring EP in the intent to treat population. A novel aspect of the BEACON trial is to explore the utility of biomarkers measured in CTCs for predicting efficacy with EP. Pre- and post-treatment CTCs were isolated from blood of 77% of the 852 BEACON patients. Target-specific pharmacodynamic biomarkers for EP measured in CTCs were analyzed to identify patients most responsive to treatment with EP. Methods: Donation of blood samples for CTC analysis was voluntary. Participating BEACON patients had serial (baseline, Cycle 2 Day 1 [C2D1], Cycle 4 Day 1 [C4D1], End of Treatment) 7.5-mL whole blood samples drawn in EDTA tubes and shipped within 96 hours ambient to ApoCell (Houston, TX) for processing. PBMCs were separated by Ficoll® gradient, and CTCs were isolated using ApoStream® technology. Isolated cells were deposited on three slides and stained for DAPI, CD45, cytokeratin markers, as well as Top1, Top2, Ki67, γH2AX, Rad51, ABCG2, and TUNEL. Biomarkers were quantified by iCys® laser scanning cytometer equipped with image analysis software, and correlated with OS using Cox multiple regression and Kaplan-Meier analyses. Results: The CTC substudy yielded 611 pre-treatment, 519 C2D1, 268 C4D1, and 431 End of Treatment samples. Among the successfully processed blood samples, 98% had detectable CTCs, with a median of 63, 46, 51, and 57 CTCs/mL at baseline, C2D1, C4D1, and End of Treatment, respectively. Cox regression analyses of CTC number and percentage of Top1, Top2, Ki67, or TUNEL positive CTCs identified a correlation for post-treatment number of Top1-positive CTCs with OS in patients receiving EP. To assess the impact of Top1-positive CTCs, patients were classified as Top1-High (&amp;gt; median) or Top1-Low (≤ median) based on the percent of Top1-positive CTCs at baseline. Among the Top1-High patients at baseline, significantly improved OS (HR 0.54, p=0.007) was observed for those who converted to Top1-Low after their first treatment with EP (C2D1), but not TPC (HR 1.12, p=0.613). These results suggest that decreased number of Top1-positive CTCs may reflect EP target engagement with Top1, as these patients derived the most benefit from treatment. Conclusions: CTC collection and analysis was successfully incorporated into the phase 3 BEACON study, with 77% patient participation. CTC detection rate using ApoStream® was high, permitting evaluation of biomarkers at baseline and post-treatment. Significantly improved OS was observed in patients who had a decreased number of Top1-positive CTCs following cycle 1 of EP. Citation Format: Rugo HS, Cortes J, Awada A, O'Shaughnessy J, Twelves C, Im S-A, Hannah AL, Lu L, Sy S, Caygill K, Zajchowski D, Davis DW, Hoch U, Perez EA. Early change in topoisomerase 1 (Top1) positive circulating tumor cells (CTCs) is associated with overall survival (OS) in patients with advanced breast cancer after treatment with etirinotecan pegol. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-13-02.