Circulating Tumor Cells Counts Research Articles

OCT4‑positive circulating tumor cells may predict a poor prognosis in patients with metastatic castration‑resistant prostate cancer treated with abiraterone plus prednisone therapy.

Octamer-binding transcription factor 4 (OCT4) and circulating tumor cells (CTCs) are key factors associated with tumor metastasis and drug resistance in cancer. The present prospective study aimed to investigate the prevalence of OCT4-positive (OCT4+) CTCs and the potential association with the clinical features and survival of patients with metastatic castration-resistant prostate cancer (mCRPC) treated with abiraterone + prednisone. In total, 70 patients with mCRPC treated with abiraterone + prednisone were enrolled in the present study and peripheral blood samples were collected prior to treatment initiation to determine CTC count via a Canpatrol system. RNA in situ hybridization was performed for OCT4+ CTC quantification. Lactate dehydrogenase (LDH) was detected by automatic biochemical analyzer (AU54000, OLYMPUS). Results demonstrated that 34 (48.6%), 21 (30.0%) and 15 (21.4%) patients harbored OCT4+ (CTC+/OCT4+) or OCT4-negative CTCs (CTC+/OCT4-) or were CTC-negative (CTC-), respectively. Notably, CTC+/OCT4+ occurrence was associated with visceral metastasis and high levels of LDH. In addition, radiographic progression-free survival [rPFS; median, 15.0, 95% confidence interval (CI), 9.6-20.4 vs. not reached vs. median, 29.5, 95% CI, 18.6-40.4 months; P=0.001] and overall survival (OS) were significantly decreased (median, 27.3, 95% CI, 20.1-34.5 vs. not reached vs. not reached; P=0.016) in CTC+/OCT4+ compared with CTC+/OCT4- and CTC- patients. Subsequently, the adjustment was performed by multivariate Cox regression models, which revealed that CTC+/OCT4+ (vs. CTC+/OCT4- or CTC-) was independently associated with decreased rPFS [hazard ratio (HR), 3.833; P<0.001] and OS (HR, 3.938; P=0.008). In conclusion, OCT4+ CTCs were highly prevalent in patients with mCRPC and associated with visceral metastasis and increased levels of LDH. Thus, the presence of OCT4+ CTCs may serve as an independent prognostic factor for patients with mCRPC treated with abiraterone + prednisone.

Experimental study of HIFU incomplete ablation on the damage effect and prognosis of rabbit VX2 breast cancer model

Purpose High-intensity focused ultrasound (HIFU) represents an emerging noninvasive modality for tumor treatment. While biological responses and immunological change associated with incomplete ablation have not been thoroughly investigated. This study aims to evaluate the damage effect of HIFU incomplete ablation via establishing animal model and further explore its possible mechanism to inhibit tumor growth. Methods The rabbit VX2 breast cancer model was established and received HIFU treatment with complete ablation (100% tumor volume) and incomplete ablation (about 80% tumor volume) under real-time B-ultrasound monitoring. Histopathological alterations, dynamics of tumor cell apoptosis and proliferation, expression levels of VEGF, MMP-9, IL-2R, TGF-β1, HSP-70, IL-6, IL-8, and INF-γ, and the presence of circulating tumor cells (CTCs) were evaluated post-HIFU incomplete ablation. Results For HIFU 80% ablation group, there was an 85.85% reduction in tumor volume 21 days post-intervention. A marked increase in tumor cell apoptosis and a concomitant decrease in proliferation were observed. Notably, distant tumor metastasis rates, CTC counts, and expression levels of VEGF, MMP-9, IL-2R, TGF-β1, IL-6, and IL-8 were significantly reduced. In contrast, INF-γ and HSP-70 expressions were notably elevated, aligning with findings from the 100% ablation group. Conclusions HIFU incomplete ablation, with an 80% tumor ablation rate, induces substantial tumor damage, augments tumor cell apoptosis, and triggers an anti-tumor immune response, curtailing metastasis. These insights may underpin further investigations into the therapeutic implications of HIFU incomplete ablation.

Prognostic Role of Circulating Tumor Cells in Patients with Metastatic Castration-Resistant Prostate Cancer Receiving Cabazitaxel: A Prospective Biomarker Study.

Circulating tumor cells (CTCs) appear to be a promising tool for predicting the clinical outcome and monitoring the response to treatment in patients with solid tumors. The current study assessed the clinical relevance of monitoring CTCs in patients with metastatic castration resistant prostate cancer (mCRPC) treated with cabazitaxel. Patients with histologically confirmed mCRPC who were previously treated with a docetaxel-containing regimen and experienced disease progression were enrolled in this multicenter prospective study. CTC counts were enumerated using the CellSearch system at baseline (before cabazitaxel initiation), after one cabazitaxel cycle (post 1st cycle) and at disease progression (PD). Patients were stratified into predetermined CTC-positive and CTC-negative groups. The phenotypic characterization was performed using double immunofluorescence staining with anti-CKs and anti-Ki67, anti-M30 or anti-vimentin antibodies. The median PFS and OS were 4.0 (range, 1.0-17.9) and 14.5 (range, 1.2-33.9) months, respectively. At baseline, 48 out of 57 (84.2%) patients had ≥1 CTCs/7.5 mL of peripheral blood (PB) and 37 (64.9%) had ≥5 CTCs/7.5 mL of PB. After one treatment cycle, 30 (75%) out of the 40 patients with available measurements had ≥1 detectable CTC/7.5 mL of PB and 24 (60%) ≥ 5CTCs/7.5 mL of PB; 12.5% of the patients with detectable CTCs at the baseline sample had no detectable CTCs after one treatment cycle. The detection of ≥5CTCs/7.5 mL of PB at baseline and post-cycle 1 was associated with shorter PFS and OS (p = 0.002), whereas a positive CTC status post-cycle 1 strongly correlated with poorer OS irrespective of the CTC cut-off used. Multivariate analysis revealed that the detection of non-apoptotic (CK+/M30-) CTCs at baseline is an independent predictor of shorter OS (p = 0.005). In patients with mCRPC treated with cabazitaxel, CTC counts both at baseline and after the first cycle retain their prognostic significance, implying that liquid biopsy monitoring might serve as a valuable tool for predicting treatment efficacy and survival outcomes.

Clinical values of circulating tumor cells count in localized renal cell carcinoma.

Renal cancer is one of the most common malignant tumors of the urinary system, with distant metastasis occurring 30% of patients. Therefore, early detection and monitoring of tumor progression are of great significance in the diagnosis and treatment of renal cancer. However, current biomarkers used to diagnose, monitor recurrence and assess prognosis of renal cancer are still uncertain. Circulating tumor cells (CTCs) are tumor cells detached from the primary tumor or metastasis, invaded and existing in the peripheral blood, and are one of the most promising liquid biopsy targets because they can provide complete cell biological information. Microfluidic chip has advantages of miniaturization, high integration, and fast analysis, which has advantages in CTC separation and enrichment. In this study, 1 mL peripheral blood of each 30 patients with early localized renal cancer was collected before and 1 day after surgery. CTC enrichment was performed by microfluidic chip and CTCs were identified by immunofluorescence staining. All patients were followed up for a median of 17 months. The number of CTCs before surgery was higher than that after surgery (P<0.001), and the number was positively correlated with tumor-node-metastasis (TNM) stage and International Society of Urological Pathology (ISUP) grade. Patients in group CTC ≤2 had a longer progression-free survival (PFS) than those in group CTC ≥3 (P<0.05). Surgical treatment can remarkably reduce the number of CTCs in patients, and CTC counts can also play a role in monitoring tumor load and predicting prognosis in renal cancer.

Phenotypic characteristics of circulating tumor cells and predictive impact for efficacy of chemotherapy in patients with pancreatic cancer: a prospective study.

Early chemoresistance and tumor mass progression are associated with poor prognosis in pancreatic ductal adenocarcinoma (PDAC). Circulating tumor cells (CTCs) have been studied as potential predictors of treatment response and prognosis in PDAC; however, this approach has yet to be applied in clinical practice. The aim of our study was to investigate the phenotypic characteristics of CTCs and determine their predictive value for PDAC progression. We prospectively enrolled 40 patients who were pathologically diagnosed with PDAC and collected blood samples at diagnosis, 2 months after diagnosis, and during disease progression or recurrence. We used a microfabricated filter-based enrichment system to retrieve and analyze CTCs, which were classified using immunofluorescence staining (CD45, EpCAM, and vimentin). Our study included 20 women and 20 men (median age, 66 years). Overall, 45% of the patients (18/40) had disseminated disease, and 77.5% (31/40) received chemotherapy. Multivariate analysis revealed that the total CTC count and carbohydrate antigen 19-9 level at 2 months after diagnosis were associated with disease progression (P<0.05). Linear mixed model analysis revealed that the total CTC count and vimentin-positive CTCs were significantly correlated with treatment response during chemotherapy (P=0.024 and 0.017, respectively). Kaplan-Meier analysis showed that total CTC positivity at 2 months was significantly associated with poor progression-free survival (P=0.038). Our study's findings suggest that CTCs can serve as predictive biomarkers of clinical outcomes in patients with PDAC receiving palliative chemotherapy. In particular, the total CTC count and vimentin-positive CTCs showed changes associated with the chemotherapy response.

MFast-SeqS-based aneuploidy score in circulating cell-free DNA is a prognostic biomarker in prostate cancer.

Multiple prognostic biomarkers, including circulating tumour cell (CTC) counts, exist in metastatic castration-resistant prostate cancer (mCRPC) patients, but none of them have been implemented into daily clinical care. The modified fast aneuploidy screening test-sequencing system (mFast-SeqS), which yields a genome-wide aneuploidy score, is able to reflect the fraction of cell-free tumour DNA (ctDNA) within cell-free DNA (cfDNA) and may be a promising biomarker in mCRPC. In this study, we investigated the prognostic value of dichotomized aneuploidy scores (< 5 vs. ≥ 5) as well as CTC counts (< 5 vs. ≥ 5) in 131 mCRPC patients prior to treatment with cabazitaxel. We validated our findings in an independent cohort of 50 similarly treated mCRPC patients. We observed that, similar to the dichotomized CTC count [HR: 2.92; 95% confidence interval (CI);1.84-4.62], dichotomized aneuploidy scores (HR: 3.24; CI: 2.12-4.94) significantly correlated with overall survival in mCRPC patients. We conclude that a dichotomized aneuploidy score from cfDNA is a prognostic marker for survival in mCRPC patients within our discovery cohort and in an independent mCRPC validation cohort. Therefore, this easy and robust minimally-invasive assay can be readily implemented as a prognostic marker in mCRPC. A dichotomized aneuploidy score might also be used as a stratification factor in clinical studies to account for tumour load.

Relationship of Ki-67 index in biopsies of metastatic breast cancer tissue and circulating tumor cells (CTCs) at the time of biopsy collection

BackgroundThe proliferation marker Ki-67 is a major pathological feature for the description of the state of disease in breast cancer. It helps to define the molecular subtype and to stratify between therapy regimens in early breast cancer and helps to assess the therapy response. Circulating tumor cells (CTCs) are a negative prognostic biomarker for progression free (PFS) and overall survival (OS) in patients with metastatic breast cancer. Therefore, the CTC count is often described as surrogate for the tumor burden. Both, decrease of Ki-67 and CTC count are considered as evidence for therapy response. The presented work analyzed the correlation between the Ki-67 indices of metastatic tissue biopsies and CTC counts in biopsy time-adjacent peripheral blood samples.Patients and methodsBlood samples from 70 metastatic breast cancer patients were obtained before the start of a new line of systemic therapy. CTCs were enumerated using CellSearch® (Menarini Silicon Biosystems, Bologna, Italy) whereas intact CTCs (iCTCs) and non-intact or apoptotic CTCs (aCTCs) were distinguished using morphologic criteria. The proportion of cells expressing Ki-67 was evaluated using immunohistochemistry on biopsies of metastases obtained concurrently with CTC sampling before the start of a new line of systemic therapy.Results65.7% of patients had a Ki-67 index of > 25%. 28.6% of patients had ≥ 5, 47.1% ≥ 1 iCTCs. 37.1% had ≥ 5, 51.4% ≥ 1 aCTCs. No correlation was shown between Ki-67 index and iCTC and aCTC count (r = 0.05 resp. r = 0.05, Spearman’s correlation index). High CTC-counts did not coincide with high Ki-67 index. High Ki-67, ≥ 5 iCTCs and aCTCs are associated with poor progression free (PFS) and overall survival (OS).ConclusionCTCs and Ki-67 are independent prognostic markers in metastatic breast cancer. High Ki-67 in metastatic tumor tissue is not correlated to high iCTC or aCTC counts in peripheral blood.

Prognostic value of neutrophil-to-lymphocyte ratio in patients with metastatic castration-resistant prostate cancer receiving prostate-specific membrane antigen targeted radionuclide therapy.

Neutrophil count:lymphocyte count ratio (NLR) may be a prognostic factor for men with advanced prostate cancer. We hypothesized that it is associated with prostate-specific antigen (PSA) response and survival in men treated with prostate-specific membrane antigen (PSMA)-targeted radionuclide therapy (TRT). Data of 180 men with metastatic castration-resistant prostate cancer (mCRPC) who were treated in sequential prospective radionuclide clinical trials from 2002 to 2021 (utilizing 177Lu-J591, 90Y-J591, 177Lu-PSMA-617, or 225Ac-J591) were retrospectively analyzed. We used a logistic regression to determine the association between NLR and ≥50% PSA decline (PSA50) and a Cox proportional hazards model to investigate the association between NLR and overall survival (OS). A total of 94 subjects (52.2%) received 177Lu-J591, 51 (28.3%) 177Lu-PSMA-617, 28 (15.6%) 225Ac-J591, and 7 (3.9%) 90Y-J591. The median NLR of 3.75 was used as cut-off (low vs. high NLR; n = 90, respectively). On univariate analysis, NLR was not associated with PSA50 (HR 1.08; 95% confidence interval [CI] 0.99-1.17, p = 0.067). However, it was associated with worse OS (hazard ratio [HR] 1.06, 95% CI 1.02-1.09, p = 0.002), also after controlling for circulating tumor cell count and cancer and leukemia group B risk group (HR 1.05; 95% CI 1.003-1.11, p = 0.036). Men with high NLR were at a higher hazard of death from all causes (HR 1.43, 95% CI 1.05-1.94, p = 0.024). NLR provides prognostic information in the setting of patients with mCRPC receiving treatment with PSMA-TRT.

Correlation analysis of circulating tumor cells and Claudin-4 in breast cancer.

Objective: We aimed to explore the relationship between peripheral blood circulating tumor cells (CTCs) and the expression of Claudin-4 in patients with breast cancer, and further explore the potential impact on clinical prognosis and risk assessment. Methods: We classified and enumerated circulating tumor cells in the blood of breast cancer patients by CTC-enriched in situ hybridization and the detection of Claudin-4 expression by immunohistochemistry. We carried out an analysis of the correlation between the two and the comparison of their impact on clinical parameters and prognosis. Results: There were 38 patients with a low expression of Claudin-4 and 27 patients with a high expression of Claudin-4. Compared with Claudin-4 low-expression patients, the number of CTCs was higher in patients with high Claudin-4 expression (11.7 vs. 7.4, p < 0.001). High Claudin-4 expression was associated with a lower count of epithelial CTCs (E-CTCs) (3.4 vs. 5.0, p = 0.033), higher counts of mesenchymal CTCs (M-CTC) (4.4 vs. 1.1, p < 0.001), and epithelial/mesenchymal CTCs (E/M-CTCs) (4.0 vs. 3.5, p = 0.021). The intensity of Claudin-4 was positively correlated with CTC (rs = 0.43, p = 0.001). Multivariate COX regression analysis showed that CTC counts (HR = 1.3, p < 0.001), Claudin-4 (HR = 4.6, p = 0.008), and Lymphatic metastasis (HR = 12.9, p = 0.001) were independent factors for poor prognosis. COX regression of CTC classification showed that epithelial/mesenchymal CTCs (E/M-CTC) (HR = 1.9, p = 0.001) and mesenchymal CTCs (M-CTC) (HR = 1.5, p = 0.001) were independent influencing factors of adverse reactions in breast cancer patients. Conclusion: The number of CTC in breast cancer is positively correlated with the expression of Claudin-4. High CTC counts and a high proportion of M-CTCs correlated with Claudin-4 expression. CTC counts and Claudin-4 expression were independent predictors of poor prognosis in breast cancer patients.

Analysis of Diagnostic Value of CTC and CTDNA in Early Lung Cancer.

This paper is the exploration and analysis of the diagnostic value of circulating tumor cells (CTC) and circulating tumor deoxyribonucleic acid (ctDNA) in early non-small cell lung cancer (NSCLC).A total of 125 NSCLC patients that hospitalized from March 2019 to December 2020 were selected, of which 64 subjects with stage I-II were listed as the early-stage group, and 61 patients with stage III-IV were classified as the intermediate-advanced group; In addition, 47 patients with benign pulmonary nodules hospitalized within same period were selected as a group of benign pulmonary nodules, and 50 healthy subjects were enrolled as a control group. The levels of CTC and ctDNA, serum tumor markers carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), cytokeratin 21-1 (CYFRA21-1) and gastrin-releasing peptide precursor (pro-GRP) were detected. The diagnostic value of CTC and ctDNA in early NSCLC patients was analyzed by ROC curve. The area under the curve of CTC count for early-stage lung cancer was 0. 949 (P=0. 000, 95%CI: 0. 918-0. 980), and ctDNA was 0. 914 (P=0. 000, 95%CI: 0. 866~0. 963). There were significant differences in CTC count and ctDNA among subjects in each group (P<0. 05). CTC count and ctDNA of the early and intermediate-advanced group were remarkably higher than those of the control group and group of benign pulmonary nodules (P<0. 05), and CTC count and ctDNA of patients in the middle-late group were critically higher than those in the early-stage group (P<0. 05). There were significant differences in serum CEA, NSE, CYFRA21-1 and pro-GRP levels among all groups (P<0. 05). The results showed that CTC and ctDNA in NSCLC patients were significantly positively correlated with CEA, NSE, CYFRA21-1 and pro-GRP (P<0. 05). Peripheral blood CTC and ctDNA levels are significantly increased in NSCLC patients. They are positively correlated with serum tumor markers CEA, NSE, CYFRA21-1 and pro-GRP levels, and are related to tumor progression. CTC and ctDNA have high value in the clinical diagnosis of early NSCLC.

Association of Circulating Tumor Cells, Megakaryocytes and a High Immune-Inflammatory Environment in Metastatic Breast Cancer.

Liquid biopsy is becoming an important source of new biomarkers during the treatment of metastatic cancer patients. Using size-based microfluid technology, we isolated circulating tumor cells (CTCs) from metastatic breast cancer patients to evaluate their presence and cluster formation, as well as the presence of megakaryocytes and immune-inflammatory blood cells, and to correlate their presence with clinicopathological data and overall survival (OS). In total, 59 patients (median age 60.4 years) were included in the study: 62.7% luminal A/B-like, 20.3% HER2-positive, and 17% triple-negative. Our results showed that at least one CTC was present in 79.7% and ≥5 CTCs in 35.2% of the patients. CTC clusters were present in patients with ≥5 CTCs only (in 19.2% of them), and megakaryocytes were present in 52% of all patients. The presence of CTC clusters and megakaryocytes was positively associated with the CTC count. Patients with low pan-inflammatory value (PIV), low systemic immune-inflammatory index (SII), and low relative change from baseline (ΔPIV%, ΔSII%) were associated with significantly higher OS than their counterparts. ΔPIV%, the presence of infection in the last month, and a long duration of metastatic disease were identified as independent prognostic factors for OS. The interplay of CTCs, CTC clusters, megakaryocytes, and PIV needs to be further explored.

Nomograms for postsurgical extrahepatic recurrence prediction of hepatocellular carcinoma based on presurgical circulating tumor cell status and clinicopathological factors.

Extrahepatic recurrence (EHR) is one of the major reasons for the poor prognosis of hepatocellular carcinoma (HCC). The present study aimed to develop and assess the performance of predictive models by using a combination of presurgical circulating tumor cell (CTCs) data and clinicopathological features to screen patients at high risk of EHR to achieve precise decision-making. A total of 227 patients with recurrent HCC and preoperative CTC data from January 2014 to August 2019 were enrolled. All patients were randomly assigned to one of two cohorts: development or validation. Two preoperative and postoperative nomogram models for EHR prediction were developed and multi-dimensionally validated. Patients with EHR had generally lower recurrence-free survival (p < 0.001), and overall survival (p < 0.001), and significantly higher CTC counts (epithelial CTCs, epithelial/mesenchymal hybrid CTCs, and mesenchymal CTCs count, all p < 0.05) than those without EHR. Univariate and multivariate analyses revealed that EHR was associated with four risk factors in the development cohort: total CTC count (p = 0.014), tumor size (p = 0.028), node number (p = 0.045), and microvascular invasion (p = 0.035). These factors were incorporated into two nomogram models (preoperative and postoperative), which reliably predicted EHR through multidimensional verification (e.g., calibration plot, receiver operating characteristic analysis, decision curve analysis, and clinical impact curve analysis) in the development and validation cohorts, respectively. With threshold of scores of 100.3 and 176.8 before and after surgery respectively, both nomograms were able to stratify patients into two distinct prognostic subgroups (all p < 0.05). The present study proposed two nomogram models integrating presurgical CTC counts and clinicopathological risks and showed relatively good predictive performance of EHR, which may be beneficial to the clinical practice of HCC recurrence. Further multicenter studies are needed to assess its general applicability.

Longitudinal Assessment of Circulating Tumor Cells and Outcome in Small Cell Lung Cancer: A Sub-Study of RASTEN-A Randomized Trial with Low Molecular Weight Heparin.

Circulating tumor cells (CTCs) may provide a liquid biopsy approach to disease monitoring in small cell lung cancer (SCLC), a particularly aggressive tumor subtype. Yet, the prognostic role of CTCs during and after treatment in relation to baseline remains ill-defined. Here, we assessed the value of longitudinal CTC analysis and the potential of low-molecular-weight heparin (LMWH) to reduce CTC abundance in SCLC patients from a randomized trial (RASTEN). Blood samples were collected at baseline, before chemotherapy Cycle 3, and at 2-month follow-up from 42 patients in total, and CTCs were quantified using the FDA-approved CellSearch system. We found a gradual decline in CTC count during and after treatment, independently of the addition of LMWH to standard therapy. Detectable CTCs at baseline correlated significantly to reduced survival compared to undetectable CTCs (unadjusted hazard ratio (HR) of 2.75 (95% CI 1.05-7.20; p = 0.040)). Furthermore, a persistent CTC count at 2-month follow-up was associated with a HR of 4.22 (95% CI 1.20-14.91; p = 0.025). Our findings indicate that persistently detectable CTCs during and after completion of therapy offer further prognostic information in addition to baseline CTC, suggesting a role for CTC in the individualized management of SCLC.

Baseline circulating tumor cell (CTC) count as a prognostic marker of overall survival (OS) in metastatic hormone sensitive prostate cancer (mHSPC): Results from SWOG S1216, a phase III randomized trial of androgen deprivation plus orteronel (cyp17 inhibitor) or bicalutamide.

5080 Background: Biomarkers are needed to predict clinical outcomes in mHSPC. We previously reported that baseline CTC counts in S1216 were prognostic of PSA response and disease progression ( ASCO 2020; CCR 2021). However, the trial’s primary overall survival (OS) endpoint was not yet mature at that time. Here we present the final results of S1216 using all available samples to assess the prognostic value of CTC counts for response, progression, OS, and treatment arm interactions. Methods: In S1216, peripheral blood was drawn with informed consent at registration (baseline) and at progression to metastatic castrate resistant prostate cancer (mCRPC). CTCs were enumerated on the FDA-cleared CellSearch platform (Menarini). CTC counts were evaluated for associations with 3 pre-specified trial endpoints: 7-month PSA (7mPSA) ≤ 0.2 ng/ml vs. 0.2–4.0 vs. &gt; 4.0 using a generalized logit model; and progression-free survival (PFS) and OS using Cox regression. Results: From 2014 to 2021, 503 evaluable samples were collected at baseline and 93 at progression. Baseline CTC count was ≥5 in 11.9% of samples, 1-4 in 19.3%, and 0 in 66.8%. Comparing men with 0 vs. ≥5 CTCs at baseline, those with 0 CTCs were significantly more likely to attain a complete PSA response and had significantly lower risk of a PFS event and death after adjusting for clinical covariates (disease burden, bone metastases, age, race, alkaline phosphatase, hemoglobin, PSA, treatment arm). These associations were not modified by treatment arm. Progression CTCs &lt;5 vs. ≥5 also were prognostic of OS (logrank p=0.001), consistent with prior findings in mCRPC. Same-patient CTC counts in matched baseline-progression pairs (n=61) were highly correlated (Spearman p&lt;0.001). Conclusions: CTC count at the start of treatment for mHSPC was highly prognostic of PSA response, PFS, and OS; associations that held in both treatment arms. Moreover, baseline CTC count strongly correlated with progression count, suggesting that mild vs. aggressive disease phenotypes may persist from mHSPC to mCRPC. This evidence from a large prospective phase 3 trial suggests that baseline CTC count is a valuable prognostic marker in men initiating therapy for mHSPC, discriminating those likely to experience favorable vs. unfavorable response and OS. [Table: see text]

Effect of circulating tumor cells distribution in treatment naive and treated patients with advance stage breast cancer on disease burden.

e12517 Background: Breast malignancies is a leading cause of cancer-related mortalities and show ascending incidence rate. Despite advancements in our understanding of the disease, its clinical outcome is often dismal. This largely remains owing to the characteristic wide window of relapse, spanning months to decades after primary treatment. Therefore, continuous monitoring of the disease is an offered choice to detect metastatic progression and recurrence. Circulating tumor cells (CTCs) have emerged as a powerful prognostic tool to predict the disease outcome in many epithelial cancers. CTCs are a real-time surrogate biomarker accounting for minimal residual disease (MRD) which is often missed in CT PET scanning. This leads to a progression of metastasis when the patient is often considered as ‘clinically disease free’. Here, we analyzed the presence of CTCs in treatment-naïve and chemo-recipient breast cancer patients. Methods: In this retrospective study on 417 breast cancer patients, CTCs were isolated from 1.5 ml of blood using the Drug Controller General of India (DCGI) approved OncoDiscover CTC test. This platform contains affinity-based magnetic nanoparticles to mediate EpCAM-based CTC isolation. CTCs were detected as CK18+, DAPI+ and CD45- cells based on automated digital imaging platform. Results: 42.6 % (n=178) of patients were clinically at progressive stage (stage II and III) and treatment naïve. On the other hand, 47.4 % of patients received treatment including surgery and chemotherapy. CTCs were not observed in 5.6 % (n=10) of the treatment naïve population while 32% (n=75) of patients who received therapy did not show CTCs. The mean CTC number in treatment naïve patients was 15, while the mean CTC count in patients receiving therapy was drastically reduced to 2. This implied that therapy effectively countered the tumor progression and reduced the shedding of tumor cells in circulation. The distribution of CTC in treatment naïve patients exhibited a bimodal trend centered at values of 10 and 50, suggesting two distinct populations of patients with respect to CTC count. CTC count did not show any correlation with the age in both population groups. Surprisingly CTC count in younger patients (20-50 years) was 50% higher compared to the older population (50-75 years). Conclusions: The presence of CTCs in treatment naïve, progressive breast cancer patients indicated the biologically aggravated disease. Although therapeutic intervention drastically reduced the CTC burden, their presence in a large population was suggestive of an MRD and the likelihood of recurrence after discontinuation of therapy. A distinct pattern of CTC occurrences in Tx naïve and Tx recipient patient suggested that CTCs can be an important clinical indicator to monitor the therapy response, progression and residual disease.

Circulating tumor cells in patients with hormone receptor-positive, HER2-negative metastatic breast cancer receiving palbociclib with fulvestrant after progression on palbociclib with an aromatase inhibitor.

e13018 Background: High levels of circulating tumor cells (CTCs) at initiation of therapy in patients with metastatic breast cancer (MBC) are associated with worse prognosis. In patients with hormone receptor–positive (HR+), HER2-negative MBC, the benefit of maintaining CDK4/6 inhibitor (CDK4/6i) after progression on first-line therapy with endocrine therapy and CDK4/6i is not fully defined. To study the relationship between CTCs, tumor characteristics, and clinical outcomes, we enumerated CTC dynamics in patients with HR+ HER2- MBC enrolled on a phase II, multi-center, open-label interventional trial of palbociclib and fulvestrant after disease progression on prior palbociclib with an aromatase inhibitor (NCT02738866). Methods: Blood samples from study participants were collected at baseline (pretreatment), cycle 2 (C2, 8 weeks after initiation of fulvestrant and palbociclib), and at disease progression. Using a previously analytically validated assay (CellSearch), CTCs were enumerated. Progression-free survival (PFS) was estimated using the Kaplan Meier method. The relationship between CTC count at baseline (&lt; 5, &gt;5/7.5 ml Whole Blood (WB)) and PFS was analyzed using Cox proportional hazards regression. The association between PFS and CTC count among patients with baseline CTC ≥5 was estimated with a Cox proportional hazards model, adjusting for age, race, and progesterone receptor (PgR). Results: Between May 2017 and September 2022, baseline samples were collected from 52 of 60 trial participants enrolled at 5 centers in the United States, mean age 55 years (SD 14). Baseline CTC counts were &lt;5 in 30/52 (58%) and &gt;5 in 22/52 (42%) of participants. Among participants at baseline, only tissue PgR negativity was associated with higher likelihood of having elevated CTCs &gt;5 (p = 0.04). Association of CTCs &gt;5 and select patient and tumor characteristics is shown in Table 1. There was no statistically significant association between continuously measured CTC and PFS among those with elevated CTCs at baseline. Median duration of therapy among the entire 52 participant cohort was 4 months. Median PFS in participants with baseline CTC &lt;5 vs &gt;5/7.5 ml WB was 7.83 (95% CI [5.37, 12.60]) and 2.83 (95% CI [1.77, 4.73]) months, respectively (HR): 2.10, 95% CI [1.15, 3.82], p = 0.01). Conclusions: Baseline CTCs &gt;5/7.5 ml WB conferred a 2-fold increased risk of disease progression. Tissue PgR negativity was associated with baseline CTCs &gt;5. These data can be used to inform new studies in which baseline and early change in CTCs may inform second line treatment decisions in women with HR+, HER2- MBC. [Table: see text]

Phase I dose-escalation results of prostate-specific membrane antigen-targeted radionuclide therapy (PSMA-TRT) with alpha-radiolabeled antibody 225Ac-J591 and beta-radioligand 177Lu-PSMA I&amp;T.

5018 Background: PSMA may be targeted by antibodies (mAb) or small molecules (SML), with different kinetics and biodistribution. mAb with longer circulation time and marrow exposure, but decreased access to luminal PSMA expression (e.g. salivary glands, intestine, kidney). SML diffuse to all sites of PSMA expression and then excreted. Alpha radionuclides emit more energy over shorter range vs beta. Pre-clinical data combining mAb and SML supports synergy, with enhanced uptake and retention of SML. Here, we present phase I dose-escalation results of a phase I/II trial investigating combo 225Ac-J591 with 177Lu-PSMA-I&amp;T (aka PNT2002). Methods: Eligibility criteria include progressive mCRPC, ≥1 prior AR pathway inhibitor (ARPI), prior chemo (or unfit/refuse), ≥1 lesion with SUVmax &gt;liver. Doses: 177Lu-PSMA-I&amp;T (6.8 GBq); 225Ac-J591 (30, 35, or 40 KBq/kg), up to 2 doses of combo TRT 8 weeks (wks) apart with 177Lu SPECT following each dose. Primary objectives: dose-limiting toxicity (DLT) and recommended phase II dose; phase II will test the proportion of patients (pts) obtaining &gt;50% PSA decline (PSA50). DLT defined as G4 myelosuppression lasting &gt;1 wk, Gr&gt;2 non-hematologic adverse event (AE), any Gr attributed AE delaying therapy &gt;3 wks. Additional endpoints include progression-free and overall survival, radiographic response rate, safety, circulating tumor cell (CTC) changes, pt reported outcomes, PSMA imaging, blood/tissue correlatives. Results: 18 pts treated (6 at each dose level); 3 did not receive the 2nd dose due to progressive disease or withdrawal. Median age 70 (range 54-86), PSA 54.4 (2.43-9614). 13 (72%) with bone, 9 (50%) lymph node, 2 (11%) liver, 2 (11%) lung mets. 10 (56%) pts CALGB risk category high, 7 (39%) intermediate, 1 low. Previous therapies: 11 (61%) with &gt;1 ARPI, 12 (67%) chemo, 5 (28%) sip-T, 3 (17%) radium-223. 2 of 6 pts with DLT at 40 KBq/Kg (Gr 2 or 3 thrombocytopenia delaying cycle 2 by &gt;3 wk); no DLT observed in other cohorts. As submission, 7 pts (39%) remain on study, including 1 without progression at 16 months and another with undetectable PSA at 10 months. With follow up ongoing, 17 (94%) with PSA decline, 9 (50%) with PSA50. Of those with paired CTC counts, 4 of 5 (80%) converted from unfavorable to favorable CTC count, 4 of 8 (50%) from detectable to undetectable, 1 of 2 (50%) remained undetectable. AEs include 3 (17%) neutropenia (all Gr &lt;2), 12 (67%) thrombocytopenia (3 Gr 3), 10 (56%) anemia (3 Gr 3), 10 (56%) pain flare (1 Gr3 in pt with cord compression), 12 (67%) xerostomia (one Gr2), 11 (61%) nausea (all Gr 1), 9 (50%) fatigue (all Gr 1). Conclusions: The combination of dual-PSMA targeting with mAb + SML and alpha + beta is feasible with follow up ongoing. Efficacy will formally be tested in the upcoming phase II portion of the study with 225Ac-J591 at 35 KBq/Kg and 177Lu-PSMA I&amp;T at 6.8 GBq. Clinical trial information: NCT04886986 .

Prognostic value of tumor-derived extracellular vesicles and circulating tumor cells in metastatic breast cancer (BC): A focus on inflammatory BC.

1098 Background: Circulating tumor cells (CTCs) are an independent prognostic factor in metastatic breast cancer (MBC). The prognostic value of CTCs and the optimal cutoff for patients (pts) with inflammatory breast cancer (IBC), one of the most aggressive types of BC, has not been fully established. Recent evidence showed the complementary prognostic value of tumor-derived extracellular vesicles (tdEVs) to CTCs in MBC. The significance of tdEVs in IBC is unexplored. This study aimed to assess the prognostic value of CTCs and tdEVs in metastatic IBC. Methods: This study retrospectively analyzed 308 pts with MBC enrolled at Northwestern University (Chicago, IL) before starting a new line of therapy between 2016 and 2021 (NU16B06 trial). Blood samples were processed for CTCs using the CellSearch system. We applied the open source ACCEPT software to archived CellSearch images to enumerate CTCs and tdEVs. TdEVs cutoff levels were &lt;20 (low), 20-79 (intermediate), and ≥80 (high), as previously reported. The association of CTCs and tdEVs with overall survival (OS) was tested in the overall population (OvP) and IBC pts. Results: Of the 308 pts, 69 were diagnosed with IBC. 51% of pts received first-line therapy. CTCs enumerated by ACCEPT were strongly correlated with manual count (r=0.86) and hence used for this analysis. Median CTC count was 1 [interquartile range (IQR) 0-7] in IBC pts and 3 (IQR 0-14) in non-IBC (p=0.11). A significantly lower median tdEVs count was observed in IBC (7; IQR 3-45) than in non-IBC (22; IQR 4-137) pts (p=0.03). In IBC, higher CTC and tdEV counts were seen in the triple negative subtype (p=0.03) and non-visceral involvement (p=0.02), respectively. In the OvP median OS (mOS) was worse among pts with ≥5 CTCs (HR 2.6; p=0.001) and with elevated tdEVs (HR 3.3; p&lt;0.001). Only tdEVs were independently associated with poorer OS in multivariable analysis. In pts with &lt;5 CTCs there was a stepwise decrement in OS with increased tdEVs count (p=0.3); in pts with ≥5 CTCs, elevated tdEVs levels were associated with significantly worse OS (p=0.03). IBC pts with ≥5 CTCs had shorter mOS (8 vs 47 months; HR 3.6; p&lt;0.001); this association was weaker using ≥1 as CTC cutoff (HR 2.4; p=0.01). OS was adversely associated with increasing tdEVs levels (33 vs 23 vs 7 months for low, intermediate, and high subgroups, respectively; HR 3.7; p=0.001). Furthermore, elevated tdEVs were associated with shorter mOS in pts with ≥1 (p=0.055) and ≥5 CTCs (p=0.6). Among pts with &lt;5 CTCs no significant difference emerged among tdEVs subgroups (p=0.6). Conclusions: This study confirmed the strong prognostic significance of CTCs and tdEVs in MBC, including IBC. Pts with IBC had fewer CTCs and tdEVs compared to non-IBC, probably due to the predominant lymphatic spread of IBC. tdEVs offer the possibility to better define prognosis of IBC pts. Further studies are needed to evaluate their complementarity to CTCs.

Monitoring epithelial, epithelial-mesenchymal, and mesenchymal circulating tumor cells on papillary thyroid cancer following thyroidectomy: A prospective cohort study.

6097 Background: Monitoring the effectiveness of cancer-removal surgery is challenging in most cases. Therefore, robust and non-invasive techniques have been developed, and liquid biopsy is an apparent method for that purpose. In this prospective cohort study, we examined whether one type of liquid biopsy, an enumeration of circulating tumor cells (CTCs), can monitor the effectiveness of thyroidectomy in patients with papillary thyroid cancer (PTC). Methods: From January 2021 to January 2022, we recruited 62 PTC patients who had operated on isthmectomy, lobectomy, and total thyroidectomy for this study at Seoul National University Bundang Hospital. The blood samples from the recruited patients were collected before surgery and two weeks and three months after the surgery for CTC detection. We collected peripheral blood samples by venipuncture from each patient in EDTA tubes and stored them at 4°C until isolation and characterization of CTCs (within 6 hours). Results: We found the CTCs in 87% (54/62) of PTC patients, with an average number of 8.0. This number significantly decreased after thyroidectomy, with an average of 5.3 and 4.3 post-operation of two weeks and three months, respectively. In the peripheral blood of PTC patients, the CTCs with epithelial-mesenchymal and mesenchymal phenotypes were significantly more frequent than the epithelial phenotype of CTCs. Furthermore, PTC patients with lymphatic invasion, lymph node metastasis, or BRAF V600E mutation showed significantly decreased CTC count after surgery. Conclusions: PTC patients had a significantly higher number of CTCs undergoing epithelial-mesenchymal transition and showed a significant decrease in CTC count after surgery. This indicates that liquid biopsy using CTC enumeration can satisfy the purpose of monitoring the effectiveness of cancer-removal surgery. Clinical trial information: KCT0008179.

Circulating tumor cells (CTCs) detection and isolation in different subtypes of early-stage breast cancer patients from Bangladesh.

e12529 Background: Breast cancer is a highly heterogeneous pathophysiology characterized by poor outcomes. Due to the increasing incidence and disease progression rates and undefined relapse periods, reliable disease monitoring is a challenge and has remained an unmet need. Advancements in liquid biopsy have significantly enhanced our understanding of clinical oncology. CTC-based liquid biopsy is emerging as a reliable prognostic tool to predict various clinical indicators. Although extensively investigated in metastatic breast cancers, little is known about CTCs in early-stage breast cancers. CTCs with respect to different molecular subtypes of breast cancer in early-stage breast cancer patients is evaluated. Methods: In this prospective clinical trial (CMC 59.27.0000.013.19 PG.009.2022/262) 40 early-stage patients with luminal (A +B, 33.33%), HER 2 positive (12.8%), triple-negative (12.8%) and undetermined (41.07%) subtype were recruited. CTCs were isolated in 1.5 ml blood using the Drug Controller General of India approved OncoDiscover CTC test. This platform contains affinity-based magnetic nanoparticles to mediate EpCAM-based CTC isolation. CTCs were detected as CK18+, DAPI+, and CD45- cells using a fluorescence detection-based automated digital imaging platform. Results: CTCs were detected in 60 % of patients with a mean CTC count of 1 cell / 1.5ml blood. Among total positive patients, the luminal subtype was the least positive (46 %), followed by TNBC (60 %) and undetermined (62.5 %) subgroup, while all HER2-positive patients showed the presence of CTCs. Besides individual cells, CTC clusters were detected in 12.5 % of patients and they were equally distributed in luminal and HER2-positive subpopulations. When analyzed on the scale of tumor grade, grade I patients did not show the presence of CTC, while 58.33 % of grade II patients had ≥ 1 CTC. All grade III patients showed the presence of ≥ 1 CTC. CTC count was high among CTC-positive grade II patients (average 2 CTCs) and correlated well with the presence of CTC clusters in these patients. Patients who had surgical intervention had a low CTC burden compared to patients who did not have a surgical resection. 75 % of treatment naïve patients showed the presence of CTC while 58 % of patients receiving chemotherapy alone showed the presence of 1 CTC. 50 % of patients who had surgery followed by CT+RT showed the presence of 1 CTC. Conclusions: The presence of CTCs may suggest for biological progression of disease in early-stage BC patients. CTC detected in all HER2-positive patients suggested the high shedding nature of these tumors, which correlates well with their reported migratory tendency. The presence of CTCs did not show a clear correlation with the treatment regimen. However, this data is based on a single time point and needs longitudinal correlation with CTC on a larger sample size. Clinical trial information: 59.27.0000.013.19 PG.009.2022/262 .