Pathological Complete Responders Research Articles

An online rectal cancer tumoroid biorepository: A resource to facilitate multimodal data integration.

159 Background: Advancing genetic and computational technologies have increased the complexity and quantity of data available in the field of rectal cancer research. As such, there is a need for a centralized source of data to aid and organize current research efforts. To this end, our team has created a unique online biorepository of rectal cancer tumoroids which may serve as a resource for a community of researchers. Methods: The rectal cancer tumoroid biorepository was created in cBioPortal in 2015. Organoids were derived from patient tumor samples (tumoroids). These samples represented multiple treatment timepoints and included primary, recurrent, and metastatic tumors. These tumoroids were further analyzed by various assays such as MSK-IMPACT and IC50 (to fluorouracil, FOLFOX, and FOLFIRI) to obtain patient-specific genomic and chemosensitivity data. A tumoroid profile was then created in cBioPortal for each sample. Clinical information was collected by chart review and annotated into the tumoroid profiles using the unique features of cBioPortal. These included interactive filters and graphical depictions of patient demographics, clinical and pathologic staging, treatment course, clinical response, overall survival, and disease-free survival. Results were organized in an intuitive visual display for convenient analysis. Novel features such as chemosensitivity plots and an interactive patient timeline were incorporated as well. Results: In total, 401 rectal cancer tumoroids have been derived from 177 unique patients. Approximately 32% of the tumoroids were from patients 50 years or younger, and 63% of patients have a treatment naïve sample in our repository. Ten percent of tumoroids were derived from T1-T2 tumors, 56% from T3 tumors, and 17% from T4 tumors. Additionally, 14% of tumoroids were derived from primary tumor recurrences while 6% were derived from metastases. Of the 78% of tumoroids with completely annotated clinical data, 8% were MSI-H, 11% were clinical complete responders, and 5.5% were pathologic complete responders. Lastly, complete IC50 data with clinical correlates has been established for 20% of tumoroids. These data show that tumoroids with a high sensitivity to chemotherapy (FOLFOX) correlated with a 3.3-fold increase in clinical complete response rates in the corresponding patients (p=0.0263). Conclusions: Integrating histopathological, clinicogenomic, and tumoroid response data, this expanding online resource provides a platform to identify valid biomarkers for patient treatment response. This publicly available biorepository built within cBioPortal is intuitive and flexible to accommodate and organize a wide range of data and has the potential to serve as an important resource in rectal cancer research.

291. TREATMENT OUTCOMES ACCORDING TO PATHOLOGICAL RESPONSE AFTER NEOADJUVANT CHEMORADIATION AND SURGEY IN OESOPHAGEAL CANCER

Abstract Background Neoadjuvant chemoradiation followed by surgery is now standard of care for resectable oesophageal cancer. The aim of this study was to analyse various parameters of treatment outcome with respect to pathologic complete responders (pCR) and pathological partial responders. Methods Consecutive 136 patients with operable oesophageal cancer, who received neoadjuvant chemoradiation followed by oesophageal surgery between march 2013 to january 2023 were included. Data was extracted from electronically and physically maintained patient clinical records. Data was collected in mircosoft excel and analysed using Epi Info Version 7.2. Chi square test and student t test were used to test the difference between proportions and means respectively. All tests were 2 tailed and significance level was 0.05. Various demographic, clinical and treatment outcome parameters were analysed according to pathological complete responders (pCR) and pathological partial responders. Results Out of 136 patients, 112(82.3%) had squamous histology. Among 136 patients, 75(55%)had pCR. Postoperative complications were seen in 30(49.18%) of pCR group as compared to 24(32%) in partial responders (p = 0.04). Pulmonary 16(53%) vs 8(33%), cardiac 5(16%) vs 3(12%) and vocal cord palsy 6(20%) vs 8(32%) complications were seen in pCR vs partial responders respectively. 9(14.75%) of pCR group had recurrences as compared to 32(45.33%) in partial responders (p = 0.003). pCR group had distant recurrences in neck 4(66.6%) (p = 0.01) and liver 4(66%) as compared to 2(14.3%) and 4(28.5%) respectively in partial responders. Conclusion High pCR is seen due to more number of patients with squamous histology. pCR has more postoperative pulmonary and cardiac complications which may indicate inherent radiosensitivity and tissue fragility which mandates strict ERAS program and affirms deferred surgery and wait and watch policy for complete clinical responders. Recurrences in pCR are less but are seen mostly in distant sites indicating aggressive surveillance protocol.

Longitudinal immune monitoring of patients with resectable esophageal adenocarcinoma treated with Neoadjuvant PD-L1 checkpoint inhibition

ABSTRACT The analysis of peripheral blood mononuclear cells (PBMCs) by flow cytometry holds promise as a platform for immune checkpoint inhibition (ICI) biomarker identification. Our aim was to characterize the systemic immune compartment in resectable esophageal adenocarcinoma patients treated with neoadjuvant ICI therapy. In total, 24 patients treated with neoadjuvant chemoradiotherapy (nCRT) and anti-PD-L1 (atezolizumab) from the PERFECT study (NCT03087864) were included and 26 patients from a previously published nCRT cohort. Blood samples were collected at baseline, on-treatment, before and after surgery. Response groups for comparison were defined as pathological complete responders (pCR) or patients with pathological residual disease (non-pCR). Based on multicolor flow cytometry of PBMCs, an immunosuppressive phenotype was observed in the non-pCR group of the PERFECT cohort, characterized by a higher percentage of regulatory T cells (Tregs), intermediate monocytes, and a lower percentage of type-2 conventional dendritic cells. A further increase in activated Tregs was observed in non-pCR patients on-treatment. These findings were not associated with a poor response in the nCRT cohort. At baseline, immunosuppressive cytokines were elevated in the non-pCR group of the PERFECT study. The suppressive subsets correlated at baseline with a Wnt/β-Catenin gene expression signature and on-treatment with epithelial–mesenchymal transition and angiogenesis signatures from tumor biopsies. After surgery monocyte activation (CD40), low CD8+Ki67+ T cell rates, and the enrichment of CD206+ monocytes were related to early recurrence. These findings highlight systemic barriers to effective ICI and the need for optimized treatment regimens.

18F-FDG-PET/CT to Detect Pathological Complete Response After Neoadjuvant Treatment in Patients with Cancer of the Esophagus or Gastroesophageal Junction: Accuracy and Long-Term Implications

Purpose The curative strategy for patients with esophageal cancer without distant metastases consists of esophagectomy with preceding chemo(radio)therapy (CRT). In 10–40% of patients treated with CRT, no viable tumor is detectable in the resection specimen (pathological complete response (pCR)). This study aims to define the clinical outcomes of patients with a pCR and to assess the accuracy of post-CRT FDG-PET/CT in the detection of a pCR.MethodsFour hundred sixty-three patients with cancer of the esophagus or gastroesophageal junction who underwent esophageal resection after CRT between 1994 and 2013 were included. Patients were categorized as pathological complete responders or noncomplete responders. Standardized uptake value (SUV) ratios of 135 post-CRT FDG-PET/CTs were calculated and compared with the pathological findings in the corresponding resection specimens.ResultsOf the 463 included patients, 85 (18.4%) patients had a pCR. During follow-up, 25 (29.4%) of these 85 patients developed recurrent disease. Both 5-year disease-free survival (5y-DFS) and 5-year overall survival (5y-OS) were significantly higher in complete responders compared to noncomplete responders (5y-DFS 69.6% vs. 44.2%; P = 0.001 and 5y-OS 66.5% vs. 43.7%; P = 0.001). Not pCR, but only pN0 was identified as an independent predictor of (disease-free) survival.ConclusionPatients with a pCR have a higher probability of survival compared to noncomplete responders. One third of patients with a pCR do develop recurrent disease, and pCR can therefore not be equated with cure. FDG-PET/CT was inaccurate to predict pCR and therefore cannot be used as a sole diagnostic tool to predict pCR after CRT for esophageal cancer.

Refining the Characterization and Outcome of Pathological Complete Responders after Neoadjuvant Chemotherapy for Muscle-Invasive Bladder Cancer: Lessons from the Randomized Phase III VESPER (GETUG-AFU V05) Trial.

Neoadjuvant cisplatin-based chemotherapy (NAC) followed by radical cystectomy and pelvic lymph node dissection is the optimal treatment for patients with muscle-invasive bladder cancer. In recent years, the VESPER trial showed a statistically significant higher progression-free survival with dd-MVAC (dose dense methotrexate, vinblastine, doxorubicin, and cisplatin) compared to GC (gemcitabine and cisplatin). In the present report, we refine the characterization and outcome of patients whose cystectomy specimens were pathologically free of cancer (pathological complete response, pCR). We confirm that these patients portend a better outcome as compared to patients with invasive disease (≥pT1N0) at cystectomy. Nested variant and lymphovascular invasion were identified as adverse predictive factors of pCR. Progression-free survival probability three years after pCR on cystectomy was about 85%, regardless of the NAC regimen. A lower creatinine clearance and the delivery of less than four cycles were associated with a higher risk of relapse. Predicting the efficacy of NAC remains a major challenge. The planned analysis of molecular subtypes in the VESPER trial could help predict which patients may achieve complete response and better outcome.

Accuracy of FDG-PET/CT for Response Evaluation of Muscle-Invasive Bladder Cancer following Neoadjuvant or Induction Chemotherapy

Introduction: The aim of the study was to confirm the diagnostic accuracy of a second FDG-PET/CT following neoadjuvant or induction chemotherapy (NAIC) prior to radical cystectomy for patients with localized muscle-invasive bladder cancer (MIBC). Methods: Retrospective review of 62 consecutive patients with MIBC, that had a first FDG-PET/CT between April 2016 and September 2021. Patients then underwent NAIC, followed by a second FDG-PET/CT and radical cystectomy. Patients with no hypermetabolism in the bladder and lymph nodes on the second FDG-PET/CT were considered metabolic complete responders, while patients with no evidence of residual disease on histopathology were considered pathologic complete responders. The accuracy of the second FDG-PET/CT to distinguish complete responders from patients with residual disease was calculated, with histopathology as gold standard. Results: Of 62 patients, 1 was lost to follow-up, 5 died before radical cystectomy, 5 had delay >2 months between the second FDG-PET/CT and radical cystectomy, and 6 did not undergo radical cystectomy and instead underwent alternative treatment. The study cohort comprised 45 patients, 39 males and 6 females, with an age of 66 ± 6 years. In comparison to histopathology, FDG-PET/CT provided (i) sensitivity of 95% and specificity of 42%, for the overall disease; (ii) sensitivity of 100% and specificity of 36%, for the primary tumor only; and (iii) sensitivity of 97% and specificity of 30%, for the lymph nodes only. Conclusion: FDG-PET/CT has over 95% sensitivity for distinguishing complete responders from patients with residual disease. Thus, FDG-PET/CT can be used for early response evaluation following NAIC to identify patients that did not completely respond to chemotherapy and may require alternative treatment pathways.

Long-term Outcomes of Local and Metastatic Small Cell Carcinoma of the Urinary Bladder and Genomic Analysis of Patients Treated With Neoadjuvant Chemotherapy.

Small cell carcinoma of the bladder (SCCB) is a rare variant of bladder cancer with poor outcomes. We evaluated long-term outcomes of nonmetastatic (M0) and metastatic (M1) SCCB and correlated pathologic response with genomic alterations of patients treated with neoadjuvant chemotherapy (NAC). Clinical history and pathology samples from SCCB patients diagnosed at our institution were reviewed. One hundred and ninety-nine SCCB patients were identified. (M0: 147 [74%]; M1: 52 [26%]). Among M0 patients, 108 underwent radical cystectomy (RC) (NAC: 71; RC only: 23; adjuvant chemotherapy: 14); 14 received chemoradiotherapy; the rest received chemotherapy alone or no cancer-directed therapy. RC-only patients had a median follow-up of 9.1 years, and median disease-free survival (DFS) and overall survival (OS) were 1.1 and 1.2 years, respectively. NAC patients had pathologic response (<pT2pN0) and pathologic complete response (pT0pN0) rates of 48% and 38%, respectively, with median follow-up of 7.2 years, and median DFS and OS of 5.6 and 14.5 years, respectively. NAC responders (<ypT2N0) had superior median DFS (14.5 vs. 0.6 years, hazard ratio [HR] 0.24, P< .001) and OS (14.5 vs. 2.5 years, HR 0.31, P = .002). DFS rates for responders and nonresponders were 76% and 27% at 5 years, and 71% and 23% at 10 years, respectively. Local and central nervous system recurrences were infrequent. Median progression-free survival (PFS) and OS for M1 disease were 6.9 and 10.3 months, respectively. Genomic profiling was performed on 47 NAC patients. Loss of ERCC2 function was significantly enriched among those with pathologic complete response to NAC (mutations present in 50% of pathologic complete responders vs. 15% nonresponders, P = .045). M0 SCCB is chemo-sensitive and patients have excellent long-term survival following response to NAC. Patients with M1 disease have poor survival despite systemic therapy. Loss-of-function mutations of ERCC2 were associated with pathologic complete response to NAC.

OA02.03 Tumor Bulk-RNA Seq Identifies Patients at High Risk of Progression in Non-complete Pathological Responders from NADIM Trial

Pathological response is postulated as a surrogate for survival in patients treated with neoadjuvant chemo-immunotherapy. In this sense, non-complete pathological response (non-CPR) patients present higher risk of disease progression compared to complete pathological responders (CPR). To identify gene expression patterns that may affect long-term outcomes in this high-risk group, we analysed surgical samples of non-CPR patients and characterized the differences between progressors and non-progressors.

Complete Response Evaluation of Locally Advanced Rectal Cancer to Neoadjuvant Chemoradiotherapy Using Textural Features Obtained from T2 Weighted Imaging and ADC Maps.

The prediction of pathological responses for locally advanced rectal cancer using magnetic resonance imaging (MRI) after neoadjuvant chemoradiotherapy (CRT) is a challenging task for radiologists, as residual tumor cells can be mistaken for fibrosis. Texture analysis of MR images has been proposed to understand the underlying pathology. This study aimed to assess the responses of lesions to CRT in patients with locally advanced rectal cancer using the first-order textural features of MRI T2-weighted imaging (T2-WI) and apparent diffusion coefficient (ADC) maps. Forty-four patients with locally advanced rectal cancer (median age: 57 years) who underwent MRI before and after CRT were enrolled in this retrospective study. The first-order textural parameters of tumors on T2-WI and ADC maps were extracted. The textural features of lesions in pathologic complete responders were compared to partial responders using Student's t- or Mann-Whitney U tests. A comparison of textural features before and after CRT for each group was performed using the Wilcoxon rank sum test. Receiver operating characteristic curves were calculated to detect the diagnostic performance of the ADC. Of the 44 patients evaluated, 22 (50%) were placed in a partial response group and 50% were placed in a complete response group. The ADC changes of the complete responders were statistically more significant than those of the partial responders (P = 0.002). Pathologic total response was predicted with an ADC cut-off of 1310 x 10-6 mm2/s, with a sensitivity of 72%, a specificity of 77%, and an accuracy of 78.1% after neoadjuvant CRT. The skewness of the T2-WI before and after neoadjuvant CRT showed a significant difference in the complete response group compared to the partial response group (P = 0.001 for complete responders vs. P = 0.482 for partial responders). Also, relative T2-WI signal intensity in the complete response group was statistically lower than that of the partial response group after neoadjuvant CRT (P = 0.006). As a result of the conversion of tumor cells to fibrosis, the skewness of the T2-WI before and after neoadjuvant CRT was statistically different in the complete response group compared to the partial response group, and the complete response group showed statistically lower relative T2-WI signal intensity than the partial response group after neoadjuvant CRT. Additionally, the ADC cut-off value of 1310 × 10-6 mm2/s could be used as a marker for a complete response along with absolute ADC value changes within this dataset.

Clinical analysis of pathologic complete responders in advanced-stage ovarian cancer

ObjectiveTo determine the clinical characteristics of patients who attained pathologic complete response (pCR) after neoadjuvant chemotherapy (NACT) and to identify specific predictive or prognostic factors associated with pCR. MethodsTwo distinct populations of patients who underwent NACT followed by interval tumor reductive surgery (TRS) were used in this retrospective study. The first contained 472 patients from a single institution. The second contained only pCR patients (67); those identified from population one, plus 44 obtained through collaborative institutions. Cox analysis and log-rank tests were performed to assess associations between clinical characteristics and pCR outcome, recurrence-free survival (RFS), and overall survival (OS). ResultsThe median RFS and OS in our pCR-only population was 24.2 and 80.8 months, respectively, with a median follow-up time of 32.4 months. In our single institution population, 23 patients attained pCR (4.9%) and had longer RFS compared to non-pCR patients with viable microscopic, optimal, or suboptimal residual disease (24.3 vs. 12.1 vs. 11.6 vs. 9.6 months, p = 0.025, 0.012, 0.008, respectively), and longer OS compared to those with optimal or suboptimal residual disease (54.5 vs. 29.4 vs. 25.7 months, p = 0.027, 0.007, respectively). Patients were more than three-fold likely to attain pCR if their CA125 value was normal at the time of surgery (OR 3.54, 95% CI: 1.14–11.05, p = 0.029). ConclusionsWomen with pCR after NACT have significantly longer RFS compared to those with residual viable tumor at the time of interval tumor-reductive surgery, and CA125 is plausible biomarker for identifying these extreme responders preoperatively.

Rectal Cancer Treatment Management: Deep-Learning Neural Network Based on Photoacoustic Microscopy Image Outperforms Histogram-Feature-Based Classification.

We have developed a novel photoacoustic microscopy/ultrasound (PAM/US) endoscope to image post-treatment rectal cancer for surgical management of residual tumor after radiation and chemotherapy. Paired with a deep-learning convolutional neural network (CNN), the PAM images accurately differentiated pathological complete responders (pCR) from incomplete responders. However, the role of CNNs compared with traditional histogram-feature based classifiers needs further exploration. In this work, we compare the performance of the CNN models to generalized linear models (GLM) across 24 ex vivo specimens and 10 in vivo patient examinations. First order statistical features were extracted from histograms of PAM and US images to train, validate and test GLM models, while PAM and US images were directly used to train, validate, and test CNN models. The PAM-CNN model performed superiorly with an AUC of 0.96 (95% CI: 0.95-0.98) compared to the best PAM-GLM model using kurtosis with an AUC of 0.82 (95% CI: 0.82-0.83). We also found that both CNN and GLMs derived from photoacoustic data outperformed those utilizing ultrasound alone. We conclude that deep-learning neural networks paired with photoacoustic images is the optimal analysis framework for determining presence of residual cancer in the treated human rectum.

Analysis of long-term oncological results of clinical versus pathological responses after neoadjuvant treatment in locally advanced rectal cancer

BackgroundNonoperative management after neoadjuvant treatment in low rectal cancer enables organ preservation and avoids surgical morbidity. Our aim is to compare oncological outcomes in patients with clinical complete response in watch and wait strategy with those who received neoadjuvant therapy followed by surgery with a pathological complete response.MethodsPatients with non-metastatic rectal cancer after neoadjuvant treatment with clinical complete response in watch and wait approach (group 1, n = 26) and complete pathological responders (ypT0N0) after chemoradiotherapy and surgery (group 2, n = 22), between January 2011 and October 2018, were included retrospectively, and all of them evaluated and followed in a multidisciplinary team. A comparative analysis of local and distant recurrence rates and disease-free and overall survival between both groups was carried out. Statistical analysis was performed using log-rank test, Cox proportional hazards regression model, and Kaplan-Meier curves.ResultsNo differences were found between patient’s demographic characteristics in both groups. Group 1: distance from the anal verge mean 5 cm (r = 1–12), 10 (38%) stage III, and 7 (27%) circumferential resection margin involved. The median follow-up of 47 months (r = 6, a 108). Group 2: distance from the anal verge mean 7 cm (r = 2–12), 16 (72%) stage III, and 13 (59%) circumferential resection margin involved. The median follow-up 49.5 months (r = 3, a 112). Local recurrence: 2 patients in group 1 (8.3%) and 1 in group 2 (4.8%) (p = 0.6235). Distant recurrence: 1 patient in group 1 (3.8%) and 3 in group 2 (19.2%) (p = 0.2237). Disease-free survival: 87.9% in group 1, 80% in group 2 (p = 0.7546). Overall survival: 86% in group 1 and 85% in group 2 (p = 0.5367).ConclusionOncological results in operated patients with pathological complete response were similar to those in patients under a watch and wait strategy mediating a systematic and personalized evaluation. Surgery can safely be deferred in clinical complete responders.

Potential of miR-21 to Predict Incomplete Response to Chemoradiotherapy in Rectal Adenocarcinoma.

Background: Patients with locally advanced rectal adenocarcinoma (LARC) are treated with neoadjuvant chemoradiotherapy (CRT). However, biomarkers for patient selection are lacking, and the association between miRNA expression and treatment response and oncological outcomes is unclear.Objectives: To investigate miRNAs as predictors of response to neoadjuvant CRT and its association with oncological outcomes.Methods: This retrospective study analyzed miRNA expression (miR-16, miR-21, miR-135b, miR-145, and miR-335) in pre- and post-chemoradiation rectal adenocarcinoma tissue and non-neoplastic mucosa in 91 patients treated with neoadjuvant CRT (50.4 Gy) and proctectomy. Two groups were defined: a pathological complete responders group (tumor regression grade—TRG 0) and a pathological incomplete responders group (TRG 1, 2, and 3).Results: miR-21 and miR-135b were upregulated in tumor tissue of incomplete responders comparing with non-neoplastic tissue (p = 0.008 and p < 0.0001, respectively). Multivariate analysis showed significant association between miR-21 in pre-CRT tumor tissue and response, with a 3.67 odds ratio (OR) of incomplete response in patients with higher miR-21 levels (p = 0.04). Although with no significance, patients treated with 5-fluorouracil (5-FU) presented reduced odds of incomplete response compared with those treated with capecitabine (OR = 0.19; 95% confidence interval (CI) 0.03–1.12, p = 0.05). Moreover, significant differences were seen in overall survival (OS) in relation to clinical TNM stage (p = 0.0004), cT (p = 0.0001), presence of distant disease (p = 0.002), mesorectal tumor deposits (p = 0.003), and tumor regression grade (p = 0.04).Conclusion: miR-21 may predict response to CRT in rectal cancer (RC).

Preoperative Chemoradiation In Rectal Cancer: Predicting Complete Pathological Responders Through Metabolic Imaging

Preoperative Chemoradiation In Rectal Cancer: Predicting Complete Pathological Responders Through Metabolic Imaging

ASO Author Reflections: Does Overall Survival Benefit From Complete Pathologic Responders Vary With Treatment Approach?

ASO Author Reflections: Does Overall Survival Benefit From Complete Pathologic Responders Vary With Treatment Approach?

Health-related quality of life in stage III melanoma patients treated with neoadjuvant ipilimumab and nivolumab followed by index lymph node excision only, compared to therapeutic lymph node dissection: First results of the PRADO trial.

10064 Background: Neoadjuvant ipilimumab and nivolumab induces high pathologic response rates of 74-78% (OpACIN and OpACIN-neo trial), thus the role of Therapeutic Lymph Node Dissections (TLND) in patients with major pathologic responses (MPR: pathological (near) complete response) is now unclear. In the PRADO trial, TLND was omitted in patients with MPR in their index lymph node ((ILN), the largest LN marked prior to neoadjuvant therapy). We sought to determine if less extensive surgery is associated with better Health Related Quality of Life (HRQoL). These are the first results of the comparison of HRQoL between patients undergoing a TLND or less extensive ILN excision. Methods: HRQoL was assessed with the European Organisation for Research and Treatment of Cancer QoL questionnaire-C30 (QLQ-C30). A generalized estimation equation was used to assess the difference in HRQoL outcomes between patients who underwent TLND (pathological non- and partial-responders, pNR/pPR) versus those who did not (pathological (near)complete responders, pNCR/pCR). Differences were adjusted for age, gender and follow-up (FU, in weeks), but not for pathological responses (pNR, pPR, pNCR &amp; pCR). Differences in QLQ-C30 scores were classified as clinically important according to published guidelines. Results: A total of 49 patients from the PRADO study had reached at least 24 weeks FU, and were included in the first explorative analysis. The median age of this study population was 58 years (range, 22-84). Questionnaire completion rates were high: 94% at baseline, 100%, 90%, 88% at week 6, 12 and 24, respectively. Sixteen (33%) patients underwent TLND versus 33 (67%) who had ILN excision only. Over a FU period of 24 weeks, patients who underwent TLND scored significantly lower on global (68 vs 78, adjusted difference (diff) = -9.53, p = .005), physical (84 vs 94 diff = -11.1, p = &lt; .001), emotional (69 vs 83, diff = -11.7, p = .001), role (70 vs 85, diff = -13, p = .004), and social functioning (81 vs 91, diff = -8.9, p = .016) and had a higher symptom burden of fatigue (35 vs 23, diff = 11.1, p = .004), insomnia (38 vs 18, diff = 16.6, p = .002) and financial impact (12 vs 4, diff = 7.9, p = .027) than patients undergoing ILN excision only. These differences were indicated as clinically relevant. Conclusions: First results from PRADO suggest that reducing the extent of surgery following neoadjuvant immunotherapy might result in better HRQoL of high-risk stage III melanoma patients. Clinical trial information: NCT02977052.

Optimal timing for prediction of pathologic complete response to neoadjuvant chemoradiotherapy with diffusion-weighted MRI in patients with esophageal cancer

ObjectiveThis study was conducted in order to determine the optimal timing of diffusion-weighted magnetic resonance imaging (DW-MRI) for prediction of pathologic complete response (pCR) to neoadjuvant chemoradiotherapy (nCRT) for esophageal cancer.MethodsPatients with esophageal adenocarcinoma or squamous cell carcinoma who planned to undergo nCRT followed by surgery were enrolled in this prospective study. Patients underwent six DW-MRI scans: one baseline scan before the start of nCRT and weekly scans during 5 weeks of nCRT. Relative changes in mean apparent diffusion coefficient (ADC) values between the baseline scans and the scans during nCRT (ΔADC(%)) were compared between pathologic complete responders (pCR) and non-pCR (tumor regression grades 2–5). The discriminative ability of ΔADC(%) was determined based on the c-statistic.ResultsA total of 24 patients with 142 DW-MRI scans were included. pCR was observed in seven patients (29%). ΔADC(%) from baseline to week 2 was significantly higher in patients with pCR versus non-pCR (median [IQR], 36% [30%, 41%] for pCR versus 16% [14%, 29%] for non-pCR, p = 0.004). The ΔADC(%) of the second week in combination with histology resulted in the highest c-statistic for the prediction of pCR versus non-pCR (0.87). The c-statistic of this model increased to 0.97 after additional exclusion of patients with a small tumor volume (< 7 mL, n = 3) and tumor histology of the resection specimen other than adenocarcinoma or squamous cell carcinoma (n = 1).ConclusionThe relative change in tumor ADC (ΔADC(%)) during the first 2 weeks of nCRT is the most predictive for pathologic complete response to nCRT in esophageal cancer patients.Key Points• DW-MRI during the second week of neoadjuvant chemoradiotherapy is most predictive for pathologic complete response in esophageal cancer.• A model including ΔADCweek 2was able to discriminate between pathologic complete responders and non-pathologic complete responders in 87%.• Improvements in future MRI studies for esophageal cancer may be obtained by incorporating motion management techniques.

Diamonds in the rough: An analysis of complete pathologic responders in ovarian cancer

Diamonds in the rough: An analysis of complete pathologic responders in ovarian cancer

Improved prognosis with induction chemotherapy in pathological complete responders after trimodality treatment for esophageal squamous cell carcinoma: Hypothesis generating for adjuvant treatment

PurposeTo compare the locations of recurrences and survival outcomes in esophageal squamous cell carcinoma (ESCC) patients with pathological complete response (pCR) after neoadjuvant concurrent chemoradiotherapy (CCRT) with or without preceding induction chemotherapy (IC) followed by esophagectomy. MethodsAmong 276 patients with locally advanced ESCC undergoing trimodality treatment during 2004–2014, 94 (34.1%) with pCR were eligible. The cohort included 26 patients undergoing IC before CCRT (IC group), and 68 patients who did not receive IC (non-IC group). ResultsAt a median follow-up of 51.4 months (95% confidence interval; 42.9–62.1), 19 patients experienced recurrences. There was a trend toward fewer distant failures in the IC group (0% vs.14.7%, p = 0.057), while locoregional recurrence was similar (7.7% vs. 7.4%). IC was associated with significantly improved survivals with the 5-year RFS and OS rates for the IC group of 85.1% and 90.5%, respectively, compared to of 46.2% and 48.1% for the non-IC group (p = 0.008 for RFS, and p = 0.015 for OS). By multivariable analyses, IC remained the only significant factor associated with survivals (HR:0.18 for RFS, p = 0.020 and HR:0.18 for OS, p = 0.025). The effect of IC in the whole cohort, irrespective of pathological response, was also assessed. Patients with non-pCR in the IC group had a trend toward worse survivals compared to the non-IC group ConclusionsIn ESCC patients with pCR after trimodality treatment, IC was associated with favorable survivals. The benefits of IC might be a hypothesis generation for adjuvant treatment for patients with pCR.

Neoadjuvant therapy duration and outcome of patients with resectable and borderline resectable pancreatic ductal adenocarcinoma (PDAC).

436 Background: Neoadjuvant chemotherapy (NA CT) may improve surgical selection for resectable (R) PDAC, and margin negative resection in borderline resectable (BR) PDAC. Optimal duration of NA CT is unknown, as is the role of XRT with modern chemotherapy. We compared survival outcomes by duration of NA CT and NA CT + XRT. Methods: Patients with R or BR PDAC who underwent NA CT with or without XRT and followed by curative resection were included in this analysis. Data was extracted from an IRB approved pancreatic cancer database at Indiana University. Disease Free (DFS) and Overall (OS) survival were calculated from the surgery date and compared between: 1) &lt; 3 v ≥ 3 months NA CT and 2) NA CT with/without XRT. Results: Between Summer 2008 and Summer 2018, 116 patients received NA CT with or without XRT and completed surgical resection. Median (range) age was 63 years (36, 84), stages were R=47%, BR=53%. Most patients received modified FOLFIRINOX or FOLFIRINOX (59 %), or gemcitabine/nab-paclitaxel (13%) and 24% received XRT. There were four (3 %) pathologic complete responders, all in the ≥ 3 mo NA CT + XRT group. Percent node positive was lower in NA CT + XRT versus NA CT only (median 0% vs 7.4%, p &lt; 001), but did not differ by duration of NA CT. With a median (range) follow-up time of 13.7 mo (0.7, 83.0), median OS was 22.5 mo (19.5, 29.8) with &lt; 3 mo NA CT versus 16.3 (12.2, 18.9) with ≥ 3 mo NA CT (p = 0.02) and was 22.6 mo (17.0, 82.9) with NA CT + XRT versus 19.5 (13.1, 22.5) in NA CT only (p = 0.03). There was no difference in DFS by duration of NA CT or XRT. Conclusions: In this study, patients who received a shorter course of chemotherapy and radiation had improved mOS when calculated from the surgery date. While this unexpected results could reflect selection bias of therapy, further analysis will account for tumor stage at diagnosis, perioperative complications and use propensity score adjustment to examine/adjust for possible treatment selection bias.