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Background Examination of at least 16 lymph nodes (LNs) has been traditionally recommended during gastric adenocarcinoma resection to optimize staging, but the impact of this strategy on survival is uncertain. Because recent randomized trials have demonstrated a therapeutic benefit from extended lymphadenectomy, we sought to investigate the impact of the number of LNs removed on prognosis after gastric adenocarcinoma resection. Study Design We analyzed patients who underwent gastrectomy for gastric adenocarcinoma from 2000 to 2012, at 7 US academic institutions. Patients with M1 disease or R2 resections were excluded. Disease-specific survival (DSS) was calculated using the Kaplan-Meier method and compared using log-rank and Cox regression analyses. Results Of 742 patients, 257 (35%) had 7 to 15 LNs removed and 485 (65%) had ≥16 LNs removed. Disease-specific survival was not significantly longer after removal of ≥16 vs 7 to 15 LNs (10-year survival, 55% vs 47%, respectively; p = 0.53) for the entire cohort, but was significantly improved in the subset of patients with stage IA to IIIA (10-year survival, 74% vs 57%, respectively; p = 0.018) or N0-2 disease (72% vs 55%, respectively; p = 0.023). Similarly, for patients who were classified to more likely be "true N0-2," based on frequentist analysis incorporating both the number of positive and of total LNs removed, the hazard ratio for disease-related death (adjusted for T stage, R status, grade, receipt of neoadjuvant and adjuvant therapy, and institution) significantly decreased as the number of LNs removed increased. Conclusions The number of LNs removed during gastrectomy for adenocarcinoma appears itself to have prognostic implications for long-term survival.

Background Adjuvant immunotherapy has improved outcomes in patients with advanced melanoma; however, the potential benefit for patients with pancreatic ductal adenocarcinoma (PDAC) remains unknown. The aim of this study was to determine the impact of adjuvant chemotherapy and immunotherapy (CTx-IT) compared with CTx alone on patient survival after resection of PDAC. Study Design Patients who underwent resection of PDAC from 2004 to 2015 were identified from the National Cancer Database. Univariate and multivariate Cox proportional hazards models were used to determine predictors of overall survival (OS) based on the type of adjuvant therapy received. Patients who received adjuvant immunotherapy were compared with those who received adjuvant CTx alone by propensity score matching. Results Of 21,313 patients who received curative-intent resection for PDAC followed by adjuvant systemic therapy, 269 (1.3%) patients were treated with adjuvant CTx-IT. Propensity score matching resulted in a cohort of 477 patients: (229 CTx only and 248 CTx-IT). The 5-year OS was higher in the CTx-IT group compared with CTx alone (29.2% vs 18.3%; p = 0.0045). On multivariate analysis, the addition of adjuvant immunotherapy was associated was improved overall survival (hazard ratio 0.74; p = 0.007). Conclusions The addition of adjuvant immunotherapy to chemotherapy is associated with improved survival compared with chemotherapy alone after curative-intent resection of pancreatic adenocarcinoma. Future research is warranted to match specific immunotherapy agents with susceptible patient populations to improve outcomes for this aggressive disease.

Background Multi-institutional collaborations provide granularity lacking in epidemiologic data sets to enable in-depth study of rare diseases. For patients with superficial, high-grade soft tissue sarcomas of the trunk and extremity, the value of radiation therapy (RT) is not clear. We aimed to use the 7-institution US Sarcoma Collaborative (USSC) and the National Cancer Database (NCDB) to investigate this issue. Study Design All adult patients with superficial truncal and extremity high-grade soft tissue sarcomas who underwent primary curative-intent resection from 2000 to 2016 at USSC institutions or were included in the NCDB from 2004 to 2013 were analyzed. Propensity score matching was performed. End points were locoregional recurrence-free survival (LRFS), overall survival (OS), and disease-specific survival (DSS). Results Of 4,153 patients in the USSC, 169 patients with superficial high-grade tumors underwent primary curative-intent resection, 38% of which received RT. On multivariable Cox-regression analysis, RT was not associated with improved LRFS (p = 0.56), OS (p = 0.31), or DSS (p = 0.20). On analysis of 51 propensity score-matched pairs, RT was still not associated with increased LRFS, OS, or DSS. Analysis of 631 propensity score-matched pairs in the NCDB demonstrated improved 5-year OS rate associated with RT (80% vs 70%; p = 0.02). The LRFS and DSS rates were not evaluable. Conclusions Granular data afforded by collaborative research enables in-depth analysis of patient outcomes. The NCDB, although powered with large numbers, cannot assess many relevant outcomes (eg recurrence, DSS, or complications). In this study, the approaches yielded conflicting results. The USSC data suggested no value of radiation and the NCDB demonstrated improved OS, contradicting all randomized controlled trials in sarcoma. The pros and cons of either approach must be considered when applying results to clinical practice, and underscore the importance of randomized controlled trials.