Background: Limited data are available to guide management of patients with stage I–III gastric cancer not undergoing potentially curative surgical resection. We compared survival outcomes associated with chemotherapy alone versus chemoradiation (CRT) in the treatment of nonmetastatic gastric cancer. Methods: Patients with gastric adenocarcinoma from 2004 to 2015 were identified using the National Cancer Database. Patients were excluded if they had surgery, metastatic disease, or T0, Tis, or T1a disease. Logistic regression was used to evaluate predictors of CRT use. Cox proportional hazards modeling was performed to compare overall survival (OS) between chemotherapy alone and CRT in overall and propensity score–matched cohorts. Results: We identified 4,795 patients with stage I–III gastric adenocarcinoma who did not undergo surgery, at a median follow-up of 11.8 months. A total of 3,316 patients (69.2%) received chemotherapy alone and 1,479 patients (30.8%) received CRT. Predictors of increased CRT use were age ≥65 years (odds ratio [OR] 1.68; 95% CI, 1.43–1.99; P<.001), Charlson-Deyo comorbidity score ≥2 (OR, 1.46; 95% CI, 1.18–1.81), and treatment at a community facility (OR, 1.27; 95% CI, 1.07–1.51; P=.006). Patients receiving CRT had a 2-year OS rate of 28.3% compared with 21.5% among those receiving chemotherapy. Multivariate analysis showed that CRT was associated with improved OS (hazard ratio [HR], 0.82; 95% CI, 0.77–0.89; P<.001). After propensity score matching, a persistent survival benefit was observed (HR, 0.80; 95% CI, 0.74–0.88; P<.001). Conclusions: In patients with stage I–III gastric cancer not undergoing surgical resection, CRT was associated with improved survival compared with chemotherapy alone. However, only 30.8% of patients received CRT in this setting.
Richard Li, Wei-Hsien Hou, Joseph Chao, Yanghee Woo, Scott Glaser, Arya Amini, Rebecca A. Nelson, and Yi-Jen Chen
Louisa Liu, Yanghee Woo, Massimo D’Apuzzo, Laleh Melstrom, Mustafa Raoof, Yu Liang, Michelle Afkhami, Stanley R. Hamilton, and Joseph Chao
Despite the use of first-line therapies like fluoropyrimidine and platinum-based cytotoxic chemotherapy, gastric cancer (GC) continues to carry a poor prognosis. Recent subgroup analyses of first-line phase III trials have demonstrated that patients with microsatellite instability–high (MSI-H) metastatic GC derive significant improvement in survival rates when immune checkpoint inhibitors (ICIs) are combined with chemotherapy compared with chemotherapy alone. However, it remains to be seen whether the success of ICIs in the metastatic setting can be translated into earlier stages of GC with resectable disease. We report 6 cases of locally advanced, nonmetastatic MSI-H GC that all demonstrated favorable response following treatment with pembrolizumab in addition to neoadjuvant chemotherapy. With the exception of immune-related colitis in one patient, pembrolizumab was well-tolerated. To our knowledge, this is the first reported US case series of patients treated with an ICI in combination with neoadjuvant chemotherapy for advanced, nonmetastatic, resectable or unresectable MSI-H GC.