Survival and Recurrence Patterns in Patients With Stomach Adenocarcinoma Receiving Chemotherapy or Chemoradiotherapy After D2 Gastrectomy in a Tertiary Care Cancer Institute: A Retrospective Real-World Evidence Cohort Study

Abstract

Clinical trials comparing the efficacy of adjuvant chemotherapy (CT) and chemo radiation therapy (CTRT) for stomach adenocarcinoma have reported equivocal results. Hence, the current retrospective cohort study assessed the long-term survival and recurrence outcomes of these therapies, to generate evidence in a real-world scenario. Pathologically confirmed patients with stomach adenocarcinoma aged ≥18 years who underwent gastrectomy and D2 lymph nodal dissection at a tertiary cancer hospital from January 2010 to October 2017 were enrolled. Hospital-based follow-up was performed until December 2021. Data were gathered from electronic medical records, supplemented by telephonic interviews for patients who could not come for physical follow-up. CT-alone and CTRT cohorts were compared in terms of survival and recurrence outcomes. The analysis included 158 patients (mean age, 56.42 years; 63.9% male; CT-alone cohort, 69; CTRT cohort, 89). Patients in the CTRT cohort had significantly worse tumor characteristics at baseline (29.2% had the diffuse type of tumor, 94.4% had stage II or III, 68.5% had lympho-vascular space invasion, and 85.4% had lymph node involvement). Recurrence was observed in 13 (19.7%) of the 76 followed-up patients. Although locoregional recurrence was higher in the CT-alone cohort (7 vs 2), distant metastasis was higher in the CTRT cohort (3 vs 1). The overall 5-year survival was 67.0% (SE, 5.0%) and 5-year recurrence-free survival (RFS) was 75.0% (SE, 5.0%). On multivariate Cox regression, no variable was significantly associated with the overall survival, whereas age, positive lymph nodes without extracapsular extension, and lymph node-negative were significantly associated with RFS. The CTRT cohort had significantly (84.0%) higher RFS (hazard ratio, 0.161; 95% CI, 0.056-0.464; P < .001). Patients who received adjuvant CTRT after D2 dissection showed similar overall survival but significantly higher RFS than the CT-alone cohort, despite having worse baseline tumor characteristics.