Radiation Therapy Patterns of Care in Gastric Adenocarcinoma: A Single-Institution Experience

Abstract

Gastric adenocarcinoma (GAC) is one of the most commonly diagnosed cancers worldwide. The two standard approaches for treatment of resectable advanced gastric cancer are postoperative adjuvant 5-fluorouracil-based (5-FU) chemoradiation based on the Intergroup 0116 trial (INT-0116) or perioperative epirubicin, cisplatin, and 5-FU (ECF) chemotherapy based on the MAGIC (MRC Adjuvant Gastric Infusional Chemotherapy) trial. The most appropriate treatment strategy to decrease recurrence rates and improve survival remains controversial. The purpose of this study was to analyze the change in patterns of care in GAC patients treated at one institution after the 2006 Cunningham/MAGIC trial and secondarily describe recurrence patterns and survival outcomes. One hundred fifty patients were analyzed from a prospectively maintained database of patients who underwent resection for GAC between December 2000 and June 2013. The cohort was divided into patients treated between 2000-2006 (Early) and 2007-2013 (Late). Survival outcomes were calculated from the date of surgery to the date of last follow-up or the date of death from any cause. Clinicopathologic features of the two cohorts were analyzed by chi-square test for categorical variables and student’s t-test for continuous variables. Kaplan-Meier log-rank survival analysis was performed to evaluate association of the two cohorts with patient survival. The median follow-up for the entire cohort was 23.2 mos and the median OS was 40.9 mos. Patients receiving adjuvant radiation therapy was equivalent between the two cohorts (n = 23 vs n = 35, p = 0.21). Neoadjuvant chemotherapy alone increased from 2 patients in the Early cohort to 32 patients in the Late cohort (p<0.001). 86 patients in the Late cohort had D2 lymphadenectomy compared to 40 patients in the Early cohort (p = 0.002). Overall 3-year survival was 68.8% for the Late cohort and 43.6% for the Early cohort (p = 0.010). Overall recurrence rate was 25.3% with no difference in rates of recurrence between the two cohorts (30.4% vs 22.3%, p = 0.37). The number of patients who receive adjuvant chemoradiation has not changed significantly from pre-MAGIC to post-MAGIC; however, neoadjuvant chemotherapy has become more prevalent. In turn, overall 3-year survival in this GAC cohort has increased. The results of the study describe the benefits of neoadjuvant chemotherapy and D2 lymphadenectomy on GAC patient overall survival but demonstrate no effects on recurrence-free survival. New treatment approaches are prolonging survival but may be failing to target the subset of patients who are more likely to recur. As we begin to redefine treatment for GAC patients and integrate different treatment modalities, we hope to continue to improve the overall survival of our patients and lower recurrence rates.