Benefits of adjuvant chemotherapy shown in resected gastroesophageal cancer
medwireNews: Research suggests that adjuvant chemotherapy may improve survival over postoperative observation following preoperative chemoradiotherapy and curative-intent resection in patients with gastroesophageal adenocarcinoma.
“Our findings have important implications for the postoperative treatment of this patient group for which few data are available,” Matthew Porembka and colleagues, from the University of Texas Southwestern Medical Center in Dallas, USA, remark.
Using the US National Cancer Database, Porembka and team identified 10,086 adults (mean age 61 years, 88% men) with clinical stage T1N1-3M0 or T2-4N0-3M0 adenocarcinoma of the distal esophagus or gastric cardia who were treated with preoperative chemoradiotherapy and curative-intent resection.
Of these, just 8% received adjuvant chemotherapy after preoperative chemoradiotherapy and resection; these patients had more high-risk disease features than patients who underwent postoperative observation, including more advanced disease stage, greater positive resection margin rate, and lower rates of pathologic complete response.
To assess the impact of adjuvant chemotherapy on overall survival, the researchers matched 732 patients in the adjuvant chemotherapy group to 3660 patients in the postoperative observation group using the propensity score method, which included variables such as age, sex, race/ethnicity, comorbidity, insurance type, time from diagnosis to resection, clinicopathologic features, length of stay, and 30-day unplanned readmissions.
They report in JAMA Oncology that patients in the adjuvant chemotherapy group had significantly better overall survival than those in postoperative observation group, at a median of 40 months versus 34 months, and a hazard ratio of 0.79 in favor of adjuvant chemotherapy.
After 1 year, 94% of patients in the adjuvant chemotherapy group were still alive, compared with 88% in the observation group, and the corresponding survival rates at 3 and 5 years were 54% versus 47% and 38% versus 34%, respectively.
Further analyses showed that the survival benefit of adjuvant chemotherapy over postoperative observation was consistent across most patient subgroups, and was greatest in patients with a pathologic complete response, which Porembka et al say is “a relevant finding given that this patient group has a 23% risk of recurrence.”
The team also performed sensitivity analyses to quantify the effect of postoperative complications. They found that, unless the complication rate was extremely high (50%) in the postoperative observation group and extremely low (5%) in the adjuvant chemotherapy group, such complications would have little impact on the treatment effect of adjuvant chemotherapy.
The authors conclude: “These findings, while not confirmatory, provide compelling motivation to explore the potential benefit of adjuvant chemotherapy in a randomized clinical trial.”
By Laura Cowen
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