Post-operative chemotherapy may be just as effective as chemoradiotherapy in patients with gastric cancer who have already undergone pre-operative chemotherapy, according to phase III data presented at the European Society for Medical Oncology (ESMO) 18th World Congress of Gastrointestinal Cancer (June 29 – July 2, 2016; Barcelona, Spain).
Peri-operative chemotherapy, where treatment is administered before and after surgery, are the current standard of treatment for gastric cancer; however, some studies have suggested that post-operative chemoradiotherapy alone may produce similar outcomes.
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In a clinical trial presented at the ESMO meeting, investigators enrolled 788 patients with stage Ib-IVa resectable gastric cancer, all of whom received pre-operative chemotherapy consisting of three courses of epirubicin, a platinum compound (cisplatin or oxaliplatin), and capecitabine.
After surgery, patients were randomized to a ‘standard’ arm of treatment that continued with another three courses of the same chemotherapy regime or assigned to receive chemoradiotherapy involving 45 Gy in 25 fractions combined with weekly cisplatin and daily capecitabine.
Investigators found that 5-year survival rates were 40.8% in the chemotherapy arm and 40.9% in the chemoradiotherpy arm, indicating an equivalent efficacy between the two options.
There was a higher incidence of grade 3 or higher hematological adverse events in the chemotherapy arm (44% vs 34%), but a higher incidence of gastrointestinal adverse events in the chemoradiotherapy arm (42% v 37%).
Additionally, while the quality of surgery was generally very high, 52% of patients in the chemotherapy arm and 47% of patients in the chemoradiotherapy arm did not start or complete their full treatment course.
Concluding, principal investigator Marcel Verheij, MD, PhD, Netherlands Cancer Institute, Amsterdam, said that he and his colleagues were surprised by the findings. They had originally expected to see better survival outcomes from the post-operative chemoradiotherapy arm compared with those who received peri-operative chemotherapy, but added that subgroup analysis may identify specific patient populations likely to benefit from either approach.
