The rationale of postoperative chemoradiotherapy after preoperative chemotherapy is to combine systemic and locoregional treatments to reduce the risk of recurrent disease and improve outcomes.— Marcel Verheij, MD, PhD
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Postoperative treatment intensification with chemoradiotherapy does not achieve better outcomes when compared with postoperative chemotherapy in patients with gastric cancer who have already undergone preoperative chemotherapy, according to phase III data presented by Marcel Verheij, MD, PhD, et al at the ESMO (European Society for Medical Oncology) 18th World Congress on Gastrointestinal Cancer in Barcelona.1
“The rationale of postoperative chemoradiotherapy after preoperative chemotherapy is to combine systemic and locoregional treatments to reduce the risk of recurrent disease and improve outcomes,” said the study’s principal investigator Dr. Verheij, of the Netherlands Cancer Institute.
Perioperative (pre- and postoperative) chemotherapy is the current standard of treatment for gastric cancer, but previous studies have suggested that postoperative chemoradiotherapy alone may improve outcomes to a similar extent.
In this phase III study, 788 patients with stage Ib–IVa resectable gastric cancer were randomized upfront and were all given preoperative chemotherapy, which consisted of three courses of epirubicin, a platinum compound (cisplatin or oxaliplatin), and capecitabine. After surgery, patients randomized to the “standard” arm continued with another three courses of the same chemotherapy regimen, whereas the others received chemoradiotherapy involving 45 Gy in 25 fractions combined with weekly cisplatin and daily capecitabine.
Researchers found a 5-year survival rate of 40.8% in the chemotherapy arm and 40.9% in the chemoradiotherapy arm, showing equivalent efficiency between the two treatment options.
There was a higher incidence of grade 3 or higher hematologic adverse events in the chemotherapy arm (44% vs 34%) but a higher incidence of gastrointestinal adverse events in the chemoradiotherapy arm (42% vs 37%).
Although the surgical quality was very high in the study, researchers noted that a significant number of patients did not start or complete the full course of either chemotherapy or chemoradiotherapy: 52% in the chemotherapy arm and 47% in the chemoradiotherapy arm.
Dr. Verheij said the team had anticipated a better outcome from the postoperative chemoradiotherapy arm compared with the perioperative chemotherapy arm, but he said subgroup analyses may identify specific patient populations who will benefit from either approach. ■
1. Verheij M, Cats A, Jansen EPM, et al: A multicenter randomized phase III trial of neo-adjuvant chemotherapy followed by surgery and chemotherapy or by surgery and chemoradiotherapy in resectable gastric cancer: First results from the CRITICS study. ESMO World Congress on Gastrointestinal Cancer. Abstract LBA-02. Presented June 30, 2016.