Added radiotherapy does not improve gastric cancer survival

Last Updated: 2018-05-01

By Will Boggs MD

NEW YORK (Reuters Health) - Postoperative chemoradiotherapy after gastric cancer resection does not improve overall survival, compared with postoperative chemotherapy alone, according to results from the international CRITICS trial.

"We were impressed by the high quality of the surgery in this non-Asian trial," Dr. Edwin P. M. Jansen from Netherlands Cancer Institute, in Amsterdam, told Reuters Health by email. "This, in combination with effective preoperative chemotherapy, might have contributed to the equivalent outcome after either of both postoperative arms."

Postoperative chemoradiotherapy has been the standard treatment for gastric cancer in the U.S., based on a 2001 trial showing superior outcomes compared with surgery alone. Perioperative chemotherapy has also been shown to be beneficial, leaving the role of radiotherapy unclear.

Dr. Jansen and colleagues compared overall survival after postoperative chemoradiotherapy versus postoperative chemotherapy alone in their open-label randomized trial of 788 patients with resectable gastric cancer.

Potentially curative resection was achieved in 79% (310/393) of patients in the chemotherapy group and in 83% (326/395) of patients in the chemoradiotherapy group, the team reports in The Lancet Oncology, online April 9.

Around half of the patients in both groups (46% of the chemotherapy group and 50% of the chemoradiotherapy group) completed the allocated treatment as planned.

After a median follow-up of 61.4 months, 55% of patients in the chemotherapy group and 58% in the chemoradiotherapy group had died, with median overall survival of 43 months and 37 months, respectively. Neither of these differences was statistically significant.

Results were similar for event-free survival (median, 28 months with chemotherapy vs. 25 months with chemoradiotherapy).

Post-hoc subgroup analysis did not identify differences in age, histology, or tumor location that might favor one treatment over the other.

Postoperative adverse events differed little between the groups, although grade 3-4 non-febrile neutropenia occurred more frequently during postoperative chemotherapy (34%) than during postoperative chemoradiotherapy (4%). Treatment-related serious adverse events were reported in 16% of both groups.

"We now have two options in the postop treatment of gastric cancer, chemotherapy or chemoradiotherapy," Dr. Jansen said. "With upcoming subgroup analyses we hope to identify which treatment is most suitable for which category of patients (histological type, N-status, R0 or R1 resection, etc.)."

"The results of the CRITICS trial would suggest that changing to postoperative chemoradiotherapy is of no benefit," writes Dr. Trevor Leong from Peter MacCallum Cancer Center, in Melbourne, Australia, in a linked editorial. "However, there might be subsets of patients who might benefit more from chemoradiotherapy, and further studies planned by the investigators will investigate this question in more detail. Postoperative chemoradiotherapy should still be considered for appropriate patients who have not had any preoperative therapy."

"The major direction for chemoradiotherapy studies in gastric cancer should now focus on preoperative therapy, which has distinct biological and clinical advantages compared with postoperative therapy, including tumor downstaging with an increase in R0 resection, and better patient tolerability," he adds.

"Does CRITICS signal the end for chemoradiotherapy in resectable gastric cancer?" Dr. Leong wonders. "These initial results would suggest a limited role, at least in patients who have received preoperative chemotherapy. However, the final answer to this question will only be clarified after chemoradiotherapy has been adequately assessed in the optimal setting of preoperative therapy."

SOURCE: https://bit.ly/2rc2Zdh and https://bit.ly/2jlmICU

Lancet Oncol 2018.