Do rectal cancer patients with PIK3CA mutations benefit from preoperative radiotherapy with regard to local recurrences?

摘要

Preoperative radiation (PRT) significantly reduces local recurrences (LR) in rectal cancer. Identifying patients at risk for LR allows for refinement in patient selection for PRT. We previously demonstrated a PIK3CA mutation prevalence of 7.9% in rectal cancer and a strong association with increased risk of LR in nonirradiated stage I to III rectal cancer patients (5-year risks, 27.8% vs 9.4%; P = 0.006) from the total mesorectal excision (TME) trial (1), in which resectable rectal cancer patients were randomized for TME surgery only or short-term PRT (5x5 Gy) followed by surgery (2). We have now performed further analysis in the irradiated patients to investigate whether PIK3CA mutant patients benefit from PRT in preventing LR.