Results
The median follow up was 6.5 years. There were no significant differences between the surveillance groups with regard to 5-year overall survival (P = .340) or recurrence-free survival (P = .473).
There were no significant differences in recurrence-free or overall survival when patients were stratified by age, sex, stage, CEA at a cut point of 5 mcg/L, and primary tumor characteristics including location, perineural invasion, and occlusion/perforation.
There were 356 recurrences in patients initially treated for colon cancer. CEA surveillance with or without CT scan was associated with an increased incidence of secondary resection with curative intent. The rate of secondary resection was 66.3% in the standard imaging with CEA arm, 59.5% in the CT plus CEA arm, 50.7% with CT imaging but no CEA, and 40.9% with standard imaging and no CEA (P = .0035).
The rates were similar among the 83 patients with recurrence after initial treatment for rectal cancer, but the between-arm differences were not significant. The rate of secondary resection with curative intent was 57.9% in the standard imaging with CEA arm, 47.8% in the CT plus CEA arm, 55% with CT imaging but no CEA, and 42.9% with standard imaging and no CEA.
The research is ongoing, and the team expects to report on secondary outcomes and ancillary studies of circulating tumor DNA, among other things, in 2021.
The study is being funded by the Federation Francophone de Cancerologie Digestive. Dr. Lepage disclosed ties with Novartis, Amgen, Bayer, Servier, and AAA. Dr. Price disclosed institutional research funding from Amgen and being an uncompensated adviser to Pierre-Fabre and Merck.
SOURCE: Lepage C et al. ESMO 2020, Abstract 398O.