Intratumoral Fusobacterium predicts aggressive colorectal cancer and poor chemotherapy response

Intratumoral Fusobacterium in colorectal cancer signals a more aggressive subtype, with weaker immune response, limited adjuvant chemo benefit, and higher recurrence risk, a multicenter study reports. In the FUSOMAP study of 740 resectable colorectal cancer patients, 21% had Fusobacterium-positive tumors. At 48.6 months median follow-up, these patients had shorter recurrence-free and disease-free survival; adjuvant chemotherapy helped only Fusobacterium-negative patients. Fusobacterium persisted in stool up to three years before relapse in some patients. Authors say findings need prospective validation in larger cohorts before clinical application.