Chemotherapy-Only Neoadjuvant Strategy in High-Risk Rectal Cancer- BJS Open Feb.26

This multicentre phase II Japanese trial evaluated a chemotherapy-only neoadjuvant approach—FOLFOXIRI plus bevacizumab without radiotherapy—for MRI-defined high-risk locally advanced rectal cancer (LARC).

Thirty-one patients with at least one high-risk feature (cT4 disease, mesorectal fascia involvement, extramural vascular invasion, or lateral pelvic lymph node metastasis) received four cycles of FOLFOXIRI plus bevacizumab followed by two cycles of FOLFOXIRI before total mesorectal excision.

All patients proceeded to surgery. The pathological complete response (pCR) rate was modest at 10%, but the R0 resection rate was high (97%), indicating strong local resectability. At a median follow-up of nearly 3 years, local recurrence was low (3%), with 3-year recurrence-free survival and overall survival of 73% and 81%, respectively.

Toxicity was manageable: grade ≥3 neutropenia occurred in 29%, and grade ≥III postoperative complications in 23%, including 7% anastomotic leak. Notably, no gastrointestinal perforations were observed.

Although the pCR rate was lower than that of typical chemoradiotherapy-based regimens, the study suggests that intensive systemic chemotherapy may achieve good local control in selected high-risk patients. This strategy could be considered in patients unsuitable for pelvic radiotherapy, but larger comparative trials are needed before broader adoption.