5 x 5 Gy, Consolidation Chemotherapy Slightly Superior for cT4 or Fixed cT3 Rectal Cancer

Long-course oxaliplatin-based preoperative chemoradiation vs 5 x 5 Gy and consolidation chemotherapy were similarly efficacious in patients with cT4 or fixed cT3 rectal cancer, however improved overall survival and lower acute toxicity were associated with the 5 x 5 Gy arm, according to a study published in the Annals of Oncology.¹

Improvements in local control are needed when using preoperative chemoradiation for cT4 or advanced cT3 rectal cancer and in this trial, investigators sought to explore more effective schedules.

A total of 515 patients with fixed cT3 or cT4 were randomly assigned to receive 5 x 5 Gy and 3 cycles of FOLFOX4 (fluorouracil, leucovorin, oxaliplatin; group A; n = 261) or to 50.4 Gy in 28 fractions combined with two 5-day cycles of bolus 5-fluorouracil  325 mg/m²/day and leucovorin 20 mg /m²/day during the first and fifth week of irradiation along with 5 infusions of oxaliplatin 50 mg/m² once a week (group B; n = 254).

The study’s primary endpoint was RO resection rates, which were 77% in group A and 71% in group B (P = .07). Pathological complete response rates were 16% vs 12% (P = .17).

At 3 years, overall survival and disease-free survival were 73% vs 65% (P = .046) and 53% vs 52% (P = .85), respectively. Cumulative incidence of local failure and distant metastases were 22% vs 21% (P = .82) and 30% vs 27% (P = .26). Postoperative and late complication rates were 29% in group A and 25% in group B (P = .18) and 20% vs 22%, respectively (P = .54).

Reference

1. Bujko K, Wyrwicz L, Rutkowski A, et al. Long-course oxaliplatin based preoperative chemoradiation vs. 5 x 5 Gy and consolidation chemotherapy for cT4 or fixed cT3 rectal cancer: results of a randomised phase III study [published online ahead of print February 15, 2016]. Ann Oncol. doi: 10.1093/annonc/mdw062.