A phase II study of preoperative mFOLFOX6 with short-course radiotherapy in patients with locally advanced rectal cancer and liver-only metastasis

Background and purpose To evaluate the efficacy and safety of upfront mFOLFOX6 followed by short-course radiotherapy (SCRT) and surgery in patients with locally advanced rectal cancer and liver-only metastases. Materials and methods This single-arm phase II study involved 32 patients. mFOLFOX6 was administered for four cycles followed by SCRT and another four cycles of mFOLFOX6. Surgery was performed 4-6 weeks after the last chemotherapy cycle. The primary endpoint was complete (R0) resection rate. Secondary endpoints were response rate, progression-free survival (PFS), overall survival (OS), and complication rates. Results Surgical resection of the rectum and liver was performed in 25 patients (78%) and R0 resection was achieved in 20 patients (63%). Local tumor downstaging was observed in 54% of patients. Median OS and PFS were 38 and 9 months, respectively. One patient discontinued treatment due to toxicity and no treatment-related deaths occurred. Patients who progressed after 4 cycles of mFOLFOX6 were less likely to receive resection. Conclusions This regimen was safe and effective in inducing local tumor response and achieving R0 resection in this patient population.