A prospective feasibility study of uracil-tegafur and leucovorin as adjuvant chemotherapy for patients aged ≥ 80 years after curative resection of colorectal cancer, the HiSCO-03 study

Purpose: There is no consensus on the safety and effectiveness of adjuvant chemotherapy for patients with stage III colorectal cancer (CRC) aged ≥ 80 years. We conducted a prospective multi-institutional phase II study of uracil-tegafur and leucovorin (UFT/LV) as adjuvant chemotherapy in this population.

Patients and methods: Patients with stage III CRC aged ≥ 80 years who underwent curative resection were enrolled. Eligible patients received UFT/LV therapy (UFT, 300 mg/m² per day as tegafur; LV, 75 mg/day on days 1-28, every 35 days for five courses). Primary endpoint was feasibility, and secondary endpoints were safety and relative dose intensity.

Results: Sixty-nine patients were enrolled between 2013 and 2021. Of the 69 patients, 65 were included in the analysis. There were 32 males and 33 females with a median age of 82 years (range 80-88 years). In the primary endpoint, administration completion rate was 67.3% (95% confidence interval 54.9-77.6%), and the lower limit of the 95% confidence interval was below the threshold of 60%. 21 patients discontinued treatment because of adverse events (AEs) and refused treatment. The median relative dose intensities were 84% (range 4-100%) for UFT, and 100% (range 4-100%) for LV. Incidence of grade three or higher AEs were neutropenia (1.5%), aspartate transaminase elevation (3%), alanine transaminase elevation (1.5%), oral mucositis (3%), anemia (1.5%), and diarrhea (4.6%).

Conclusions: The indications for adjuvant UFT/LV therapy for elderly CRC aged ≥ 80 years were considered limited. It is necessary to clarify the background of patients in whom drug administration is discontinued and investigate their impact on long-term prognosis.