Chronomodulated capecitabine and adjuvant radiation in intermediate-risk to high-risk rectal cancer: a phase II study

The aim of this study was to evaluate the feasibility and tolerability of capecitabine administration according to a specific time schedule, combined with adjuvant radiation therapy, in intermediate-risk to high-risk rectal cancer patients treated with an upfront surgery. The primary endpoint was the rate of grade 3 to 4 diarrhea during chemoradiation (CRT).

Stage II and III rectal cancer patients received, after total mesorectal excision, 2 cycles of XELOX regimen (oxaliplatin 130 mg/m(2) on day 1; capecitabine 1000 mg/m(2) bid on day 1 to 14, q21), followed by capecitabine (800 mg/m(2) bid daily; 20% dose at 12:00 AM and 80% dose at 12:00 PM) administered continuously during pelvic radiation (total 50.4 Gy in 28 fractions, 1.8 Gy daily dose between 2:00 and 4:00 PM). Four additional cycles of XELOX were administered after chemoradiotherapy.

Fifty-one radically resected rectal cancer patients were enrolled. All, but one, cases were evaluated for safety of CRT. We reported a grade 3 and 4 diarrhea rate of 14% (7 of 50 patients), whereas no grade 3 and 4 leukopenia was observed. Grade 1 and 2 proctitis was observed in 26 (52%) cases, whereas grade 1 and 2 cystitis in 5 (10%) patients. Only 2 cases of grade 3 proctitis and cystitis were reported, respectively. The CRT phase was feasible and was completed by 43 (84%) patients. Three patients developed actinic enteritis 60 days after the end of the radiotherapy program.

Capecitabine timetable administration combined with adjuvant radiation therapy of rectal cancer is well tolerated and feasible. Further investigation of this chronomodulated schedule in terms of efficacy is warranted in neoadjuvant setting.