Carbon ion therapy for patients with locally recurrent rectal cancer

The purpose of this study was to evaluate the tolerance for and effectiveness of carbon ion radiotherapy in patients with locally recurrent rectal cancer. We conducted a phase I/II dose escalation study of carbon ion radiotherapy. Fifty-five patients with 59 sites of locally recurrent cancer received carbon ion radiotherapy. Twenty-three relapses originated in the presacral region, 16 in the pelvic side walls, 14 in the perineal region and 6 in the colorectal anastomosis. The total dose ranged from 67.2 to 73.6 gray equivalent (GyE) and was administered in 16 fixed fractions over 4 weeks (4.2 to 4.6 GyE/fraction). None of 32 patients treated with the highest total dose of 73.6 GyE experienced National Cancer Institute-Common Toxicity Criteria grade 3 to 5 acute reactions. The overall local control rates were 92% at 1 year and 79% at 3 years of follow-up. Dose escalation was then halted at this level. The median survival time was 38 months (range, 7 to 52 months), and the 1- and 3-year overall survival rates were 91% and 65%, respectively. Carbon ion radiotherapy seems to be a safe and effective modality in the management of locally recurrent rectal cancer, providing good local control and offering a survival advantage without unacceptable morbidity. (author)