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. One hundred twelve patients with 117 sites of locally recurrent cancer receiving carbon ion radiotherapy were analyzed. Fifty relapses originated in the presacral region, 38 in the pelvic sidewalls, 16 in the perineal region and 8 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 90 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 local control rate in patients treated with 73.6 GyE in the present study was 94% at three years and 94% at 5 years. Dose escalation was then halted at this level. The median survival time in patients treated with 73.6 GyE was 54 months (range, 7 to 65 months), and the 3- and 5-year overall survival rates were 72% at 3 years and 40% at 5 years, 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)