Carbon-ion therapy for patients with locally recurrent rectal cancer

The rate of local recurrence for rectal cancer ranges from 10 to 40%. Patients with locally recurrent rectal cancer have low rates of subsequent local control and overall survival. To improve long-term local control and survival of locally recurrent rectal cancer, we have initiated a radiation dose-escalation trial using carbon ion beams. In this paper, 22 patients who were enrolled onto this study between April 2001 and February 2003 were analyzed. Criteria for trial eligibility were confirmation of locally recurrent rectal cancers without distant metastases by CT, MRI and PET findings. The dose was determined as 67.2 GyE (4.2 GyE per fraction) and escalated to 70.4 GyE (4.4 GyE) in 5% increments. All toxicities in the 22 patients were relatively few and mild in these patients. All patients completed the scheduled treatment course. Tumor response was evaluated in 21 patients. The overall tumor response rate (complete response (CR)+partial response (PR)) was 45%. The overall actual local control rates at one year were 70% and 100% at 67.2 GyE and 70.4 GyE respectively. The one and two year overall survival rate were 95.2% and 72.6% respectively. The above results substantiate the superior usefulness of heavy ion radiotherapy in the treatment of recurrent rectal cancer to conventional photon radiotherapy or combination with chemotherapy. (author)