[Irradiation with carbon ions for locally recurrent rectal cancer]

A female patient in her 70s underwent an abdominoperineal resection and bilateral lymph node dissection for advanced lower rectal cancer. The patient did not receive neoadjuvant therapy. In the Japanese classification of colorectal carcinoma (8th Edition), the tumor was a moderately differentiated type 2 adenocarcinoma, and was 4.5 cm in size. Histologically, the tumor was considered to be Stage IIIb (T3N0M0). She received no adjuvant chemotherapy. After 39 months, pelvic computed tomography (CT ) revealed a 29 mm tumor in the right pelvic wall. The patient declined surgery for recurrence so radiotherapy was planned. First, chemotherapy with mFOLFOX6 was administered for 4 courses to reduce tumor size. Consequently, irradiation with carbon ions was given to the site of recurrence at a total dose of 74 GyE in 37 fractions. There were no severe complications. Carcinoembryonic antigen (CEA) level decreased to the lower limit of the normal range from a maximum of 4.9, and no progression of the recurrent tumor was detected on CT for approximately 4 years. Systemic chemotherapy followed by irradiation with carbon ions may be effective for recurrent rectal cancer.