[Two cases of intrapelvic recurrence after radical resection of rectal cancer, treated with carbon ion radiotherapy].

We report two cases of intrapelvic recurrence after radical resection of rectal cancer, which were successfully treated with Carbon Ion Radiotherapy (C-ion RT). The first case is of a 71-year-old man who underwent abdominoperineal resection (APR) with D2 lymphadenectomy for rectal cancer in December 2010, followed by adjuvant chemotherapy with S-1 plus oxaliplatin. The patient was diagnosed with a recurrence on the left pelvic wall in August 2012, and underwent C-ion RT (73.6 Gray equivalent) for this lesion in October 2012. Three months after this treatment, the lesion had regressed significantly, as ascertained by computed tomography (CT). He remains alive with no signs of recurrence. The second case is of a 63-year-old man who underwent APR with D3 lymphadenectomy for rectal cancer, followed by adjuvant chemotherapy with uraciltegafur ( UFT). The patient was diagnosed with a recurrence on the right pelvic wall in January 2013, and underwent C-ion RT (73.6 Gray equivalent) for this lesion in March 2013. Three months after this treatment, the lesion reduced significantly, and the patient is alive with no signs of recurrence. Although the long-term outcomes need to be assessed, C-ion RT could be a safe and effective therapy.