Reirradiation to the pelvis for recurrent rectal cancer

Objectives This study investigated late toxicity and infield progression-free survival in patients with locally recurrent rectal cancer (LRRC) who had previously received irradiation to the pelvis. Methods Twenty-two patients were treated by reirradiation to the pelvis between January 2000 and August 2007. All patients received curative surgery with preoperative or postoperative chemoradiotherapy as an initial treatment. Five patients (23%) underwent surgical resection after reirradiation. The median follow-up duration was 20 months (range, 7-91 months). Results Two patients (9%) had grade-3 acute toxicity and eight patients (36%) had grade-3 to -4 late toxicity. The incidence of grade-3 to -4 late toxicity in the gastrointestinal and urinary system was 18% and 27%, respectively. Recurrent tumor location (axial or anterior) and surgical resection after reirradiation significantly influenced severe late toxicity (P=0.024 and P=0.039, respectively). In the 17 patients not undergoing surgery after reirradiation, median infield progression-free survival was 16 months. Reirradiation doses exceeding 50Gy_αβ10 (equivalent dose in 2Gy fractions) significantly increased the infield progression-free survival (P=0.005). Conclusions Tumor location (axial or anterior) and surgery after reirradiation may increase severe late toxicity. In addition, an EQD2 exceeding 50Gy_αβ10 may improve infield control.