Intraoperative radiation therapy for locally advanced primary and recurrent colorectal cancer: Ten-year institutional experience

Background We evaluated the role of intraoperative radiation therapy (IORT) during radical resection of locally advanced colorectal cancer (CRC). Methods We retrospectively evaluated all patients with CRC treated with IORT at our institution from 2001 to 2010. IORT was delivered using high-dose-rate brachytherapy (median 12.5-Gy). We analyzed factors associated with postoperative morbidity, local control (LC), and overall survival (OS). Results One hundred patients were evaluated with 70% received IORT for recurrent tumors. R0 resection rate was 58%. Postoperative Grade ≥3 complications (33%) were independently associated with transfusions ≥3 units packed red blood cells (P = 0.016) and body mass index (BMI) ≥35 (P = 0.0499). Eighty-two patients underwent external beam radiation therapy (EBRT) before IORT. Five-year LC was 94%, for primary and 56%, for recurrent tumors, respectively (P = 0.007). Microscopic positive (R1) margins were not associated with LC (P = 0.316). BMI ≥30 (P = 0.048) and post-discharge complications (P = 0.041) were independent risk factors for worse LC. Median post-IORT OS was 67.7 (95% CI 51.1-84.3) months for all patients. Conclusion For patients with primary or recurrent locally advanced CRC, treatment with radical surgery and IORT achieved excellent LC outcomes irrespective of microscopic margin status. IORT may be indicated for tumors suspected to have close or positive microscopic margins.