Patterns of Local Recurrence and Oncologic Outcomes in T3 Low Rectal Cancer (≤5cm from the Anal Verge) Treated With Short-Course Radiotherapy With Delayed Surgery : Outcomes in T3 Low Rectal Cancer Treated With Short-Course Radiotherapy With Delayed Surgery.

Abstract

Short-course radiotherapy with delayed surgery (SRT-delay) is still under clinical investigation for its efficacy in treating low rectal cancer (≤5cm from the anal verge). This study was designed to assess the pattern of local recurrence and oncologic outcomes in T3 low rectal cancer treated with SRT-delay. This study enrolled T3 low rectal cancer patients without distant metastasis between 2003 and 2015. All patients received total mesorectal excision following SRT-delay (25Gy/10 fractions/5days+S-1 radiosensitizer with a 4-week delay of surgery). The median follow-up period was 69 (range 1-149) months. A total 119 consecutive patients had low rectal cancer; 104 (87.4%) underwent intersphincteric resection (ISR), and 15 (12.6%) underwent abdominoperineal resection (APR). Fifty-six patients (47.1%) were ypT-downstaged, 86 (72.2%) were ypN0, and 10 (8.4%) had circumferential resection margin involvement. The 5-year local recurrence-free survival, recurrence-free survival, and overall survival were 93.0, 76.2, and 80.5%, respectively. Nine patients experienced local recurrence: lateral pelvic recurrence in six patients (5.0%) and central pelvic recurrence in three (2.5%). A total of 87.4% of sphincter-preserving surgeries were performed for T3 low rectal cancer following SRT-delay. Pathological tumor downstaging, circumferential resection margin involvement, local recurrence, and oncologic outcomes were acceptable; therefore, the SRT-delay regimen may be an option for treating T3 low rectal cancer.