Analysis of anal sphincter preservation rate according to tumor level and neoadjuvant chemoradiotherapy in rectal cancer patients

The anal sphincter preservation rate (ASPR) according to tumor level and neoadjuvant chemoradiotherpy (CRT) has not been fully evaluated. Therefore, the aim of this study was to evaluate the correlation between the tumor level, neoadjuvant CRT, and the ASPR in rectal cancer patients. We studied 544 patients (tumor level, 0-6 cm) who underwent curative resection for rectal cancer between 1991 and 2005. Patients were divided six into groups according to tumor level over 1-cm intervals, and the ASPR was evaluated in patients with and without neoadjuvant CRT according to tumor level. Sphincter preservation surgery was performed in 191 patients, and 86 patents underwent neoadjuvant CRT. The overall ASPR was 43.0% (37/86) in patients with neoadjuvant CRT and 33.6% (154/458) in patients without neoadjuvant CRT (P∈=∈0.094). In an analysis according to tumor level, the ASPR was 0.0 vs 0.0% in ≫1 cm, 0.0 vs 2.1% in 1∈≫∈2 cm (P∈=∈0.589), 11.8 vs 16.8% in 2∈≫∈3 cm (P∈=∈0.599), 55.6 vs 20.2% in 3∈≫∈4 cm (P∈=∈0.001), 57.7 vs 45.9% in 4∈≫∈5 cm (P∈=∈0.227), and 66.7 vs 69.5% in 5∈≫∈6 cm (P∈=∈0.827). Neoadjuvant CRT did not increase the ASPR in tumor level within ≫6 cm. However, for the tumor level (3∈≫∈4 cm), neoadjuvant CRT significantly increased the ASPR.