Sphincter-preserving surgery for rectal cancer: A population-based study in Taiwan

Background/Aims: Sphincter-preserving surgery (SPS) has been considered a surrogate for surgical quality for rectal cancer. This study aims to assess its rate for rectal cancer between centers and over time in Taiwan. Methodology: Data from 1997 to 2006 on patients undergoing sphincter-preserving surgery (anterior resection or AR) and proctectomy with colostomy (abdominoperineal resection or APR) were extracted from a national health insurance database. Hierarchical logistic regression was used to identify independent factors associated with SPS. Results: Data on 19,919 patients were analyzed. Among them, 12,164 (61%) received AR and 7,755 (39%) underwent APR at total of 115 centers. Multifactorial analysis revealed higher SPS rates with female gender (p<0.001) and patients paying higher insurance premiums (p=0.005). Higher APR rates were seen in those receiving surgery at metropolitan hospitals (p=0.001) and hospitals outside higher volume regions (Taipei City and North, p≦0.005). For hospitals with initial low surgical volumes, significant improvement of SPS rate was found (p<0.001) with increasing volume over the study period. Conclusions: The disparity due to sphincter loss in rectal cancer between hospitals of various regions and levels narrowed in Taiwan. Characteristics of hospital (level, region, volume) and patient (gender, premium level) influenced SPS rate.