Long-term Oncologic Outcomes of Laparoscopic Anterior Resections for Cancer with Natural Orifice Versus Conventional Specimen Extraction: A Case-Control Study

BACKGROUND: Although the short-term advantages of natural orifice specimen extraction are widely recognized, controversy exists concerning oncologic safety after laparoscopic surgery for colorectal cancer. OBJECTIVE: This study aimed to investigate the impact of natural orifice specimen extraction on local recurrence and long-term survival of patients undergoing colorectal cancer surgery. DESIGN: This is a propensity score-matched comparative study. SETTING: This study presents a single-center experience. PATIENTS: We retrospectively analyzed the records of patients who underwent curative laparoscopic anterior resection for American Joint Committee on Cancer stage I to III sigmoid or upper rectal cancer in 2011 to 2014, based on prospectively collected data. INTERVENTIONS: Oncologic outcomes were compared between patients undergoing natural orifice or conventional specimen extraction by minilaparotomy. Patients were matched 1:1 according to propensity scores calculated by logistic regression analysis with the following covariates: American Joint Committee on Cancer stage, tumor diameter, age, sex, BMI, and T stage. Cox proportional hazards regression analysis was performed to determine the impact on oncologic outcome. MAIN OUTCOME MEASURES: The primary outcomes measured were local recurrence and disease-free survival rates at 5 years. RESULTS: Of 392 eligible patients, 188 were matched (94 undergoing natural orifice specimen extraction and 94 undergoing conventional extraction by minilaparotomy). Median follow-up was 50.3 months. The cumulative local recurrence risk at 5 years was 2.3% and 3.5% (p= 0.632), whereas 5-year disease-free survival for all tumor stages combined was 87.3% and 82.0% (p= 0.383) in laparoscopic anterior resection with natural orifice specimen extraction and conventional extraction groups. T3 and T4 stages were the only variables independently associated with disease-free survival. LIMITATIONS: This study was limited because it focused on a single center, was a retrospective analysis, contained no long-term anorectal function testing, and had a small sample size. CONCLUSION: Long-term oncologic outcomes of patients undergoing laparoscopic anterior resection with natural orifice specimen extraction for sigmoid and upper rectal cancer do not differ from those undergoing conventional extraction. Thus, natural orifice specimen extraction could be a viable alternative to reduce abdominal wall insult in laparoscopic colorectal operations for malignancy in selected patients.