Long-term results of intersphincteric resection for low rectal cancer.

INTRODUCTION: In the treatment of very low rectal cancer, a distal resection margin of more than 1 cm can be obtained by partial internal sphincteric resection, allowing a sphincter preserving surgery. Thus, intersphincteric resection (ISR) has been proposed as an alternative to abdominoperineal resection for selected low rectal cancer.

OBJECTIVE: The aim of our study was to assess the morbidity, mortality, and the long-term oncologic and functional results of ISR.

METHODS: Charts of patients who had ISR between 1992 and 2004 were reviewed. Cancer-related survival and locoregional recurrence rates were calculated using the Kaplan-Meier method. Functional outcome was assessed by using a standardized gastrointestinal functional questionnaire. Incontinence was assessed by the continence score of Wexner.

RESULTS: Ninety patients (59 males, 31 females) with a tumor at a median distance of 35 mm (range, 22-52) from the anal verge had an ISR. Thirty-seven patients (41%) had preoperative radiotherapy. Histologically complete remission after neoadjuvant radiotherapy (ypT0) was observed in 7 patients (8%), 12 patients (13%) were pT1, 35 patients (39%) pT2, 32 patients (36%) pT3, and 4 patients (4%) pT4. Five patients (5.5%) had synchronous liver metastases. R0 resection was obtained in 85 patients (94.4%). The median distal resection margin on the fixed specimen was 12 mm (range, 5-35) and was positive in 1 case. The circumferential margin was positive (< or =1 mm) in 4 patients (4.4%). There was no mortality. Complication rate was 18.8%: anastomotic leakage occurred in 8 patients (8.8%) and 1 patient had an anovaginal fistula. Five patients (5.6%) underwent secondary abdominoperineal resection: 1 for positive distal margin, 1 for colonic J-pouch necrosis, and 3 for local recurrence. ONCOLOGIC RESULTS: After a median follow-up of 56.2 months (range, 13.3-168.4), local, distant, and combined recurrence occurred in 6 (6.6%), 8 (8.8%), and 2 patients, respectively. Thirteen patients (14.4%) died of cancer recurrence. Five-year overall and disease-free survival was 82% (80-97) and 75% (64-86), respectively. In univariate analysis, overall survival was significantly influenced by pTNM stage and T stage (pT 1-2 vs. 3-4: P = 0.008 and stage I-II vs. III-IV: P = 0.03). In multivariate analysis, we did not find any impact on local recurrence-free survival for the investigated prognostic variables.

FUNCTIONAL RESULTS: For a total of 83 patients the mean stool frequency was 2.3 +/- 1.3 per 24 hours. Forty-one percent of patients had stool fragmentation, one-third nocturnal defecation, 19% fecal urgency, and 36% followed low fiber diet. Thirty-four patients (41%) were fully continent, 29 patients (35%) had minor continence problems, and 20 patients (24%) were incontinent. After adjustment for age, gender, tumor level, and pTNM stage, preoperative radiotherapy was the only factor associated with a risk of fecal incontinence [OR (IC 95%) = 3.1 (1.0-9.0), P = 0.04].

CONCLUSION: In selected patients, ISR is a safe operation with good oncologic results. It achieves good functional results in 76% of patients. Functional results are significantly altered by preoperative radiotherapy.