Abdominoperineal resection and low anterior resection: comparison of long-term oncologic outcome in matched patients with lower rectal cancer.

PURPOSE

The current study aimed to compare the oncologic outcome and pattern of metastasis after abdominoperineal resection (APR) and low anterior resection (LAR) treating lower rectal cancer.

METHODS

A total of 804 patients undergoing curative resection (R0) were enrolled prospectively. The APR and LAR groups (n = 402, respectively) were matched for gender, age, and stage, for a retrospectively comparative analysis.

RESULTS

In a multivariate analysis with potential variables, APR itself was not a risk factor for increased local recurrence (LR) or reduced survival (P = 0.243-0.994). Circumferential resection margin (CRM) involvement as an operation-related risk was 1.6-fold more frequent in the APR group and was significantly associated with LR and systemic recurrence (OR, 2.487-4.017; P < 0.01). Circumferential margin positivity (CRM+) was concurrently correlated with advanced stage, larger tumor (long diameter, >4 cm), and longer sagittal midpelvic diameter (>10 cm) in a multivariate analysis (P < 0.001-0.05). The site of metastasis did not differ between the two groups, with the exception of lung metastasis which was more frequent in the APR group (APR vs. LAR: 15.9 vs. 10 %, P = 0.015). In the APR group, CRM+ and the presence of an infiltrating tumor were correlated with disease-free survival (hazard ratio (HR), 1.644 and 1.654, respectively), whereas elevated serum carcinoembryonic antigen and LVI+ were correlated with overall survival (HR, 1.57 and 1.671, respectively), in a multivariate analysis with potential variables (P < 0.05).

CONCLUSIONS

When performed with appropriate skill to achieve R0 resection, APR can be used safely without impairing oncological outcome, although sphincter-preserving surgery should remain the preferred option.