Treatment of rectal cancer by low anterior resection with coloanal anastomosis.

Objective: Our institution's experience with low anterior resection in combination with coloanal anastomosis (LAR/CAA) for primary rectal cancer was reviewed (1) to determine cancer treatment results, 2) to identify risk factors for pelvic recurrence, and 3) to assess the long-term success of sphincter preservation.
Summary Background Data: Use of sphincter-preserving resection for mid-rectal and selected distal-rectal cancers continues to increase. As surgical techniques and adjuvant therapy evolve, treatment results must be carefully assessed.
Methods: One hundred thirty-four patients treated for primary rectal cancer by LAR/CAA between 1977 and 1990 were studied retrospectively. All pathologic slides were reviewed. Median follow-up was 4 years.
Results: Actuarial 5-year survival for all patients was 73%. Among 36 patients who relapsed, distant metastatic disease had developed at the time of first clinical relapse in most (86%). Pelvic recurrence was detected in 13 patients, an actuarial rate of 11% at 5 years. Mesenteric implants, positive microscopic resection margin, T3 tumor, perineural invasion, blood vessel invasion, and high tumor grade were associated with increased risk for pelvic recurrence. Eleven patients ultimately required permanent colostomy, and in eight instances the cause was pelvic recurrence.
Conclusions: Low anterior resection combined with coloanal anastomosis provides good treatment for mid-rectal cancers and for some distal rectal cancers. Pelvic recurrence is not associated with short distal resection margins but is correlated with the presence of histopathologic markers of aggressive disease in the primary tumor. Long-term preservation of anal sphincter function depends primarily on control of pelvic tumor and can be achieved in more than 90% of patients.