Local recurrence of rectal cancer in patients not receiving neoadjuvant therapy - the importance of resection margins.

OBJECTIVES Local recurrence of rectal cancer reduces quality of life and survival. A multi-factorial linear logistic model was used to analyse risk factors for local recurrence in rectal cancer in patients not receiving preoperative chemo-radiation. METHODS A case-control study of patients with rectal cancer having surgery with curative intent, between 1996 and 2008. Eighteen putative risk factors for local recurrence were subjected to uni-variate analysis. Significant factors were selected for multi-factorial analysis. RESULTS Twenty-one patients with local recurrence (cases) and 78 controls were selected. Uni-variate analysis showed significant associations with recurrence for nodal stage (N) (p=0.027), metastasis (M) (p=0.009), adjuvant chemotherapy (p=0.039), positive resection margin (R) (p=0.018) and American Joint Committee for Cancer (AJCC) tumours above stage II (p=0.043). Significant uni-variate odds ratios (OR) were obtained for the same factors. Two linear logistic models were fitted as (1) N, M, R1 status and adjuvant chemotherapy and (2) AJCC stage, R1 status and adjuvant chemotherapy. From both models, the only factor significantly associated (p ≤ 0.01) with local recurrence was found to be a positive resection margin (OR 4.81 and 5.51 respectively). CONCLUSIONS A positive resection margin is the single factor affecting local recurrence of rectal cancer in patients not receiving neo-adjuvant therapy.