Prognostic significance of radial margins of clearance in rectal cancer

A retrospective review of 325 patients was undertaken to analyse whether involvement of the radial resection margin (RRM) could predict locally recurrent disease or distant metastases in patients who had curative surgery for rectal or rectosigmoid cancer. Information on the RRM was available in 253 patients. The RRM was involved in 31 (12 per cent). Nine of these 31 patients developed local recurrence (29 per cent), while only 17 local recurrences were diagnosed in 217 patients (8 per cent) without involvement of the RRM (P<0.01). At 2 years the overall local recurrence rate was 10 per cent. Distant metastases were diagnosed in 46 patients (18 per cent) and RRM involvement was identified as a prognostic factor depending on lymph node involvement (N stage) (P=0.02). Local recurrence and some distant metastases result from microscopically incomplete resection. Assessment of the radial depth of tumour invasion by careful histological examination of the specimen may be used for selection of patients for adjuvant radiotherapy and/or chemotherapy.