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 x791p4ecimen may be used for selection of patients for adjuvant radiotherapy and/or chemotherapy.
In order to assess the effect of the no-touch isolation technique, in the treatment of large bowel cancers, on the site of first recurrence and disease-free and overall survival, 236 patients were prospectively and randomly assigned to either the no-touch isolation technique (117 patients) or to a conventional resection technique (119 patients). No patient with distant metastases or unresectable disease entered the study. The two treatment groups were comparable with regard to patient characteristics. Pre- and postoperative complications (including mortality within 30 days) were similar in both groups. After a complete follow-up of 5 years, a tendency for reduction in the number of, and time to, occurrences of liver metastases was seen in the no-touch isolation group (P = 0.14). This effect was most obvious in the sigmoid colon with angio-invasive growth. Overall (P = 0.42) and corrected (P = 0.25) survival did not differ significantly among the treatment groups although in every analysis the survival data of the no-touch isolation group were superior. The data do suggest a limited benefit of the no-touch isolation technique. This observation is important since the morbidity and mortality of surgery were equal in both groups.
Casecohort and nested casecontrol sampling metho-have recently been intro-xed as a means of reducing cost in large cohort studies. The asymptotic distribution theory results for relative rate estimation based on Cox type partial or pseudolikelihoods for casecohozt and nested case-control studies have been accounted for. However, many researchers use (stratified) frequency table methods for a first or primary summarization of the most important evidence on exposuredisease or dose-response relationships, i.e. the classical Mantel-Haenszel analyses, trend tes% and tests for heterogeneity of relative rates. These can be followed by exponential failure time regression methods on groupad or individual data to model relationships between several factors and response. In this paper we present the adaptations needed to use these methods with casecohort designs, illustrating their use with data from a recent casecohort study on the relationship between diet, life-style and cancer. We assume a v a y general setup allowing piecewise constant failure rates. possible recumnt events per individual, independent censoring and left truncation.
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