Background: Knowledge of prognostic factors following resection for rectal cancer may be used for selection of patients for adjuvant therapy. In this study we examine the prognostic impact of the circumferential resction margin (CRM) on local recurrence (LR), distant metastases and survival rates.
Methods: A population based national rectal cancer registry included all 3319 new patients from November 1993 to August 1997. 686 patients underwent a Total Mesorectal Excision with known CRM. The shortest radial resection margin, i.e. the CRM, was measured in fixed specimens. None of the patients had adjuvant radiotherapy.
Results: After a median follow up of 29 months (range 14-60), the overall LR rate was 7%(46/686); 22% in CRM positive patients (CRM=0-1mm) and 5% in CRM negative patients (CRM>1mm) (HR 4.7;95%CI 2.5-8.7). 40% of the CRM positive patients had distant metastases, compared to 12% of the CRM negative patients (HR 4.2;95%CI 2.3-6.6). Overall survival was 63% in CRM positive and 87% in CRM negative patients (HR 3.0;95%CI 1.9-4.7). A decrease of CRM was followed by an exponential increase in the rates of LR, metastases and mortality.
Conclusion: CRM has a significant and major prognostic impact on LR, distant metastases and on survival rates. Information on CRM is important for the selection of patients for selective postoperative adjuvant therapy.