Surgical margins, local recurrence and metastasis in soft tissue sarcomas: 559 surgically-treated patients from the Scandinavian Sarcoma Group Register.

The prognostic importance of surgical margins on local recurrence rates and metastasis-free survival (MFS) was studied in 559 patients with soft tissue sarcoma of the extremities and trunk wall. The patients were all surgically treated, but received no adjuvant treatment. The median follow-up for the survivors was 7.4 (range: 0.1 - 12.5) years. Independent prognostic factors for MFS were analysed by Cox models. The overall 5-year MFS was 0.72 (95% confidence intervals (CI) 0.68 - 0.76). High histopathological malignancy grade (relative risk (RR) 3.0; 95% CI 1.5 - 6.3) and an inadequate surgical margin (RR 2.9; 95% CI 1.8 - 4.6) were independent risk factors for local recurrence. High histopathological malignancy grade and large tumour size (> 7 cm) were the most important risk factors for metastasis. Local recurrence was associated with an increased risk of metastasis (RR 4. 4; 95% CI 2.9-6.8), but an inadequate surgical margin was not a risk factor for metastasis (RR 1.1; 95% CI 0.8-1.7). This study confirms that, as regards metastasis, tumour-related risk factors (malignancy grade and tumour size) are more important risk factors than treatment-related factors. Local recurrence was associated with an increased metastasis rate, whereas inadequate surgical margin was a risk factor for local recurrence but not for metastasis. Hence, the proposed causal association between local recurrence and metastasis is doubtful, and if it exists is a weak association.