Long-term recurrence of soft tissue sarcomas: prognostic factors and implications for prolonged follow-up.

Background: To the authors' knowledge, the incidence of late recurrence (> 5 years after initial management) is unknown and no prognostic factors for late events have been characterized in patients with soft tissue sarcomas.

Methods: Follow-up data from patients with localized soft tissue sarcoma who were included in the French Sarcoma Group database from January 1990 to June 2005 were reviewed. The outcomes of interest were the cumulative probabilities of late (> 5 years) local and metastatic disease recurrence with death as a competing event. Estimations and 95% confidence intervals (95% CIs) were computed with the cumulative incidence function.

Results: A total of 719 patients who were alive and event free > 5 years after their initial diagnosis were included in the current study. Sixty-seven patients (9.3%) developed a late local recurrence and 42 patients (5.8%) developed a late metastatic recurrence, respectively. On multivariate analysis, internal trunk location (hazard ratio [HR], 3.9; 95% CI, 2.2-6.7 [P < .001]) and tumor size > 100 mm (HR, 2.1; 95% CI, 1.1-4 [P = .035]) were the 2 factors found to be independently associated with an increased risk of late local recurrence. Grade > 1 (graded according to the French Federation of Cancer Centers Sarcoma Group) (HR, 4.7; 95% CI 1.1-21 [P = .04]) was the sole factor found to be independently associated with an increased risk of late metastatic recurrence.

Conclusions: Late recurrence of soft tissue sarcoma is relatively uncommon. However, the results of the current study emphasize the critical role of long-term follow-up to detect late local disease recurrence in patients with retroperitoneal or very large soft tissue sarcomas, and late metastatic recurrence in patients with high-grade disease. Conversely, the prolonged follow-up of patients with grade 1 disease is not needed.