[Adjuvant radiation therapy for soft tissue sarcoma of the extremities: analysis of local control according to volume and dose].

PURPOSE

To evaluate retrospectively the anatomical definition of target volumes in the treatment of soft tissue sarcomas of the limbs and to study the radiation dose in the local control and toxicity.

METHODS AND PATIENTS

Seventy-seven patients were consecutively treated for primary soft tissue sarcoma of the extremity with limb sparing surgery and external beam radiotherapy (EBRT) in the same institution. The median follow up was 56 months (17-89 months).

RESULTS

Fifty-two patients (67%) had clear microscopic surgical margin (R0 resection), 23 (30%) had histologically positive microscopic margin (R1 resection), 2 had a macroscopic residual disease (R2 resection). An anatomical definition of target volumes has been realised. The mean dose was 50 Gy in 25 or 28 fractions; 23 patients received a boost restricted to the tumor bed: 13 with EBRT, 10 with brachytherapy (BRT). Thirty-four patients had an adjuvant chemotherapy. The overall 5 year local relapse rate was 10%. Seven local relapses were described, five of the high-grade tumours, and five in patients with positive margin. In univariate analysis, quality of surgery shows a significant effect for local control. By using LENT-SOMA scale for late toxicity, a significant difference was found for neurological complications for patients receiving a boost.

CONCLUSIONS

The results of the series validate the concept of anatomical definition of the initial target volume. A boost should be realised for positive margin tumors and may be for high-grade tumors. Neurological toxicity must be considered for the evaluation of the prescribed dose.