High-dose rate brachytherapy alone in postoperative soft tissue sarcomas with close or positive margins

In the management of soft tissue sarcomas, perioperative radiation therapy has been used to reduce the risk of local recurrence after resection. However, a significance of postoperative high-dose rate brachytherapy (HDRBT) remains to be studied. Retrospective analysis was performed to elucidate the role of postoperative HDRBT.

Twenty-five patients with 26 soft tissue sarcoma lesions underwent postoperative HDRBT using (192)Ir remote afterloader without external beam radiation therapy. Ninety-two percent of the lesions were Grade 2 or 3 malignancies, and 50% were resected with positive surgical margins. The remaining 50% had very close margins. Fourteen lesions were treated for local recurrences after previous resections. Applicators of HDRBT were placed during the operation to include only the tumor bed excluding surgical scars. Applied dose was mainly 36Gy/6 fractions/3 d b.i.d.

Five-year local recurrence-free survival was 78.2% in all the 26 lesions. Recurrences were not seen within the treated volume of HDRBT. Two groups were defined according to the marginal status and number of previous operations. Group 1 was the lesions with a positive margin and foregoing resections. The remaining lesions were classified as Group 2. Five-year local recurrence-free survival was 43.8% and 93.3% in Group 1 and Group 2, respectively with a statistically significant difference (p=0.004).

Postoperative HDRBT was effective in controlling local lesions; but in Group 1 lesions, addition of a wide field external beam radiation therapy seems to be necessary to improve the local control rate.