Interstitial brachytherapy in soft tissue sarcomas. The Tata Memorial Hospital experience

Soft tissue sarcomas are relatively rare tumors with an aggressive natural history associated with a high propensity for local recurrence following conservative surgery. It accounts for 1.8% of all cancers seen at the Tata Memorial Hospital, Mumbai. Organ preserving surgery and tumor bed brachytherapy have revolutionized the management of soft tissue sarcomas.

One hundred and seventy-seven patients with histologically proven non-metastatic cases of soft tissue sarcomas in the age group of 16 to 79 years (median 41 years) were treated at the Tata Memorial Hospital between January 1983 and December 1992. One hundred and fifty-one patients who had completed a minimum of 24 months of treatment were studied. There were 100 males (66%) and 51 females (33%). The majority had recurrent lesions (70.3%). Extremities were involved in 75% of patients. Spindle cell sarcoma was the major histologic variant (30%). The patients underwent function preserving surgery and temporary afterloading Ir-192 tumor bed brachytherapy with or without external radiotherapy.

In patients receiving brachytherapy only, 25 out of 33 (75%) were locally controlled after a median follow-up of 30 months. After successful salvage of local failures the overall local control improved to 82%. Similarly in the patients who received both interstitial brachytherapy and external irradiation, the local control rate after a median follow-up of 40 months was 71% which improved to 86% after successful salvage. The overall treatment related complication rate was less than 1%. The only marginally significant prognostic factor for local control was tumor grade (p = 0.06).

The sequential combination of limited surgery and tumor bed brachytherapy with or without external radiotherapy has been established as an effective alternative to more ablative procedures like amputation. Histologic grade has proven to be a significant factor determining local control.