A phase II trial testing the thermal dose parameter CEM43 degrees T90 as a predictor of response in soft tissue sarcomas treated with pre-operative thermoradiotherapy.

We prospectively evaluated whether delivering a thermal dose of ≥ 10 cumulative equivalent minutes at 43°C to > 90% of the tumour sites monitored (CEM43°T90) would produce a pathologic complete response (pCR) in ≥ 75% of high-grade soft tissue sarcomas treated pre-operatively with thermoradiotherapy. The impact of thermal dose on local failure (LF), distant metastasis (DM), and toxicity was also assessed. Thirty-five patients ≥ 18 years old with grade 2 or 3 soft tissue sarcomas accessible for invasive thermometry were enrolled on the protocol. All patients received megavoltage external beam radiotherapy (RT) in daily fractions of 1.8-2.0 Gy, five times a week, to a median total dose of 50 Gy and an initial hyperthermia treatment (HT) of 1 h duration utilizing the BSD 2000 with Sigma 60 or MAPA applicators at frequencies of 60-140 MHz. Further HT was given for patients with CEM43°T90 > 0.5 after initial HT (`heatable' patients), twice a week to a maximum of 10 HT or CEM43°T90 > 100. Of the 35 patients ent...