Clinical application of low dose-rate brachytherapy combined with simultaneous mild temperature hyperthermia.

Background: Recent biological research has shown that mild temperature hyperthermia (MTH) around 41°C simultaneously combined with low dose-rate irradiation (LDRI) is an effective treatment modality for cancer. The aim of the study was to assess the clinical usefulness of a combination of MTH and simultaneous low dose-rate brachytherapy. Materials and Methods: Seven superficial and 8 deep-seated tumors were included in this protocol. Two tumors had no previous treatment and the remainder were recurrent tumors which had arisen from previously treated sites. The average major diameters of superficial and deep tumors were 8.6 and 7.0 cm, respectively. The average values for Tmin in superficial and deep tumors were 41.5 and 40.7°C, respectively. Brachytherapy was delivered by 137 Cs and/or 192 Ir LDRI sources. Results: For superficial tumors, six of the seven tumors responded to the treatment (4 achieved CR, 2 PR, 1 NC) and four tumors did not recur within the follow-up period of 5-15 months. All of the deep tumors responded and 5 achieved CR, 3 PR. Four tumors recurred 4-17 months after the treatment and the remainder showed no local recurrence within the follow-up period of 4-31 months. Conclusion: MTH simultaneously combined with LDRI was an effective method for treating progressive and bulky tumors with a previous treatment history.