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Title: Cumulative minutes with T[sub 90] greater than temp[sub index] is predictive of response of superficial malignancies to hyperthermia and radiation

Journal Article · · International Journal of Radiation Oncology, Biology and Physics; (United States)

The purpose of this work is to better define thermal parameters related to tumor response in superficial malignancies treated with combined hyperthermia and radiation therapy. Patients were randomized to receive one or two hyperthermia treatments per week with hyperthermia given during each week of irradiation. Hyperthermia was given for 60 min with treatments begun within 1 hr following irradiation. Power was increased to patient tolerance or normal tissue temperature of 43.0[degrees]C. Irradiation was generally given 5 times per week with doses prescribed to normal tissue tolerance (generally 24--70 Gy at 1.8--2.5 Gy per fraction). Multipoint thermometry was used with temperatures obtained every 5 min. One hundred eleven individual treatment fields containing 1 or more tumor nodules were completely evaluable. The complete and overall response rates were 46% and 80%, respectively. Forty-one percent of all treatment fields (51% of responding lesions) remained controlled at 2 years. Multivariate analysis revealed that the cumulative minutes that the temperature achieved by 90% of the measured tumor sites (T[sub 90]) was [ge] 40.0[degrees]C, tumor histology, tumor volume, and radiation dose were significantly associated with complete tumor response. The complete response rate was not significantly affected by the number of hyperthermia treatments given per week. The incidence of clinically significant complications was low. These results support the usefulness of the cumulative minute system in describing time-temperature relationships. The significance of thermal variables with regard to tumor response strongly supports the contention that hyperthermia can be a useful adjunct to irradiation for the local control of cancer. 18 refs., 2 figs., 5 tabs.

OSTI ID:
6523414
Journal Information:
International Journal of Radiation Oncology, Biology and Physics; (United States), Vol. 25:5; ISSN 0360-3016
Country of Publication:
United States
Language:
English