THERMORADIOTHERAPY WITH CURATIVE INTENT - BREAST, HEAD AND NECK AND PROSTATE TUMORS

JAMES I. BICHER, M.D., NAZAR Al-BUSSAM, M.D. and RALPH S. WOLFSTEIN, M.D.

Valley Cancer Institute, Los Angeles, California U.S.A.

Objectives: Hyperthermia increases the response of malignant tumors to radiation therapy in experimental animals and clinical treatment. In our experience, first in re-treatment of previously radiated fields that necessitated the use of low dose radiation fractions as adjunct to the heat treatments, and then progressively "de novo" and eventually with curative intent, treatment protocols have been devised and tested that yield positive preliminary data showing superior tumor response rates and less side effects when compared with historical controls at our institute. Based on these results and an increasing world literature we undertook to treat with curative intent superficial heatable tumors of the breast, prostate and head neck regions in patients that had refused conventional cancer therapy.

Methods: The hyperthermia part of the protocol extends the number of heat treatments to correspond to the number of radiation-fractions. The number of hyperthermia treatments therefore varies from 25-50 per course for each treated field. The radiation protocol consists of progressively decreasing daily doses of radiation therapy. Typically the treatment is started at a daily dose of 180 cGy gradually reduced to 100 cGy protracting a typical radiation therapy treatment course from 5000 cGy in five weeks to 5000 cGy given in over eight weeks; or 7000 cGy in seven weeks to 7000 cGy in 14 weeks. According to the ELLIS TDF formula, this results in a 15% or 25% reduction of the effective radiation dose. The total dose is adapted to the clinical situation. To this effect, the use of objective end result parameters is introduced, including MRI, MR Spectroscopy, PET Scanning and Tumor Marker levels. Treatment is continued until these parameters revert to normal. Forty breast patients, 17 head and neck and 15 prostate patients were treated with a follow up period of two to five years. All patients were early stage (less than III ).

Results: Breast patients showed an 82% complete response rate, head and neck patients 88% complete response rate and prostate patients 93% complete response rate. Projected 5 year survival rates were 80% for breast patients, 88% for head and neck, and 87% for prostate patients.

Conclusion: Protracted hyperfractionation of daily thermoradiotherapy

1 Decreases the radiation dose by 15 to 25%;

2 Decreases the side effects of radiation therapy;

3 Allows treating to effect using objective end point parameters (tumor markers, PET scans, MRI, etc.);

4 Accomplishes a high percentage of complete responses in superficial tumors;

5 Accomplishes a high 5-year survival rate in the 80-90% range in early superficial tumors;

6 Is potentially curative in early stage breast, head and neck and prostate cancers.