Clinical usefulness of determining the rate of thermal clearance within heated tumors.

Between June 1987 and June 1988, 28 patients (28 tumors) with liver, retroperitoneal, intrapelvic, or superficial tumors were treated with hyperthermia combined with radiotherapy and/or chemotherapy. Hyperthermia was administered once or twice a week for 30-60 min per session, up to a total of 2-11 sessions, with an 8-MHz RF capacitive heating device. Blood flow in the tumors was evaluated from the rate of thermal clearance (TCR) using the bio-heat transfer equation. The TCR was measured in the middle of the first heating session and at the end of the last heating session by turning off the output power of the heating device. For 9 patients, contrast-enhanced CT scans were taken and CT numbers at the centers of tumors were measured before and after the entire course of hyperthermia. Changes in TCR were closely related to average tumor center temperature, changes in CT number, and tumor response. When smaller and more superficial tumors were treated by hyperthermia combined with radiotherapy and/or chemotherapy that consisted of many heating sessions and during which a high average tumor center temperature was achieved, a better tumor response was obtained. The better the tumor response, the higher the local control rate became. The cause-specific survival rate of patients who achieved good tumor responses was higher than that of patients who showed poor tumor responses. Changes in TCR and CT number in heated tumors were useful and important indicators of tumor response to hyperthermia.

Micronuclei assay--a predictive variable for tumor response to treatment.

Our preliminary data indicate that the formation of micronuclei (MN) in treated tumor cells is a predictive variable for tumor response to treatment. In a pilot study involving four patients who received both radiation therapy and hyperthermia, fine needle aspirate (FNA) samples were taken and analyzed before therapy, and after each 1000 centigray (cGy) up to 3000 cGy. The results indicate a correlation between increasing formation of micronuclei and decreasing tumor volume. All of the patients in this Study have had their tumors under control for at least one year. Our preliminary data demonstrated that a high level of micronuclei in tumor cells correlates with favorable response of the tumor to treatment with radiation and heat. The assay is easy to perform and FNA biopsy could be done in the clinic with minimal discomfort to the patient.