NEW "ONCOMARKER" - BOMBESIN - AS AN EVALUATION CRITERION OF RADIATION THERAPY ADEQUACY IN LUNG CANCER

Mitryaeva N.A., Ishkanova M.A., Starikov V.I.

Ukrainian Institute of Medical Radiology, Laboratory of Radiation Endocrinology,82, Pushkinskaya St, Kharkov,61024, Ukraine, fax: (0572)431 125, e-mail: NIP@xniimr.kharkov.ua

Extensive using in clinical practice the quantitative laboratory methods of examination to identify "markers" specific to tumors along with a standard examination is of considerable promise for making an earlier cancer diagnosis. The term "tumor marker" is considered to mean a large group of agents emerged from malignant cells and related with their growth.. Considerable recent attention has been focussed on use of the "tumor markers "in lung cancer diagnostics.

The new "oncomarker ", bombesin, has been used to test the efficacy of radiation therapy in small-cell lung cancer (SCLC). Evaluation of bombesin content was performed in two groups of patients: one consisting of 200 patients with SCLC, aged 45-70, in the course of antitumor treatment and another, of 100 patients ( of the same age group ) suffering from chronic nonspecific lung diseases.

Following irradiation, a 51% reduction in bombesin content, as compared with the content of other "markers", was observed in the patients with more than 50% tumor regression. In the other group of patients with a tumor regression less than 50%, the bombesin content was not different from that before the treatment had started. When compared to such "markers" as CA125, XGH and PSA, the bombesin specificity and sensitivity approximate 98 and 80 per cent, respectively, to the total exclusion of the specificity of the others.

It follows from the above that bombesin is "the marker "of high specificity for SCLC that makes possible monitoring of radiotherapy efficacy in patients with SCLC, for which purpose the "marker" content before and after treatment has to be determined. High content of bombesin detected during irradiation exposure is indicative of unfavorable prognosis that adds extensively to an earlier recognition of the groups with elevated risk for lung cancer.