Can 8-oxo-dG be used as a predictor for individual radiosensitivity?

Purpose: To develop predictive tests for individual radiosensitivity of tum or patients. Methods and Materials: Acute skin reactions were clinically scored among 40 women after 46 Gy, given with 2 Gy fractions to breast and regional lymph nodes, adjuvant after surgery. The acute skin reactions were compared to th e excretion of 7,8-dihydro-8-oxo-2'-deoxyguanosine (8-oxo-dG) in urine, det ermined by high-performance liquid chromatography (HPLC) with electrochemic al detector. Specimens of urine were collected before and during postoperat ive radiation treatment at given intervals, We compared a group of 9 patien ts with the most pronounced skin reactions with another group of 8 patients with almost no skin reactions at 46 Gy, Results: The level of 8-oxo-dG excreted in urine during 8 h was measured, A fter normalizing the excretion to irradiated volumes, dose per volume and e xcretion before irradiation, the 8-oxo-dG level in urine was significantly (p < 0.001) lower for the patients with pronounced skin reactions as compar ed to patients with minor skin reactions, at an accumulated dose of 12 Gy, In addition, the background level of 8-oxo-dG excreted before treatment sta rted, was significantly (p = 0.043) lower for patients with minor skin reac tions as compared to patients with pronounced skin reactions. The backgroun d level of 8-oxo-dG was corrected for body weight and normalized to BMI, Conclusion: We suggest that the excretion of 8-oxo-dG into urine of breast cancer patients is a possible marker for acute radiosensitivity, (C) 2001 E lsevier Science Inc.