PROGNOSTIC FACTORS FOR ACUTE AND LATE SKIN REACTIONS IN RADIOTHERAPY PATIENTS

Purpose: Patients treated with identical radiotherapy schedules show a substantial variation in the degree of acute and late normal tissue r eactions. To identify any possible contributing factors to this phenom enon, we have analyzed the treatments of 402 breast cancer patients. M ethods and Materials: The patients received adjuvant postoperative rad iotherapy between 1972 and 1985 and have been followed up since then. Multivariate analyses were performed with peak reflectance erythema an d peak acute reaction score as endpoints for the acute reactions, and with progression rate of telangiectasia as well as telangiectasia scor e as endpoints for the late reactions. Twenty patient- and treatment-r elated factors were tested such as age, menopausal status, hemoglobin level, serum calcium, smoking habits, hypothyroidism, diabetes, hypert ension, blood pressure, cardiovascular and autoimmune disease, the inf luence of hormone therapy and chemotherapy, pretreatment reflectance v alue, acute skin reactions, radiation quality, individual dose, bilate ral fields, and the total effect (TE) for the dose schedule applied. R esults: The TE was a strong prognostic factor for all endpoints. In ad dition to TE, blood pressure was prognostic for the peak erythema meas ured by reflectance spectrophotometry, and the pretreatment reflectanc e value was prognostic for the acute score. The only independent progn ostic factors found for the progression of skin telangiectasia and tel angiectasia score except for TE were the individual dose and the acute skin reactions. Conclusions: These factors explained at most about 30 % of the variance describing the total patient-to-patient variability for each endpoint. The remaining variability is still unexplained but may be related to individual differences in cellular radiosensitivity, partly determined by genetic variations and partly by unknown epigene tic factors. Copyright (C) 1996 Elsevier Science Inc.