Assessment of external breathing after gamma teletherapy for breast cancer

In 20 patients undergoing surgery for breast cancer and postoperative radiotherapy on a ''Rocus'' gamma teletherapy unit with 3 direct and 2 tangential fields, at total focal doses in the range of 4500-5000 rad delivered over 7 - 9 weeks, observations were made of exterior breathing kinetics. Between surgery and radiotherapy, and at time intervals of 1 month, 6 months, and 1 year after cessation of radiotherapy, static (vital capacity) and dynamic (forced expiratory volume, forced inspiratory volume) lung volumes were tested. The results of this follow-up indicated no changes in static pulmonary volumes. On the other hand, dynamic lung volumes were found to have undergone considerable change at the first examination following surgery; these changes persisted in some patients up to one year after radiotherapy was discontinued. With some reserve owing to the techniques' limitations, it seems that postoperative radiotherapy was responsible for no substantial contribution to pathological disturbance of static and dynamic pulmonary volumes over the various observation periods. (author)