Evaluation of Pulmonary Complications after Tangential Radiotherapy of Breast Cancers through Pulmonary Function Tests and Irradiated Volume of Lung

Pulmonary complications of breast cancer radiotherapy are inevitable. One of methods to assess respiratory alterations is pulmonary function test named spirometry. The aim of the present study was to investigate the effect of radiotherapy on pulmonary function test and to study the related factors. Seventy five patients with stage II and III (TNM staging) of breast cancer undergoing ipsilateral mastectomy and 6 cycles of chemotherapy were included in our study. Spirometry was performed before and 3 months after radiotherapy; the patients were examined at the same time by a specialist for respiratory complications. The measured parameters were forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) which were normalized by age and sex. The Mean age of the patients was 45.6±7.92 years. The mean length and width of tangential field was 18.2 ±1.8 and 6.7±1.37 cm, respectively. The mean central lung distance was 2±1.07 cm corresponding to 22% of the irradiated volume of lung at maximum. The mean FEV1 percent before and after radiotherapy were respectively 74.9±15.99 and 78.86±12.55, respectively (P=0.09). Moreover, the mean FVC percent before and after the radiotherapy were 72.17±14.26 and 74.60±11.36, respectively (P=0.07). Three months seem not to be enough for showing pulmonary changes due to 60Co radiotherapy. Moreover, the role of minimizing central lung distance through planning may be crucial to reduce the possibility of radiation pneumonitis.