Comparison of radiotherapy side effects on lung volumes and peripherel oxygen saturation in two methods of radiotherapy: two tangential and single anterior supraclavicular field with two tangential and two anterior and posterior opposed supraclavicular fields

Radiotherapy after breast cancer surgery will increase local control of the disease and also increase overall survival. Radiation have some side effects on lung function. In different radiotherapy techniques, these side effects are different. Pulmonary function tests and oxygen saturation are methods for evaluation of these complications. In this study we decide to campare pulmonary complications in two radiotherapy methods. In this clinical trial study fifty one patients with breast cancer in stage II and III according to TNM staging system, which were under modified radical mastectomy in Imam Hosein hospital and refered for adjuvant radiotherapy, randomly divided in two groups. In one group patients were treated with three field technique and in others with four field technique. All patients received total dose of 48-50 Gy. For patients, pulmonary function test and pulse oxymetery were done once before initiation of radiotherapy and then one and three months after radiotherapy. Measurement of FEV1, FVC and show that no significant statistical difference was present between the two groups one month and three months after radiotherapy, also in each of the two groups the amount of FEV1, FVC and one month after radiotherapy had no significant statistical difference in comparison to baseline tests but FEV1 and FVC after three months was decreased and had significant statistical difference respectively (p<0.001, p<0.006). SO2 had no significant defference between the two groups and also in each group after one and three month of radiotherapy. Locoregional radiotherapy of breast and lymph nodes areas causes a decrease in some parameter of pulmonary function tests but no difference was present between three field and four field techniques.