Pulmonary function following adjuvant chemotherapy and radiotherapy for breast cancer and the issue of three-dimensional treatment planning

Background and purpose: The frequency and grade of pulmonary complications following adjuvant radiotherapy for breast cancer are still debated. This s tudy focuses on loss of pulmonary function. Materials and methods: We have measured the reduction of pulmonary function 5 months following radiotherapy in 144 node-positive stage II breast cance r patients by using pulmonary function tests. Results: No deterioration of pulmonary function was detected among the pati ents who were treated with local radiotherapy. On the contrary, there was a mean increase in diffusion capacity by 7% (P = 0.004) following radiothera py, which most likely was explained by the adjuvant chemotherapy administer ed prior to the baseline pulmonary function tests. Patients undergoing loco -regional radiotherapy showed a mean reduction in diffusion capacity by 5% (P < 0.001) and in vital capacity by 3% (P = 0.001). The subset of patients (9%) who were diagnosed with severe pulmonary complications needing cortis one treatment had significantly larger mean paired differences in vital cap acity (-0.446 L, -15% (equivalent to 15 years of normal ageing or the loss of 3/4 of a lung lobe)) compared to the patients who were asymptomatic (-0. 084 L) (P < 0.05). When the effects of potential confounding factors and di fferent radiotherapy techniques were tested on the reduction of pulmonary f unction by stepwise multiple regression analysis, a significant correlation was found only to locoregional radiotherapy including the lower internal m ammary lymph nodes. Conclusions: We conclude that a clinically important reduction of pulmonary function is seen in the subset of patients who are diagnosed with severe p ulmonary complication following loco-regional radiotherapy for breast cance r. The results of this study warrant further studies based on individual lu ng dose volume histograms. (C) 1999 Elsevier Science Ireland Ltd. All right s reserved.