Abstract

BACKGROUND AND PURPOSE:

The frequency and grade of pulmonary complications following adjuvant radiotherapy for breast cancer are still debated. This study 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 cancer patients by using pulmonary function tests.

RESULTS:

No deterioration of pulmonary function was detected among the patients who were treated with local radiotherapy. On the contrary, there was a mean increase in diffusion capacity by 7% (P = 0.004) following radiotherapy, which most likely was explained by the adjuvant chemotherapy administered 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 cortisone treatment had significantly larger mean paired differences in vital capacity (-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 different radiotherapy techniques were tested on the reduction of pulmonary function by stepwise multiple regression analysis, a significant correlation was found only to locoregional radiotherapy including the lower internal mammary 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 pulmonary complication following loco-regional radiotherapy for breast cancer. The results of this study warrant further studies based on individual lung dose volume histograms.