Interactions of Radiotherapy With Hormonotherapy

Abstract

The various forms of adjuvant therapy in breast cancer including postoperative irradiation and chemotherapy or hormonal therapy decrease the mortality rate among the affected population. Adjuvant radiotherapy is a standard form of treatment after breast-conserving surgery and certain mastectomized patients. Periodically, some patients can suffer from long-term toxicity such as radiation pneumonitis or radiation fibrosis of the lung. In very rare situations after breast radiotherapy, bilateral lymphocytic alveolitis of the lung (BAL) can occur. BAL is an accepted allergic reaction of the lung and this form has different etiologic and pathologic factors apart from radiation pneumonitis and radiation fibrosis. BAL is a bilateral reaction of the lung but it occurs after unilateral thoracic apex irradiation resulting from radiotherapy in breast carcinoma patients [1]. In one study, patients with pneumonitis at the time of BAL had significantly higher (p<0.05) alveolar CD4 subset cells (24.8±10.2%) than asymptomatic patients (15.2±8.9%). Maximal reductions in total lung capacity (p<0.01) and residual volume (p<0.05) occurred 60 days after irradiation. The early lymphocytic alveolitis which can occur in breast cancer patients after unilateral irradiation is always bilateral and does not predict subsequent development of radiologic evidence of pneumonitis [1, 2]. This situation is different than radiation pneumonitis and fibrosis. True radiation pneumonitis and fibrosis resulting from radiotherapy in breast carcinoma patients is of different incidence. The incidence changes because of reasons such as usage of particular drugs and radiation therapy techniques, as well as other causes. Nonetheless, radiotherapy of the breast can cause long-term effects such as radiation pneumonitis and fibrosis on lung, or skin reactions such as dermatitis or fibrosis. The incidence of lung injury resulting from radiation in breast cancer patients varies between 4.5% and 63% [3]. Some radiation pneumonitis and fibrosis are silent. However, when imaging modalities are used, side effects can be seen. Because the irradiated lung volume is very small, most of these side effects do not change patient activities of daily living or lung capabilities.