Pneumonitis and pulmonary fibrosis associated with breast cancer treatments

To review the available published data regarding the incidence, mechanisms of pathogenesis, clinical presentations and management of pneumonitis caused by anti-cancer treatments (radiotherapy (RT) and systemic agents) that are included in the guidelines of the treatment of breast cancer (BC) and address the issues on the current grading classification of pneumonitis. A literature search was performed between July and October 2013 using PubMed for papers published from January 1989 to October 2013. Any clinical trial, case report, case series, meta-analysis or systematic review that reported on pulmonary toxicity of any BC therapeutic modality was included (only papers published in English). Most of anticancer treatments currently used in the management of BC may induce some degree of pneumonitis that is estimated to have an incidence of 1-3 %. There is an obvious distinction between chemotherapy- and targeted treatment-related lung toxicity. Moreover, the current classification of pneumonitis needs to be modified as there is a clear diversity in grade 2. As pneumonitis is relatively common and reported as side effect of new anticancer agents, physicians need to be aware of the clinical and radiological manifestations of drug- and RT-induced toxicities in patients with BC. A key recommendation is the subdivision of grade 2 cases to two subgroups. We provide an algorithm, along with real life cases as managed in the breast Unit of Royal Marsden Hospital, with the aim to guide physicians in managing all possible eventualities that may come across in clinical practise.