Pulmonary Fibrosis Induced by Cyclophosphamide

OBJECTIVE: To report a case of pulmonary fibrosis resulting from use of cyclophosphamide as chemotherapy to treat a patient with breast cancer. CASE SUMMARY: We describe the case of a 52-year-old woman with breast cancer who developed pulmonary fibrosis after four cycles of chemotherapy that included cyclophosphamide. Pulmonary function tests revealed the presence of a severe ventilatory restriction. The open lung biopsy revealed pulmonary fibrosis with vascular sclerosis and signs of pulmonary hypertension. DISCUSSION: Cyclophosphamide is an alkylating agent that has been associated with interstitial pneumonia and pulmonary fibrosis. The frequency of these unwanted effects is <1%. The clinical picture consists of the progressive appearance of dyspnea and a non-productive cough that progresses to severe pulmonary insufficiency. The risk factors described for these complications have been the use of chemotherapy regimens that include other drugs with known pulmonary toxicities, the cumulative total dose, the addition of radiotherapy, and the use of high doses of cyclophosphamide. CONCLUSIONS: Even though the frequency of pulmonary fibrosis in patients treated with cyclophosphamide-based chemotherapy regimens is low, the presence of dyspnea and an interstitial pattern in a patient makes it necessary to consider that possible drug toxicity. The open lung biopsy is the most accurate diagnostic technique for these cases. The discontinuation of cyclophosphamide and treatment with corticosteroids is usually followed by clinical recovery in approximately 50% of patients and, in some cases, reversal of the lung injury.