Pneumothorax during Pemetrexed Treatment in a Patient with Non-Small Cell Lung Cancer: A Case Report and Literature Review

Pemetrexed is a multitargeted antifolate that has demonstrated antitumor activity in non-small cell lung cancer. A 70-year-old male presented with a stage IV non-small cell lung cancer. The patient was treated with pemetrexed as third-line chemotherapy. However, a pneumothorax occurred 16 days after the administration of the second cycle of pemetrexed. The pneumothorax was slight and the patient was observed without undergoing any additional treatment. Twenty-four days after its initial occurrence, the pneumothorax had improved. This is the first case of pneumothorax that has been observed during pemetrexed treatment. Pneumothorax during chemotherapy is rare; however, it is a life-threatening complication and should not be overlooked.