What requires monitoring due to the risk of pulmonary fibrosis when using Carmustine (BCNU)?

Carmustine (BCNU) is an alkylating agent that is used in cancer treatment, particularly for brain tumors and certain types of lymphoma. One of the notable risks associated with its use is the development of pulmonary fibrosis, which is a serious lung condition that leads to scarring and stiffness in the lungs, impacting respiratory function.

Monitoring chest X-rays is critical when a patient is undergoing treatment with Carmustine because these imaging studies can help detect early signs of pulmonary toxicity or fibrosis. Regular chest X-rays provide valuable information about changes in lung structures, indicating whether the patient is developing complications associated with the drug.

While other options such as kidney function tests or liver function tests are important in monitoring the overall health and managing side effects related to other potential toxicities from cancer treatments, they do not specifically address the risk of pulmonary fibrosis associated with Carmustine. Neurological assessments, while relevant for monitoring central nervous system effects given Carmustine's use in treating brain tumors, do not target the pulmonary complications and are, therefore, less relevant in this context.

Thus, monitoring chest X-rays is essential for timely identification and management of pulmonary complications that may arise during treatment with Carmustine.