Why is bleomycin sulfate stopped once a cumulative dose of 220 units/m2 is reached?

Bleomycin sulfate is a chemotherapeutic agent known to cause specific adverse effects, notably pulmonary toxicity. The risk of developing pulmonary complications, such as pneumonitis and pulmonary fibrosis, increases significantly when the cumulative dose reaches a threshold of approximately 220 units/m2. This accumulation of the drug is associated with damage to the lung parenchyma, which can lead to long-term respiratory issues and decreased pulmonary function.

Monitoring and limiting the total dose to this level helps to mitigate the risk of these serious pulmonary complications, which are a primary concern for patients treated with bleomycin. This is particularly relevant as the lung toxicity seen with bleomycin can be delayed and does not always correlate directly with observable symptoms at lower cumulative doses. Understanding this risk is crucial for healthcare providers to manage treatment safely and effectively.