What is unique about nitrosoureas agents in chemotherapy?

Nitrosourea agents are unique in that they have the ability to cross the blood-brain barrier, which allows them to be effective in treating certain types of brain tumors and central nervous system malignancies. This characteristic is critical because many traditional chemotherapy agents do not penetrate this barrier effectively, limiting their effectiveness against cancers located within the brain. This ability enables nitrosoureas to attack malignant cells that are otherwise protected from systemic therapy.

The notion that antitumor activity is limited to advanced stages of cancer is not a specific characteristic associated with nitrosoureas, as they can be employed in various stages depending on the type of cancer. Additionally, while nitrosoureas can have an impact on lymphatic tissues, their action is not exclusively restricted to these areas; they target a broader range of cancers. Furthermore, nitrosoureas are not limited to oral formulations; they can be administered intravenously as well. Hence, the ability to cross the blood-brain barrier is what uniquely distinguishes nitrosoureas from other chemotherapy agents.