Antitumor

Antitumor is a term used to describe substances, therapies, or processes that counteract tumor growth or promote tumor regression. It can refer to direct effects on cancer cells, immune-mediated anticancer activity, or modulation of the tumor microenvironment.

Direct antitumor actions include damaging DNA, inhibiting DNA replication, triggering apoptosis or senescence, and disrupting mitosis. These effects are the principal mechanism of many conventional chemotherapeutic agents such as alkylating agents (for example cyclophosphamide), antimetabolites (such as 5-fluorouracil), and topoisomerase inhibitors. Targeted therapies and molecularly guided approaches interrupt specific oncogenic pathways, improving selectivity for cancer cells.

Immune-mediated antitumor activity arises when the immune system recognizes and destroys cancer cells. This is achieved through immunotherapies such as immune checkpoint inhibitors, adoptive cell therapies, cancer vaccines, and other strategies that boost antitumor immune responses. Anti-angiogenic approaches reduce tumor blood vessel formation, indirectly limiting tumor growth and survival.

Clinical use emphasizes achieving tumor control or regression while managing toxicity. Side effects vary by modality and can include myelosuppression, nausea, neuropathy, and organ-specific toxicities. Resistance and tumor heterogeneity remain significant challenges, motivating ongoing research into combination regimens, precision oncology, and methods to overcome immune evasion.

Examples of antitumor strategies range from widely used chemotherapies to newer immunotherapies and targeted agents, illustrating the breadth of approaches aimed at suppressing tumor growth and improving patient outcomes.