What is the difference between neoadjuvant and adjuvant therapy?

According to the NCI Dictionary of Cancer Terms, the two terms describe when treatment is given relative to a person's main cancer treatment. The NCI defines neoadjuvant therapy as "treatment given as a first step to shrink a tumor before the main treatment, which is usually surgery, is given." The NCI defines adjuvant therapy as "additional cancer treatment given after the primary treatment to lower the risk that the cancer will come back." So the core difference is timing and goal: neoadjuvant comes before the main treatment (often to shrink a tumor), while adjuvant comes after it (to reduce the chance the cancer returns). The NCI notes that both can involve chemotherapy, radiation therapy, or hormone therapy; adjuvant therapy may also include targeted therapy or biological therapy. This is general information, not personal medical advice.

Last updated: 2026-07-12

← Back to all questions