neoadjuvantadjuvant

Neoadjuvant therapy and adjuvant therapy refer to the timing of systemic cancer treatment relative to the main local treatment, usually surgery. Neoadjuvant therapy is given before the primary treatment to shrink tumors, improve operability, and address micrometastatic disease. Adjuvant therapy is given after the primary treatment to reduce the risk of recurrence by eradicating residual cancer cells.

Therapies used in either setting include chemotherapy, endocrine therapy for hormone receptor–positive tumors, targeted agents (such as HER2-directed therapy), immunotherapy, and radiation in some contexts. The choice depends on tumor type, stage, biology, patient factors, and treatment goals. Neoadjuvant approaches can provide a direct assessment of tumor responsiveness and may yield a pathological complete response, while adjuvant therapy aims to prolong systemic control after local treatment. Decision-making commonly relies on multidisciplinary evaluation and approved clinical guidelines.

Common examples include breast cancer, where neoadjuvant chemotherapy or endocrine therapy may be given before surgery, with adjuvant chemotherapy, endocrine therapy, or targeted therapy after surgery. In rectal cancer, neoadjuvant chemoradiation is used to shrink tumors before resection; in colorectal cancer, adjuvant chemotherapy after colectomy is a standard option for certain stages. Other cancers may use neoadjuvant or adjuvant strategies based on tumor biology and evidence.

Potential advantages of neoadjuvant therapy include tumor downstaging and treatment personalization, while potential disadvantages include treatment-related toxicity and the risk of delaying definitive local therapy in non-responders. Adjuvant therapy emphasizes eliminating residual disease after surgery but may add toxicity without clear benefit in some patients. Individualization through multidisciplinary care is essential.