NAC
Also written as: NAC — neoadjuvant chemotherapy
Chemotherapy administered before surgery to shrink tumor size and assess treatment response.
Full Definition
Neoadjuvant chemotherapy (NAC) refers to systemic cancer treatment given prior to the primary surgical intervention. In breast oncology, NAC is used to reduce tumor size, potentially allowing for breast-conserving surgery instead of mastectomy, and to evaluate tumor response to specific chemotherapy regimens. The pathologic response to NAC provides important prognostic information and may guide subsequent treatment decisions. NAC is particularly common in locally advanced breast cancers and certain aggressive subtypes where immediate surgery may not be optimal.
Usage
Usage note: Always spell out on first use in patient-facing documents. Distinguish from adjuvant therapy which occurs after surgery.
In Context
- "The patient completed six cycles of NAC with excellent clinical response." — Clinical progress note
- "Following NAC, the tumor was downstaged from T3 to T1." — Surgical consultation report