pathologic complete response
Also written as: pCR — pathologic complete response
The absence of residual invasive cancer in the surgical specimen after neoadjuvant therapy.
Full Definition
Pathologic complete response (pCR) is defined as the absence of residual invasive cancer in the primary tumor site and regional lymph nodes following neoadjuvant therapy, as determined by histopathological examination of the surgical specimen. The presence of residual carcinoma in situ may or may not be included in the pCR definition, depending on the cancer type and study protocol. pCR is considered a strong surrogate endpoint for long-term outcomes in several cancer types, particularly breast cancer and rectal cancer. Achievement of pCR is associated with improved disease-free survival and overall survival, making it a valuable prognostic indicator and regulatory endpoint for drug approval.
Usage
Usage note: Can be abbreviated as pCR. Distinguish from complete clinical response, which is based on imaging.
In Context
- "The patient achieved pathologic complete response following neoadjuvant chemotherapy." — Pathology report
- "pCR rates were significantly higher in the experimental treatment arm (45% vs 30%)." — Clinical trial results