pathologic complete response
Also written as: pCR — Pathologic Complete Response
Absence of invasive cancer cells in surgical specimens following neoadjuvant therapy, indicating excellent treatment response.
Full Definition
Pathologic complete response (pCR) is defined as the absence of residual invasive cancer in the primary tumor bed and regional lymph nodes following neoadjuvant (pre-surgical) treatment, as determined by microscopic examination of surgical specimens. This finding represents an optimal response to systemic therapy and is associated with improved long-term outcomes in many cancer types. The specific criteria for pCR may vary by cancer type and institutional protocols, particularly regarding the presence of non-invasive cancer components such as ductal carcinoma in situ. Achieving pCR is increasingly used as a surrogate endpoint in clinical trials and as a quality metric for neoadjuvant treatment programs, requiring standardized pathologic assessment and reporting procedures.
Usage
Usage note: Use lowercase 'p' in 'pCR' abbreviation; distinguish from clinical complete response which is based on imaging rather than histology.
In Context
- "The pathology report confirmed pathologic complete response with no residual invasive carcinoma." — Post-surgical pathology report
- "Pathologic complete response rates served as the primary endpoint for the neoadjuvant study." — Clinical trial protocol