Pathology of neoadjuvant therapy and immunotherapy testing for breast cancer.
Histopathology
; 82(1): 170-188, 2023 Jan.
Article
in English
| MEDLINE | ID: covidwho-2161606
ABSTRACT
Neoadjuvant chemotherapy (NACT) has become the standard of care for high-risk breast cancer, including triple-negative (TNBC) and HER2-positive disease. As a result, handling and reporting of breast specimens post-NACT is part of routine practice, and it is important for pathologists to recognise the changes in tumour cells, tumour-associated stroma and background breast tissue induced by NACT. Familiarity with characteristic stromal features enables identification of the pre-treatment tumour site and allows confident diagnosis of pathological complete response (pCR) which is important for decisions concerning adjuvant therapy. Neoadjuvant endocrine therapy (NAET) is used less frequently than NACT; however, the SARS-COVID-19 pandemic has changed practice, with increased use as bridging therapy if surgery is delayed. NAET also induces characteristic changes in the tumour and stroma. Changes in the tumour microenvironment following NACT and NAET are also described. Immunotherapy is approved for use in advanced TNBC, and there are several trials exploring its role in early TNBC in the neoadjuvant setting. The current biomarker to determine eligibility for treatment with immune checkpoint inhibitors is programmed death ligand-1 (PD-L1) immunohistochemistry; however, this is complicated by lack of standardisation with different drugs linked to tests using different antibodies with different scoring systems. The situation in the neoadjuvant setting is further complicated by improved pCR rates for PD-L1-positive tumours in both immune therapy and placebo arms. Alternative biomarkers are urgently needed to identify which patients will derive benefit from immunotherapy and key candidates are discussed.
Keywords
Full text:
Available
Collection:
International databases
Database:
MEDLINE
Main subject:
Breast Neoplasms
/
COVID-19
Type of study:
Diagnostic study
/
Prognostic study
/
Randomized controlled trials
Limits:
Female
/
Humans
Language:
English
Journal:
Histopathology
Year:
2023
Document Type:
Article
Affiliation country:
His.14771
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