by Matthew G. Davey, Ciara M. Davey, Luis Bouz, Eoin Kerin,
Carson McFeetors, Aoife J. Lowery, Michael J. Kerin
The Breast: VOLUME 64, P41-46, AUGUST 01,
2022 (Published: April 28, 2022)
Introduction
The 21-gene assay provides prognostication for estrogen
receptor positive, human epidermal growth factor receptor-2 negative
(ER+/HER2-) early female breast cancer patients. This signature has not been
validated in male breast cancer (MBC).
Methods
A systematic review and meta-analysis was performed in
accordance to the PRISMA guidelines. Retrospective cohort studies comparing
21-gene assay scores in female and MBC were included. Dichotomous variables
were pooled as odds ratios (OR) and associated 95% confidence intervals (CI)
using the Mantel–Haenszel method.
Results
Six studies including 176,338 patients were included (mean
age of 63.4 years, range: 33–88). Of these, 1.0% had MBC (1826/176,338) and
99.0% were female patients (174,512/176,338). MBC patients were more likely to
have increased tumour stage, nodal involvement, and grade 3 disease (all P < 0.001)
In MBC patients, the mean score was 18.8 (range: 11–26) vs. 13.4 (range 0–33)
in female patients (P < 0.001). In MBC patients, 22.4% had scores
>30 (408/1822) versus 18.3% in female patients (31,852/174,500). In female
patients, 52.0% had scores <18 (90,787/174,500) versus 47.8% in MBC
(471/1822). Overall, patients with female patients were as likely to have
scores <18 (OR: 1.04, 95% CI: 0.94–1.16), scores 18–30 (OR: 1.12, 95% CI:
1.00–1.26) and scores >30 (OR: 0.69, 95% CI: 0.45–1.07) as MBC patients.
Conclusion
There are similar anticipated scores for female and MBC
undergoing 21-gene expression assay testing for early stage, ER+/HER2-breast
cancer. In the absence of stage matching, cautious interpretation of these
results is required. Validation of the 21-gene assay in MBC is still required.
Keywords
