Locoregional Recurrence Following Breast Cancer Surgery in the Trastuzumab Era: A Systematic Review by Subtype

Area of Science:

• Oncology
• Breast Cancer Research
• Molecular Subtyping

Background:

• Molecular subtype is increasingly recognized as a factor influencing breast cancer locoregional recurrence (LRR).
• Previous reviews predated Trastuzumab therapy, necessitating an updated assessment in the current treatment landscape.
• This study evaluates the impact of molecular subtype on LRR in patients treated with Trastuzumab.

Purpose of the Study:

• To assess the quantitative influence of distinct breast cancer molecular subtypes on LRR.
• To provide an updated analysis considering contemporary treatment regimens, including Trastuzumab.
• To compare LRR rates across luminal A, luminal B, HER2/neu-overexpressing, and triple-negative breast cancer subtypes.

Main Methods:

• A systematic review of published studies was conducted.
• Inclusion criteria focused on studies reporting LRR data stratified by breast cancer subtype in patients treated with Trastuzumab.
• Data extraction focused on LRR rates and statistical comparisons between subtypes.

Main Results:

• Analysis of 11,219 patients from seven studies revealed an overall LRR rate of 3.44%.
• Luminal A subtypes exhibited the lowest LRR (1.7%), whereas triple-negative breast cancer showed the highest rates (7.4%).
• Significantly lower LRR risks were observed for luminal A, HER2/neu-overexpressing, and triple-negative subtypes compared to luminal B, with notable differences also between HER2/neu-overexpressing and triple-negative groups.

Conclusions:

• Substantial variations in LRR exist across breast cancer molecular subtypes.
• Luminal breast cancers demonstrate the lowest LRR, while triple-negative subtypes present the highest risk.
• The observed low LRR rates underscore significant advancements in contemporary breast cancer management.