Different prognosis of left compared to right breast cancer: A systematic review and meta-analysis

Area of Science:

• Oncology
• Cardiology
• Biostatistics

Background:

• The laterality of breast cancer (left vs. right) is debated regarding its impact on patient outcomes.
• Understanding survival disparities is crucial for personalized treatment strategies and risk assessment.

Purpose of the Study:

• To evaluate differences in overall survival (OS), cardiac mortality, and cancer-specific survival (CSS) between left-sided and right-sided breast cancer.
• To provide evidence-based insights into the prognostic implications of breast cancer laterality.

Main Methods:

• A comprehensive meta-analysis was performed, searching PubMed, EMBASE, and Cochrane Library databases up to December 1, 2023.
• Included 50 publications encompassing 7,527,156 patients.
• Primary endpoint was OS; secondary endpoints included cardiac mortality and CSS.

Main Results:

• Left-sided breast cancer was associated with marginally decreased OS (HR=1.03, P<.01).
• A significant 10% increase in cardiac mortality was observed for left-sided BC (HR=1.1, P<.01).
• Cancer-specific survival (CSS) showed no significant difference between left and right-sided breast cancer (HR=1.01, P=.32).

Conclusions:

• Left-sided breast cancer presents a slightly increased risk of mortality and a notable rise in cardiac-related deaths compared to right-sided BC.
• While CSS is similar, the increased cardiac mortality highlights a potential specific vulnerability associated with left-sided tumors.