Purpose: It’s understood that younger women face a greater chance of having aggressive forms of breast cancer. While past research indicates a higher likelihood of breast cancer returning and lower survival rates for young women with early-stage breast cancer, the specific role of tumor subtype in these outcomes hasn’t been fully explored. This study aims to investigate how Age Of Diagnosis affects breast cancer survival, taking into account different tumor subtypes.
Methods: Data was collected from women newly diagnosed with stage I to III breast cancer. These women were treated at eight National Comprehensive Cancer Network centers between January 2000 and December 2007. To analyze the link between age and breast cancer-specific survival, researchers used multivariable Cox proportional hazards models. This statistical method allowed them to assess the impact of age of diagnosis while considering other factors.
Results: The study included 17,575 women with stage I to III breast cancer. Among them, 1,916 were 40 years or younger when diagnosed, highlighting the significance of age of diagnosis. The median follow-up period was 6.4 years. After controlling for various sociodemographic factors, disease characteristics, and treatments, the results showed that women diagnosed at age 40 or younger had a 1.4 times higher hazard ratio (HR) for breast cancer mortality (95% CI, 1.2 to 1.7). This indicates a significantly increased risk associated with younger age of diagnosis.
Further analysis, stratified by tumor subtype, revealed that age of diagnosis ≤ 40 was linked to statistically significant increases in breast cancer death risk for women with luminal A (HR, 2.1; 95% CI, 1.4 to 3.2) and luminal B (HR 1.4; 95% CI, 1.1 to 1.9) tumors. There was also a borderline significant increase in risk for those with triple-negative tumors (HR, 1.4; 95% CI, 1.0 to 1.8). However, no significant association was found between younger age of diagnosis and increased mortality in women with human epidermal growth factor receptor 2 (HER2) subtypes (HR, 1.2; 95% CI, 0.8 to 1.9).
Interestingly, when considering the method of detection, younger age of diagnosis was only significantly associated with increased breast cancer death risk in women with luminal A tumors. This suggests that for this specific subtype, age of diagnosis plays a particularly critical role.
Conclusion: The study concludes that the effect of age of diagnosis on breast cancer survival is not uniform and varies depending on the breast cancer subtype. Younger age of diagnosis appears to be a particularly strong prognostic factor for women with luminal breast cancers, especially luminal A. These findings emphasize the importance of considering tumor subtype when assessing prognosis and tailoring treatment strategies for younger women diagnosed with breast cancer. Understanding the nuances of how age of diagnosis interacts with tumor subtype is crucial for improving outcomes in young women facing this disease.
