The impact of young age at diagnosis (age <40 years) on prognosis varies by breast cancer subtype: A U.S. SEER database analysis

Abstract

Purpose: Women under 40 years old are at increased risk for developing human epidermal growth factor receptor 2 (HER2) positive or triple negative subtype and more advanced breast cancer, yet young age itself has also historically been an independent prognostic factor. Methods: Using the Surveillance, Epidemiology, and End Results (SEER) Program, we examined data for 271,173 women with stage I-III breast cancer between 2010 and 2015. Using Fine and Gray regression models to account for competing risks, we examined the risk of breast cancer-specific death by age and clinical subtypes, considering grade, hormone receptor (HR) and HER2 status, adjusting for demographic, clinical and treatment variables. Results: Of 271,173 women eligible for analysis, 14,109 were 75 had increased breast cancer mortality in all subtypes. Conclusion: With modern clinical subtyping, age under 40 remains independently associated with worse outcomes in 30 months follow-up only in HR-positive, lower grade disease.

Keywords

• Breast cancer
• Young women
• Age
• Outcomes
• Subtype