Five-year conditional relative survival up to 10 years post-diagnosis among adolescent and young adult breast cancer patients by age, stage, and receptor subtype.

BACKGROUND

Conditional relative survival (CRS), the probability of survival given that an individual has already survived a certain period post-diagnosis, is a more clinically relevant measure for long-term survival than standard relative survival (RS). This study aims to evaluate the 5-year CRS among adolescent and young adult (AYA) breast cancer patients by age, tumor stage, and receptor subtype to guide disclosure periods for insurance.

METHODS

Data of all females aged 18-39 years and diagnosed with invasive breast cancer between 2003 and 2021 ( = 13,075) were obtained from The Netherlands Cancer Registry (NCR). The five-year CRS was calculated annually up to 10 years post-diagnosis using a hybrid analysis approach.

RESULTS

For the total AYA breast cancer study population the 5-year CRS exceeded 90 % from diagnosis and increased beyond 95 % 7 years post-diagnosis. Patients aged 18-24 reached 95 % 9 years post-diagnosis, those aged 25-29 after 5 years, and those aged 30-34 and 35-39 after 8 years. For stage I, the 5-year CRS reached 95 % from diagnosis, for stage II after 6 years, while the 5-year CRS for stages III and IV did not reach the 95 % threshold during the 10-year follow-up. Triple-negative tumors exceeded 95 % after 4 years, human epidermal growth factor receptor 2 (HER2) positive tumors after 6 years, while hormone receptor (HR) positive tumors did not reach 95 %.

CONCLUSION

Excess mortality among AYA breast cancer patients tends to be little (CRS 90 %-95 %) from diagnosis and becomes minimal (CRS>95 %) over time compared to the general population. These results can enhance expectation management and inform policymakers, suggesting a shorter disclosure period.