Trastuzumab therapy and new-onset hypertension in adolescents and young adults with breast cancer.

BACKGROUND

Trastuzumab therapy carries a risk of acute cardiotoxicity, particularly when combined with anthracyclines. To date, no study has assessed hypertension as a potential long-term adverse effect of trastuzumab therapy in adolescent and young adult (AYA) cancer survivors.

METHODS

We identified all female AYAs aged 15-39 years diagnosed with first primary invasive breast cancer between 2006 and 2020 in Kaiser Permanente Northern and Southern California, who survived at least 2 years post-diagnosis. Patients were categorized into two groups: those who received chemotherapy plus trastuzumab and those who received chemotherapy alone. We examined hypertension occurrence starting 2 years post-diagnosis, compared the 2-5-year cumulative incidence of hypertension between the trastuzumab and non-trastuzumab groups, and evaluated associated risk factors.

RESULTS

Among 2382 female AYAs with breast cancer, 33.0% received trastuzumab. The 2-5-year cumulative incidence of hypertension did not differ between the trastuzumab (6.79%, 95% Confidence Interval [CI] 4.96-8.99%) and non-trastuzumab (7.85%, CI 6.41-9.48%) groups, p = 0.67. Trastuzumab was not associated with hypertension (hazard ratio (HR) = 1.01, CI 0.731-1.38) in multivariable analysis. Factors associated with higher hypertension included older age at diagnosis (35-39 vs. 15-34y), non-Hispanic Black or non-Hispanic Asian race/ethnicity (vs. non-Hispanic White), overweight or obesity (vs. underweight or normal weight), smoking, and endocrine therapy. History of diabetes and dyslipidemia showed borderline association with hypertension.

CONCLUSION

Trastuzumab was not associated with new-onset hypertension among AYA breast cancer survivors. However, sociodemographic and clinical factors significantly contributed to hypertension risk, highlighting the importance of interventions targeting modifiable risk factors.