Hypertension and clinical outcomes following thoracic radiotherapy.
Abstract
Background
Radiation therapy (RT) is highly efficacious in treating thoracic malignancies. However, RT has been linked to potential cardiotoxicity. Yet, the long-term incidence, severity, and implications of HTN-development post-RT are unknown.
Methods
Leveraging a large US-based Comprehensive-Cancer-Center-cohort of patients treated with thoracic-RT from 2007 to 2019, we included patients ≥18 years old with histologically confirmed esophageal or lung cancers. The primary outcome was incidence of incident/new or worsened HTN [systolic-blood-pressure-(SBP) ≥130 mmHg] after RT-initiation. The secondary outcomes were major-adverse-cardiac-events (MACE- heart-failure, myocardial-infarction, arrhythmia, stroke, and sudden-death), disease-progression, and overall-survival, by HTN-status. Differences in outcomes by HTN-status were also evaluated via landmark-analysis, excluding those with undiagnosed HTN. Observed new HTN rates were compared to Framingham-predicted-rates, and absolute-excess-risks were estimated. Multivariate regression was used to define the relation between clinical and RT measures and both new or worsened HTN-development and survival-outcomes.
Results
Overall, 439 RT-treated patients (238 esophageal; 201 lung; 66.7% male; mean age 63.6 years; 65% baseline HTN) were identified. Over a median follow-up of 23 months, 255 (58.1%) developed new or worsened HTN; median SBP increase of 7 mmHg. In landmark-analysis, the cumulative incidence of new or worsened HTN by 1-year was 48.0% and 63.4%, respectively. Using the JNC-8 cutoff of ≥140/90 mmHg, the new HTN rate was 21.6% at 1-year, translating to a 3.4-fold higher rate than the Framingham-predicted-rate (RR 3.37, P < 0.001). In multivariate regression, RT-dose was consistently associated with new or worsened HTN-development (P < 0.05); those with RT-induced-HTN saw improved progression-free-survival and overall-survival (HR 0.67 and 0.54, P < 0.01, respectively). Beyond traditional factors, only RT-dose is consistently associated with MACE (P < 0.05). No specific antihypertensive class prevented RT-related HTN.
Conclusions
These data suggest that thoracic-RT increases early HTN risk.