A model-based analysis reported in JACC: CardioOncology by Busschaert et al suggested that the heart-sparing deep inspiration breath-hold vs free-breathing radiation therapy technique is cost-effective—despite increasing treatment time—and may improve the long-term cardiovascular health of patients with left-sided breast cancer.

“With the deep inspiration breath-hold technique, patients hold their breath during radiation therapy, effectively displacing the heart from the radiation field,” the investigators remarked. “The superior dosimetric performance of [this heart-sparing technique] over free breathing has been confirmed in a meta-analysis, … [but] financial investments and the potential impacts on workflow represent significant barriers to widespread implementation.”

Study Details

A total of 100 consecutive retrospective Belgian patients with left-sided breast cancer who underwent radiation therapy using the deep inspiration breath-hold technique and had an available free-breathing computed tomography (CT) scan were eligible for the analysis.

The investigators developed treatment plans using the deep inspiration breath-hold and free-breathing techniques for each member of this eligible population. The mean heart dose and other dosimetric data were calculated for both techniques to estimate the cardiotoxicity of radiation therapy. A systematic Coronary Risk Evaluation (SCORE2) algorithm–based state-transition microsimulation model was used to project the effects of the deep inspiration breath hold on cardiovascular outcomes and quality-adjusted life-years.

The investigators determined costs from a provider perspective via time-driven activity-based costing, applying a willingness-to-pay threshold of €40,000 (approximately $43,300 USD) to evaluate cost-effectiveness. Using a discrete event simulation model, they assessed the impacts of the deep inspiration breath-hold vs free-breathing techniques on throughput and waiting times in the radiation therapy workflow.

According to the investigators, the primary outcome of the study was to quantify the quality-adjusted life-years gained using the deep inspiration breath-hold technique; in accordance with Belgian national guidelines, they were discounted at a rate of 1.5% per annum. The absolute risk reductions in both nonfatal and fatal cardiovascular disease events were evaluated as secondary outcomes. Other outlined study outcomes included the number needed to treat and the cost-effectiveness of the deep inspiration breath-hold technique.

Benefits of Deep Inspiration Breath Hold

In the base-case scenario, over 20 years, the deep inspiration breath-hold technique seemed to be associated with an average absolute risk reduction of 1.7% in total cardiovascular events (95% confidence interval [CI] = 1.7%–1.8%) and 0.7% in fatal cardiovascular events (95% CI = 0.7%–0.7%). Regarding the numbers needed to treat, the investigators found that 58 (95% CI = 57–60) and 144 (95% CI = 138–150) patients must use the heart-sparing technique to prevent one fatal or nonfatal cardiovascular event and one cardiovascular death, respectively. The application of the deep inspiration breath-hold technique also resulted in an average gain of 0.04 quality-adjusted life-years per patient over the same 20-year horizon (95% CI = 0.04–0.05), which appeared to be attributed to reductions in cardiovascular morbidity and mortality.

Costs of Deep Inspiration Breath Hold

The deep inspiration breath-hold technique increased treatment times, reducing the maximum achievable throughput by 12.5% (95% CI = 12.4%–12.8%) and increasing the mean cost per patient by €617 (approximately $668 USD; 95% CI = €615–€619). According to the investigators, the per-patient expense rose because of the capital investment required for implementing this heart-sparing technique, as well as the higher demand for the linear accelerator, CT scanner, and radiation treatment technicians. An incremental cost-effectiveness ratio of €14,023 (approximately $15,179 USD) per quality-adjusted life-year was documented.  

“Our results suggest that the application of the deep inspiration breath-hold technique is cost-effective in the Belgian population, reducing both cardiovascular morbidity and mortality,” the investigators concluded. “However, radiation oncologists must consider the increased demands [this heart-sparing technique] places on resources to prevent delays in patient care.”

They acknowledged the need for prospective clinical research and data collection to validate their findings. Furthermore, the investigators proposed that future research examine the generalizability of operational and financial implications observed in this study to other radiation therapy departments, and assess the applicability of conclusions regarding patient outcomes in diverse breast cancer populations.

Sara-Lise Busschaert, MSc, of Vrije Universiteit Brussel, Brussels, Belgium, is the corresponding author of the JACC: CardioOncology article.

Disclosure: The study was funded by Vrije Universiteit Brussel. For full disclosures of the study authors, visit jacc.org.