As a successful curative therapy for locally advanced prostate cancer (PC), stereotactic body radiation therapy (SBRT) has increasingly gained popularity. However, the high incidence of erectile dysfunction (ED) following conventional photon-based SBRT continues to be a problem and has a significant negative impact on the quality of life for PC survivors. Modern proton treatment allows for better conformal SBRT delivery and has the potential to lower the incidence of ED, but its cost-effectiveness has not been well studied.

A Markov decision model was created to compare the cost-effectiveness of proton SBRT with photon SBRT in minimizing irradiation-related ED. A localized PC patient with healthy erectile function prior to therapy, aged 66 (median age of PC), underwent base-case analysis. Additionally, stratified analyses for various age brackets (50, 55, 60, 65, 70, and 75 years) and threshold studies to determine cost-effective scenarios were carried out. Finally, a willingness-to-pay (WTP) threshold of 37,653 US dollars ($)/quality-adjusted life year (QALY) was chosen by the society.

Protons increased the number of QALYs by 0.152 in the base case at an additional cost of $7233.4, with a cost-effectiveness ratio of $47,456.5 per QALY. For patients aged ≤62 and older at the WTP, protons were cost-effective (≤ 66-year-old at a WTP of $50,000/QALY and ≤ 73-year-old at a WTP of $100,000/QALY). Protons were cost-effective at the WTP of patients at the median age after the current proton cost ($18,000) was decreased to  ≤$16,505.7 or the patient’s life expectancy was increased to ≥88 years.

According to assumption-based modeling, the study’s findings suggested using proton SBRT in younger localized PC patients who were previously potent for greater erectile function preservation, according to assumption-based modeling. The results need to be confirmed with data from upcoming comparative clinical studies.