Abstract Background The increasing incidence and prevalence of breast cancer alongside diagnostic and treatment technology advances have produced a debate about the financial burden cancer places on the healthcare system and concerns about access. Methods This study was conducted at 51 hospitals belonging to the Breast Cancer Study Group of the Japan Clinical Oncology Group using a web-based survey. The survey period conducted from July 2021 to June 2022. The study population included patients with metastatic breast cancer who received the related treatment as their first-line therapy. The proportion of patients who selected that regimen as their first-line treatment was tabulated. The total cost increase for each current standard therapy in comparison to conventional treatments was calculated. Results A total of 702 patients (pts) were surveyed. Of those enrolled, 342 (48.7%) received high-cost treatment [estimated monthly drug costs exceeding ~500 000 Japanese Yen (JPY)]. Of these, 16 pts (4.7%) were receiving very high-cost treatment, amounting to more than 1 000 000 JPY per month. Fifty three (15.5%) of the patients who received high-cost treatment were 75 years of age or older. Of these, 1 pt (0.3%) were receiving very high-cost treatment. Analyses of incremental costs by current drugs showed that abemaciclib was costly with total additional cost of 6 365 670 JPY per patient. The total additional cost of the regimen per patient that included palbociclib was the second highest at 4011248 JPY, followed by atezolizumab at 3209033 JPY. Conclusions The findings indicate that evaluating the financial implications of high-cost treatments requires considering not only drug prices but also analysis of total cost increase.

Status of incremental costs of first-line treatment recommended in Japanese clinical guidelines for metastatic breast cancer patients