Evaluating the effectiveness of treatment cost calculation tool in improving patients' understanding of drug costs in advanced breast cancer: A multicenter, randomized controlled trial.

e13566 Background: In breast cancer, the prognosis has improved with the introduction of new drugs; however, due to their high cost, patients are facing increased out-of-pocket expenses, leading to a new issue known as 'financial toxicity.' Additionally, there have been reports of insufficient cost communication between healthcare providers and patients. This study aimed to evaluate the effectiveness of explaining medical costs using the ChemoCalc application, a treatment cost calculation tool, in patients with advanced breast cancer (ABC). Methods: We conducted a multicenter, randomized, controlled phase II trial. Patients with ABC, who are starting or changing drug therapy, and have two or more treatment options presented by the attending physician were allocated in a 1:1 ratio to the ChemoCalc and non- ChemoCalc groups. The sample size was set to 116 cases. In the ChemoCalc group, the treatment plan for ABC was discussed using ChemoCalc, while in the non- ChemoCalc group, the treatment plan was discussed without using ChemoCalc, following the usual approach of the attending physician. The primary endpoint was the comparison of scores of two key questions in the questionnaire between the two groups: “Did you understand the drug cost in today' s discussion?” and “Do you think the drug cost is important when deciding on treatment?”. The questions were rated on a five-point scale, with 1 being “not at all” and 5 being “very much". Results: Due to the company's discontinuation of ChemoCalc, the enrollment was completed with 70 cases. Of these, both the ChemoCalc group and the non- ChemoCalc group had 35 cases enrolled. In the ChemoCalc group, the scores for understanding drug costs in the patient survey were higher compared to the non-ChemoCalc group. On the other hand, no difference was observed between the two groups in the patient survey regarding the importance of medical costs in treatment, with the median score being the highest possible score of 4 in both groups. In the patient survey regarding who patients would like to consult about the financial burden, the most common response was with “physician”. In the patient survey asking which factors are most important in treatment selection, the highest scores were given to drug efficacy and side effects. Regarding costs, in the COST questionnaire, which evaluates financial toxicity rather than out-of-pocket expenses, the group with higher financial toxicity had higher scores for drug costs. Conclusions: The patient survey results showed that the use of ChemoCalc in patients with ABC improved patients' understanding of drug costs. Patients expressed a desire to discuss financial burdens with their physicians, and the use of a drug cost calculator tool is beneficial. Clinical trial information: UMIN000039904 .