Second Opinion Referrals of Cancer Patients in Japan-A Nationwide Study

Seeking a second opinion (SO) is a patient's right that is essential to appropriate decision-making for their care and treatment. In Japan, however, no previous studies have provided objective data on the nationwide practice of SO among cancer patients. In this study, we investigated SO referrals, including delays in initiating care, using data from nationwide hospital-based cancer registries and 2018-2020 the Diagnosis Procedure Combination (DPC) survey. Among the more than 2.6 million patients diagnosed with cancer, 1.6% received SO referral letters as reimbursement. The referral rates varied based on sex, age, and geographic regions. A total of 52.1% of SO were sought before active treatment of the tumor. Approximately 60% of the patients who sought SO prior to the initial treatment returned to their original provider for treatment. The average period from diagnosis to the start of treatment among those who sought SO was 18 days and 22 days longer for non-small lung cancer and breast cancer, respectively, than among those who did not seek SO. In the future, the risk-benefit of SO referral should be examined, considering both the prognostic impact of treatment delay due to SO and the psychological benefits for the patient gained from SO.