Time to Treatment Initiation for Six Cancer Types: an Analysis of Data from a Nationwide Registry in Japan

Background Delay in the time to treatment initiation (TTI) may adversely affect the survival of patients, but its current status in Japan is unknown. This study aims to describe the TTI for six cancer types: lung, breast, colorectal, stomach, head and neck (H&N), and cervical. Data for this study were derived from a nationwide registry in Japan. Methods This observational study employed the national database of hospital-based cancer registries (HBCRs) and health services utilization data. Using HBCR data, we identified all patients with cancer who started their cancer therapy at the same hospitals between January 1 and December 31, 2017. We calculated the TTI for each cancer type and treatment option, stratifying the results by age group and geographical region. Results The overall median TTI was 33 days, with shorter TTIs for colorectal and H&N cancers and chemotherapy. The TTI was the shortest for younger patients and the longest for the elderly, especially for lung cancer. When categorized by eight Japanese geographical regions, Tohoku and Kanto had the longest TTI. The result remained the same even after adjusting cancer type, treatment, age, and stage information. Conclusion For colorectal and H&N cancers, in which a longer TTI is associated with a poorer prognosis, TTI was found to be particularly shorter. Although we could not discuss our results in light of the patient survival in this study, future research should explore the best balance between thorough evaluation before treatment and necessary time for that.