International Journal of Health Policy and Management

International Journal of Health Policy and Management

Robotic Surgical System Adoption and Radical Prostatectomy Volume in Japan: A Nationwide Hospital-Level Longitudinal Difference-in-Differences Study

Document Type : Original Article

Authors
1 Health Technology Assessment Unit, Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan
2 Department of Urology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
3 Department of Next-Generation Organ Transplantation, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
4 Graduate School of Business Administration, Keio University, Yokohama, Japan
5 Graduate School of Health Management, Keio University, Fujisawa, Japan
Abstract
Background
Robotic-assisted radical prostatectomy (RARP) has become the dominant approach for prostate cancer surgery, replacing open and laparoscopic procedures. However, whether the introduction of robotic surgical systems has increased the overall number of radical prostatectomies (RPs) remains unclear, particularly within social health insurance systems.

Methods
We conducted a nationwide longitudinal observational study using hospital-level data from Japan between 2016 and 2023. Hospitals performing at least one RP annually and reporting complete data on robotic surgical system status and RP volume across the study period were included in the primary analysis. The primary outcome was the annual number of RPs per hospital. Using a staggered difference-in-differences (DID) design, we compared hospitals that adopted robotic surgical systems with hospitals that had not yet adopted them and estimated the association between adoption and annual hospital-level RP volume.

Results
A total of 288 hospitals were categorized as 189 previous adopters, 77 new adopters, and 22 non-adopters. New adopters demonstrated a sustained increase in RP volume, rising from 2608 procedures in 2016 to 4371 in 2023, whereas RP volumes among previous adopters and non-adopters remained stable. Compared with hospitals that had not yet adopted robotic surgical systems, adoption was associated with an increase of 17.4 RPs per hospital per year (95% CI, 10.7 to 24.1). No significant differences were observed between groups during the pre-adoption period, consistent with the parallel trends assumption.

Conclusion
In Japan’s social health insurance context, adoption of robotic surgical systems was associated with a significant and sustained rise in RP volume. These findings highlight the need for further research to determine whether the observed increase reflects changes in patient selection, referral patterns, clinical appropriateness, or other mechanisms, as well as the associated clinical and economic implications.
Keywords

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Volume 15, Issue 1
2026
Pages 1-9

Supplementary File
(IJHPM does not take responsibility for any information provided in the supplementary files.)

  • Received Date 02 November 2025
  • Revised Date 23 June 2026
  • Accepted Date 11 August 2026
  • First Published Date 22 August 2026
  • Published Date 01 December 2026