News
Five-Year Overall Survival after Robot-Assisted Rectal Cancer Surgery Analyzed Using Medical Big Data By Dr. Marie Hanaoka and colleagues, Department of Gastrointestinal Surgery, Institute of Science Tokyo
- January 16, 2026
A research group led by Dr. Marie Hanaoka of the Department of Gastrointestinal Surgery at Institute of Science Tokyo analyzed the five-year overall survival (OS) for patients with stage II and III advanced rectal cancer using one of Japan’s largest medical databases owned by Medical Data Vision Co., Ltd. (Chiyoda-ku, Tokyo; President and CEO: Hiroyuki Iwasaki; hereafter “MDV”). The analysis demonstrated that robot-assisted surgery was associated with significantly better outcomes compared with laparoscopic surgery and open surgery.
This study is a multicenter retrospective cohort study analyzing medical data held by MDV. Among 37,191 patients who underwent rectal resection between April 2018 and June 2024, the analysis focused on 17,793 patients with rectal cancer classified as cT3, in which the tumor has invaded the subserosal layer, and cT4a, in which the tumor has penetrated beyond the rectal wall, based on the clinical T classification (cT classification*), which indicates the stage of rectal cancer.
*The cT classification is an indicator used in the clinical staging prior to treatment initiation that describes the extent and size of the primary tumor.
The five-year overall survival (OS) was highest in the robot-assisted surgery group, followed by laparoscopic surgery and open surgery. In terms of short-term outcomes, robot-assisted surgery showed the lowest incidence of postoperative complications. In addition, patients who underwent robot-assisted surgery had the shortest length of hospital stay, and the total medical costs from hospitalization to discharge were also the lowest, indicating a reduced financial burden on patients and their families.
Dr. Hanaoka
from the research group
This study was conducted by a research group led by Dr. Marie Hanaoka and Dr. Yusuke Kinugasa from the Department of Gastrointestinal Surgery at Institute of Science Tokyo. The original research article has been published in Colorectal Disease.
The original article is available here: https://onlinelibrary.wiley.com/doi/10.1111/codi.70278
MDV’s medical database covers 55.02 million real-world patients as of the end of December 2025 and is widely used as real-world data (RWD*²) in research by clinicians and academic institutions, including studies aimed at validating hypotheses in real-world clinical practice.
² Real-world data (RWD) refers to health and medical data collected from everyday life and actual clinical settings, rather than from controlled environments such as clinical trials.
For an interview with Dr. Hanaoka, please refer to the following column (Japanese only)
Medical Big Data Contributing to Clinical and Pharmaceutical Research #8
URL：https://www.mdv.co.jp/ebm/column/medical-big-data/article131/
QR code for the column