Background Gastrointestinal bleeding is a major complication of dual antiplatelet therapy (DAPT) in patients undergoing percutaneous coronary intervention (PCI). Malignancy may be detected due to gastrointestinal bleeding, necessitating critical decisions regarding treatment selection and influencing patient prognosis. This study investigated the frequency of gastrointestinal malignancies, associated factors, and prognoses in patients undergoing perioperative PCI through upper and lower gastrointestinal endoscopy. Methods This single-center, retrospective, observational study included 501 Japanese patients who underwent initial PCI between January 2019 and January 2023. Of these patients, 393 who underwent perioperative upper and lower gastrointestinal endoscopy were evaluated for the presence of gastrointestinal malignancy. Results Of the total patients, 36% presented with acute coronary syndrome (ACS). Gastrointestinal malignancies were identified in 30 patients (8%), including 18 cases of colorectal cancer and eight cases of gastric cancer. No difference in the frequency of malignancies was observed between patients with ACS and chronic coronary syndrome (CCS) (p = 0.7398). Malignancies were significantly more common in patients with positive faecal immunochemical testing (FIT) (p < 0.0001); however, FIT did not detect all malignancies. The 1500-day survival rate for patients with gastrointestinal malignancies was 64%, with no difference in overall survival between treatment modalities. Conclusions A considerable proportion of Japanese patients undergoing PCI had gastrointestinal malignancies, regardless of whether they had ACS or CCS, and their prognosis was poor. Upper and lower gastrointestinal endoscopic evaluations should be conducted, including for ACS cases, to prevent DAPT-induced gastrointestinal bleeding and improve prognosis.

The authors have declared no competing interest.

This study did not receive any specific grants from funding agencies in the public, commercial, or non-profit sectors.

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

The Institutional Review Board of National Hospital Organization Hakodate Medical Center (No.1105002)

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