Perioperative adverse events in women undergoing concurrent urogynecologic and gynecologic oncology surgeries for suspected malignancy Abstract Introduction and hypothesis This study’s objectives were to compare the incidence of adverse events after concurrent urogynecologic and gynecologic oncology surgery to gynecologic oncology surgery alone and to describe the frequency of modification in planned urogynecologic procedures. The authors hypothesized there would be no difference in major complications. Methods This was a retrospective matched cohort study of women who underwent concurrent surgery at a large tertiary care center between January 2004 and June 2017. Cohorts were matched by surgeon, surgery route, date, and final pathologic diagnosis. Perioperative data and postoperative adverse events classified by Clavien-Dindo grade were compared. Results One hundred and eight patients underwent concurrent surgeries, with 216 matched cohorts. Concurrent-case patients were more likely to be older, postmenopausal, have greater vaginal parity, have had preoperative chemotherapy, and have preoperative cardiac or pulmonary disease. There were no differences in intraoperative complications or Dindo grade ≥ 3 adverse events between groups, but there were more grade 2 adverse events in the concurrent cohort (44 vs 19%, p < 0.0001) including postoperative urinary tract infection (UTI) (26 vs 7%, p < 0.0001). Concurrent surgery remained associated with a higher incidence of grade ≥ 2 events on multivariate analysis [odds ratio (OR) 2.5, 95% confidence interval (CI) 1.5–4.2, p = 0.0004). Discharge with a urinary catheter was more frequent after concurrent cases (35 vs 2%, p < 0.0001). Planned urogynecologic procedures were modified in 10% (n = 11) of cases. Conclusions Concurrent surgeries have an increased incidence of minor but not serious perioperative adverse events. One in ten planned urogynecologic procedures is either modified or abandoned during combined surgeries.