OBJECTIVE: To investigate the infection characteristics in ovarian cancer (OC) patients with concomitant vaginitis and identify the risk factors for the patients. METHODS: A retrospective analysis was conducted on the clinical data from 100 OC patients treated at the Yiwu Central Hospital from July 2019 to July 2024. Patients were assigned to the infection group (n=34) or non-infection group (n=66) based on the presence of vaginitis. Outcome measures included the infection rate and vaginal microbial characteristics of vaginitis, serum HE4 level, and concentrations of interleukin (IL)-4, IL-6, and IL-10 in vaginal secretions. Multivariate logistic regression analysis was performed to determine the influencing factors for vaginal infection in OC patients. Receiver operator characteristic (ROC) curve analysis was conducted to assess the predictive performance of independent risk factors for the occurrence of vaginal infections in OC patients. RESULTS: Among the 100 OC patients, 34 cases (34%) had concomitant vaginitis. Among the 34 patients, the composition ratio of infection types from most to least common was as follows: 10 patients with vulvovaginal candidiasis (29.41%), 8 patients with bacterial vaginosis (23.53%), 7 patients with microbial imbalance (20.59%), 5 patients with mixed infections (14.71%), 3 patients with aerobic vaginitis (8.82%), and 1 patient with trichomonal vaginitis (2.94%). The two groups did not differ notably in HE4 levels (P=0.2366). However, IL-4, IL-6, and IL-10 levels were notably higher in the infection group compared to the non-infection one (P<
0.0002). Multivariate logistic regression analysis identified education level, sexual frequency, self-vaginal douching, and history of vaginitis as independent factors influencing vaginal infection in OC patients, and the joint prediction of the vaginal infections with independent factors had an area under curve of 0.858, presenting better performance than a single factor. CONCLUSION: Vulvovaginal candidiasis is the predominant type of vaginitis in OC patients, followed by BV. Education level, sexual frequency, self-vaginal douching, and a history of vaginitis are independent factors influencing vaginal infection in OC patients.