Impact of COVID-19 on Gynecological Cancer Incidence: A Large Cohort Study in Japan

Abstract Background: The influence of the coronavirus disease (COVID-19) pandemic on the number of newly diagnosed gynecological cancers has not been extensively investigated in Japan. This study aimed to determine the impact of COVID-19 on the incidence of gynecological cancer. Methods: Using the registry database of the Japanese Society of Obstetricians and Gynecologic Oncology, the distribution of the number of patients by clinical staging or tumor-node-metastasis (TNM) classifications before and during the COVID-19 pandemic was analyzed to compare the trends. The clinical staging classification of cervical cancer in Japan was based on the International Federation of Gynecology and Obstetrics (FIGO)-2008 from 2018 to 2020 and on the FIGO-2018 from 2021. Since FIGO-2018 classified N1 cases as stage IIIC, we focused on T classification without reference to the clinical staging (FIGO staging) of patients with cervical cancer in 2021. Results: The number of patients with endometrial cancer and malignant ovarian tumor of all clinical stages increased uniformly year-by-year while the number of patients with stage III cervical cancer increased sharply in 2021 owing to the adoption of the revised classification. On comparing cases with cervical cancer in 2020 and 2021, we found that T1 cases decreased and T2 and T3 cases increased in 2021 compared to those in 2020 (p=0.006). CIN3/AIS decreased in 2020 compared to in 2019 but increased again in 2021. The number of patients with cervical cancer decreased in most prefectures in 2020. Conclusion: The incidence of locally advanced cervical cancer increased during the COVID-19 pandemic.