RT Journal Article SR Electronic T1 243 Incidence of gynaecological cancer during the COVID-19 pandemic JF International Journal of Gynecologic Cancer JO Int J Gynecol Cancer FD BMJ Publishing Group Ltd SP A154 OP A155 DO 10.1136/ijgc-2021-ESGO.256 VO 31 IS Suppl 3 A1 Oymans, E A1 De Kroon, C A1 Bart, J A1 Van der Aa, M A1 Nijman, HW YR 2021 UL http://ijgc.bmj.com/content/31/Suppl_3/A154.3.abstract AB Introduction/Background*On the 11th of March 2020, the novel severe acute respiratory syndrome corona virus 2 (SARS-COV-2) was declared a pandemic. We studied the incidence and missed diagnoses in gynaecological oncology as a result of the impact of the COVID-19 pandemic and consequent lockdown and overcrowded hospitals in the Netherlands.Methodology We performed a retrospective cohort study using data from the Netherlands Cancer Registry (NCR) on women of 18 years and older diagnosed with invasive endometrial, ovarian, cervical or vulvar cancer in the period 2017-2020. The incidence was calculated for the period before the COVID-19 pandemic (mean number of the period 2017-2019) and compared with the incidence during the COVID-19 pandemic (2020) for each type of gynaecological cancer. The number of missed diagnoses was calculated as the difference in incidence between the period before and during the pandemic. Analyses were stratified for age, socioeconomical status (SES) and region.Result(s)*The incidence rate of gynaecological cancer was 57/100.000 (n = 4921) before and 53/100.000 (n = 4682) during the pandemic. Comparing the incidence of the two periods for the four types of cancer showed no significant difference (chi2 p=0.23). During the first wave of COVID-19 (March-June 2020), a clear decrease in incidence was visible for all four types of gynaecological cancer (figure 1). Subsequently, large increases in incidence were visible. A total of 299 diagnoses were missed during the pandemic (6.2% of the incidence of the period before COVID-19). The largest number of missed diagnoses was observed in ovarian cancer (n = 157, 10.9%), followed by cervical cancer (8.3%, n = 76), vulvar cancer (7.1%, n=31) and endometrial cancer (1.7%, n = 35). No significant differences in incidence were found for different age groups, SES and between regions.Abstract 243 Figure 1 Change in incidence over timeConclusion*In the Netherlands, a clear drop in incidence was visible for all four types of gynaecological cancers during the first wave, which was caught up in the second part of 2020 hence no significant difference with the period before COVID-19. The difference in incidence was not caught up completely, for 299 women walk around with missed diagnoses, which could result in higher stage disease or even worse.