Organized cervical cancer screening program for women aged 30 or over using Pap Smear has been launched in Korea since 1999. However, there is limited evidence showing the effectiveness of this nationwide screening program in reducing cervical cancer mortality. In this study, we aim to examine cervical cancer mortality among screened and non-screened women who participated in the Korean National Cancer Screening Program (KNCSP) from 2002 to 2003.
We conducted a prospective cohort study of women aged 30-79 years invited to the KNCSP between 2002 - 2003 and followed up to 2015 for deaths from cervical cancer and other causes. Women with incomplete ID, diagnosed with cervical cancer before entering the cohort, or older than 79 years were excluded. Finally, a total of 8,262,267 women aged 30-79 were included, and their cervical cancer screening exposure, cancer incidence, and death information were collected from the KNCSP database, National Cancer Registry, and death certificate from Statistics Korea. There were 6,615,614 women in the screen group (mean person-year: 9.74) and 5,814,989 women in the non-screen group (mean person-year: 8.33). Incidence rate ratio (IRR) and Mortality rate ratio (MRR) were used to compare between screen and non-screen cohorts using Poisson regression model. The MRRs and IRRs were adjusted for age at inclusion in the cohort, insurance type, and self-selection bias.
The crude mortality rate was 3.49 and 8.77 per 100,000 women-years for screen and non-screen group, respectively. MRR for cervical cancer was 0.46 (95% confidence interval (CI): 0.44-0.48). After adjusting for self-selection bias, it was estimated that there was 36.11% of mortality reduction in screen group compared to non-screen group. Also, IRR of invasive cancer in screen group was 0.74 (95% CI: 0.72-0.76) compared to non-screen group. However, there was no significant reduction in the total number of invasive cervical cancer and cervical cancer in situ incidence rate (IRR: 0.98; 95%CI: 0.98 (0.96-1.00)).
We found that after 13 years of follow-up, 36.11% of cervical cancer mortality reduction was observed among women who attended the Korean National Cervical Cancer Screening Program.
Kui Son Choi.
National Cancer Center, Korea (Grant number: 1610401) and International Cooperation & Education Program (NCCRI·NCCI 52210-52211,2019) of National Cancer Center, Korea.
All authors have declared no conflicts of interest.