Cam Nhung Bui

Effect of Pap smear screening on cervical cancer stage at diagnosis: results from the Korean National Cancer Screening Program

We aimed to determine the differences in stage at diagnosis of cervical cancer among Korean women according to screening history. Using linkage data from the Korean Central Cancer Registry and Korean National Cancer Screening Program (KNCSP), we included 18,388 women older than 30 years who were newly diagnosed with cervical cancer between 2013 and 2014 and examined their screening history. Between individuals, age group and socioeconomic status were matched to control for potential confounders. Significantly more cases of carcinoma in situ (CIS) were diagnosed in the ever-screened (71.77%) group than in the never-screened group (54.78%), while localized, regional, distant, and unknown stage were more frequent in the never-screened group. Women in the ever-screened group were most likely to be diagnosed with CIS than with invasive cervical cancer (adjusted odds ratio [aOR]=2.40; 95% confidence interval [CI]=2.18-2.65). The aOR for being diagnosed with CIS was highest among women who were screened 3 times or more (aOR=5.10; 95% CI=4.03-6.45). The ORs were highest for women screened within 24 months of diagnosis and tended to decrease with an increasing time since last screening (p-trend <0.01). The KNCSP for cervical cancer was found to be positively associated with diagnosis of cervical cancers at earlier stages among women aged 30 years or older. The benefit of screening according to time was highest for women screened within 24 months of diagnosis.

Trend analysis of process quality indicators for the Korean National Cervical Cancer Screening Program from 2005 to 2013

This study sought to examine changes in trends for quality indicators of the population-based Korean National Cancer Screening Program (KNCSP) for cervical cancer from years 2005 to 2013. Our study data were derived from the KNCSP database. Cervical cancer diagnosis information was ascertained through linkage with the Korean National Cancer Registry and the KNCSP database. Performance measures for cervical cancer screening were estimated, including participation rate, positive rate, crude detection rate (CDR), interval cancer rate (ICR), positive predictive value (PPV), sensitivity, and specificity. Joinpoint analysis was applied to calculate annual percentage changes (APCs) in all indicators according to socio-demographic factors. A significant increasing trend was noted in participation rates (APC=13.4%; 95% confidence interval [CI]=10.5, 16.4). PPV and specificity increased from years 2005 to 2009 and remained stable till 2013. An increasing trend was discovered in CDRs for cervical cancer in situ (APC=3.9%; 95% CI=1.0, 6.9), whereas a decreasing trend was observed in ICRs for invasive cervical cancer (APC=-2.5%; 95% CI=-4.5, -0.5). Medical Aid recipients and women older than 70 years showed the lowest participation rates, but higher CDRs and ICRs, compared to other groups. In general, most of the quality indicators for cervical cancer screening improved from 2005 to 2009 and remained stable to 2013. The KNCSP for cervical cancer in Korea has improved in terms of participation rate and accuracy of the screening test. These results may be attributed to the National Quality Improvement Program for KNCSP.