In this study, we compared the diagnosis rates of cervical cancer and carcinoma in situ between women who received Abnormal Pap notifications and participated in confirmatory tests within 6 months and those who did not. We also analyzed the differences based on age, economic status, and the level of urbanization. While there are big data studies on Pap smear participation rates, research specifically focusing on women with abnormal Pap results and their participation in confirmatory tests is scarce. Our study revealed that women in their 30s had the highest participation rates in confirmatory tests, and as age increased, the participation rates declined. This trend aligns consistently with Pap smear screening participation rates. (8)
The rate of diagnosis for cervical cancer increased with age among women who participated in confirmatory tests within 6 months. Even when tracking women who did not participate in confirmatory tests within 6 months for 5 years, the diagnosis rate for cervical cancer remained higher in older age groups. At the 5-year mark, the highest diagnosis rate was observed in the 70s. At the 5-year mark, the diagnosis rate was highest in the 70s; however, when compared to other age groups, the relative diagnosis rate was notably lower for those who underwent confirmatory tests within the 6 months prior to diagnosis.
In South Korea, unlike Western countries where the frequency of cervical cancer decreases after the age of 50 to 60 (9, 10), there is an increase in frequency with age.(11) On the other hand, for carcinoma in situ, unlike cervical cancer, the diagnosis rate decreases with age until the age of 60 and increases again at the age of 70. Both cervical cancer and carcinoma in situ had higher diagnosis rates in populations with lower economic levels and lower levels of urbanization.
Compared to women who underwent confirmatory tests within 6 months, the rate of diagnosis for Cervical cancer and carcinoma in situ was lower between 6 months and 5 years. However, when diagnosed, the relative proportion of diagnoses as cervical cancer, as opposed to carcinoma in situ, was higher. The diagnosis rate of cervical cancer was higher in the elderly, low-income groups, and areas with lower urbanization levels. Particularly in those aged 70 and above, there were more diagnoses of cervical cancer than cervical dysplasia. In cases diagnosed after 6 months, visits to the hospital were likely prompted by symptoms such as bleeding, rather than being asymptomatic, leading to a relatively higher proportion of diagnoses as cervical cancer. When cervical cancer was diagnosed, if it was discovered 6 months after the initial diagnosis, there might be a higher likelihood of the disease being at a more advanced stage than when discovered within the first 6 months, suggesting the need for further research in the future.
In this study, only 27.6% underwent confirmatory tests, a lower percentage compared to existing studies ranging from 43–64%. (12) These prior studies (2, 13, 14) often targeted a small number of patients from a single hospital, differing from the nationwide screenings in this research. When education pamphlets, phone calls, and letters were used to explain the necessity, the rate of receiving confirmatory tests increased to 64–72%, compared to a simple notification. Repetitive reminders increased the rate of confirmatory tests, emphasizing the effectiveness of phone-based reminders. However, implementing nationwide calls for all women with abnormal pap smears is not practically feasible. Selective approaches should be considered. Given the higher diagnosis rates of cervical cancer in low-income and elderly women in this study, encouraging repeated testing through mobile interventions when HSIL or higher abnormal pap smears are detected in these groups could be explored. Low-income individuals, smokers, and people with disabilities exhibit lower cervical cancer screening rates, and their confirmatory test rates drop when abnormal findings are present. Factors such as age and economic considerations (15–17), which contribute to not participating in cervical cancer screening, can overlap with reasons for avoiding confirmatory tests after receiving abnormal pap smear notifications, possibly driven by the fear associated with cancer (18).
The participation rate in confirmatory tests among the elderly was low. For many elderly women with physical disability, getting confirmatory test can be quite challenging. These women have reported difficulty in securing reliable transportation, locating clinics with specialized equipment, and entering a doctor’s office. While other studies (19, 20) conducted in Western countries have suggested a relationship between younger age and a decreased likelihood of follow-up after an abnormal Pap smear. There was no difference in confirmatory test participation rates based on economic factors, as South Korea's healthcare insurance system is well-established, indicating that cost is not a barrier. Factors such as occupation, hormone therapy, and smoking could influence participation of confirmatory test. Female employees in South Korea are more likely to undergo cervical cancer screening as employers may hold responsibility for regular check-ups.(17) However, it is not an obligation for employers to ensure additional tests for employees with abnormal findings during screenings. Women receiving hormone replacement therapy during menopause regularly visit gynecologists, increasing their likelihood of undergoing confirmatory tests. Smokers (17), known to disregard cervical cancer screening (21), might also exhibit a tendency to avoid confirmatory tests. These factors were not analyzed in this study.
This study has several limitations. Firstly, it relied on surgical codes and disease codes rather than actual pathological results, which may introduce some degree of discrepancy with real outcomes. Since cervical cancer was confirmed using disease codes, it is likely that adenocarcinoma and adenosquamous carcinoma were included in addition to squamous cell carcinoma from a histopathological perspective. Considering that squamous cell carcinoma constitutes the majority of cervical cancer cases, the impact of this omission is deemed minimal.(22) Following the ASCCP guidelines(23), colposcopy and uterine cervical punch biopsy can be performed even when Pap smear results are normal but HPV is positive(24) or when there are symptoms such as uterine bleeding. However, since this study is based on abnormal Pap results, such cases were excluded. Moreover, cases where hysterectomy was performed for conditions like uterine fibroids without undergoing cervical punch biopsy and were diagnosed with cervical dysplasia were also considered. Cases diagnosed with cervical cancer or cervical dysplasia based on disease codes, followed by confirmatory tests, were excluded from the study. Secondly, the study did not evaluate certain variables that could influence the implementation of confirmatory tests, such as the size of the hospital and the annual number of screenings. Thirdly, as the study is based on traditional Pap smear results, there might be differences in sensitivity and specificity compared to liquid-based cytology. Fourth, This study focused exclusively on squamous cell abnormalities, indicating a need for future research on glandular cell abnormalities.
As far as we know, this is the first study utilizing big data to analyze the factors influencing participation in confirmatory tests following abnormal Pap smear results and the diagnostic rates of cervical cancer and carcinoma in situ. Despite being a large-scale study, liquid-based cytology was excluded, and the analysis was uniformly based on traditional Pap smear. Abnormal Pap smear results should be subsequently linked to confirmatory tests. The elderly and those with lower socioeconomic status exhibit a higher diagnosis rate of cervical cancer in South Korea, emphasizing the importance of increasing their participation rates. Particularly in the elderly, the participation rate in confirmatory tests is low, necessitating focused management for this group. Cervical cancer is prevalent in the South-East Asian region. The incidence rates and participation in confirmatory tests for cervical cancer and carcinoma in situ in this region differ from those in Western countries. The cervical cancer elimination program advocated by the World Health Organization (WHO) should be tailored to the specific characteristics of each country.