Factors associated with advanced-stage diagnosis of cervical cancer in Estonia: a population-based study

OBJECTIVES

Cervical cancer (CC) remains a crucial public health issue in Estonia, with high incidence and late diagnosis. The aim of this study was to examine time trends of stage-specific CC incidence in Estonia and factors associated with advanced-stage diagnosis of CC.

STUDY DESIGN

This was a nationwide population-based retrospective study.

METHODS

Data on CC cases diagnosed in Estonia in 2007-2018 were obtained from the Estonian Cancer Registry, including tumour, nodes, metastases stage at diagnosis. Sociodemographic data were obtained from the Population Registry. To estimate the risk of advanced-stage diagnosis (stages II-IV vs stage I) associated with sociodemographic factors, Poisson regression with robust variance was used to calculate univariate and multivariate prevalence ratios (PR) with 95% confidence intervals (CIs). Time trends of stage-specific CC incidence for 2005-2019 were examined with joinpoint analysis.

RESULTS

Incidence of stage I CC showed a significant decline of 4.9% per year since 2007, whereas no change was seen for other stages. Of the 2046 women diagnosed in 2007-2018, 1137 (55.6%) were diagnosed at an advanced stage; this proportion increased from 51% in 2007-2009 to 58% in 2015-2018 (P = 0.004). Multivariate regression analysis showed that advanced-stage diagnosis was associated with age (PR 2.16, 95% CI 1.87-2.49 for women aged ≥75 years compared with those aged 30-44 years), educational level (PR 1.32, 95% CI 1.15-1.51 for women with basic/primary education compared to university education) and marital status (PR 1.14, 95% CI 1.01-1.29 for single women compared to married/cohabiting women). No associations were observed by region of residence or nationality.

CONCLUSIONS

To reduce CC mortality, it is crucial to improve prevention and early diagnosis of CC in Estonia through human papillomavirus vaccination and effective and quality-assured screening particularly targeting high-risk groups as well as encouraging symptom awareness and regular check-ups among older women.

Global survival trends for brain tumors, by histology: analysis of individual records for 556,237 adults diagnosed in 59 countries during 2000-2014 (CONCORD-3)

BACKGROUND

Survival is a key metric of the effectiveness of a health system in managing cancer. We set out to provide a comprehensive examination of worldwide variation and trends in survival from brain tumors in adults, by histology.

METHODS

We analyzed individual data for adults (15-99 years) diagnosed with a brain tumor (ICD-O-3 topography code C71) during 2000-2014, regardless of tumor behavior. Data underwent a 3-phase quality control as part of CONCORD-3. We estimated net survival for 11 histology groups, using the unbiased nonparametric Pohar Perme estimator.

RESULTS

The study included 556,237 adults. In 2010-2014, the global range in age-standardized 5-year net survival for the most common sub-types was broad: in the range 20%-38% for diffuse and anaplastic astrocytoma, from 4% to 17% for glioblastoma, and between 32% and 69% for oligodendroglioma. For patients with glioblastoma, the largest gains in survival occurred between 2000-2004 and 2005-2009. These improvements were more noticeable among adults diagnosed aged 40-70 years than among younger adults.

CONCLUSIONS

To the best of our knowledge, this study provides the largest account to date of global trends in population-based survival for brain tumors by histology in adults. We have highlighted remarkable gains in 5-year survival from glioblastoma since 2005, providing large-scale empirical evidence on the uptake of chemoradiation at population level. Worldwide, survival improvements have been extensive, but some countries still lag behind. Our findings may help clinicians involved in national and international tumor pathway boards to promote initiatives aimed at more extensive implementation of clinical guidelines.

HPV self-sampling as an additional option in cervical cancer screening: a pilot study in Estonia

Background

Cervical cancer incidence and mortality rates remain high in Estonia and participation in organized cervical cancer screening program is low. The aim of this pilot study was to estimate the impact of offering an HPV self-sampling option on screening uptake.

Methods

A randomized intervention study was conducted within Estonian organized cervical cancer screening program in 2021. Among target group women who had not participated in screening by August 2021, 26,000 women were randomly selected and allocated to two equally sized intervention arms offering a choice between attending a clinic or taking a self-sample. The opt-out group received a Qvintip sampler by regular mail to home address, the opt-in group received by e-mail a link to order the sampler from a web-site. A control group of 32,000 women received the usual reminder to attend screening at a clinic. Participation rates were calculated and data on user experience were collected with a questionnaire.

Results

Significant difference in participation rates was observed between opt-out (41%) (among them 20% chose self-sampling, 21% chose clinic attendance), opt-in (34%) (8% self-sampling, 26% clinic) and control group (28%). Intervention arms showed higher screening uptake in all age-groups and regions, but the largest effect was seen at ages 60 and 65 years and in regions showing the lowest screening participation rates. Among self-sampling users, 99% agreed that self-sampling was easy and only 3% prefer testing at a clinic.

Conclusions

Offering women a choice between HPV self-sampling or attending a clinic significantly increased cervical cancer screening uptake. Sending an HPV self-sampling kit to home address was the most effective approach. Majority of women who chose HPV self-sampling want to use this option in the future. HPV self-sampling should be integrated in the cervical cancer screening program in Estonia.

Key messages

HPV self-sampling among cervical cancer screening nonattenders: a feasibility study in Estonia

Background

Organized cervical cancer screening in Estonia was started in 2006, but it has not been effective, partly due to low coverage. In 2021, primary HPV screening was implemented. HPV self-sampling has been shown to be effective in increasing screening uptake. This is the first study in Estonia addressing the feasibility of HPV self-sampling and the acceptance of this method among long-term screening nonattenders.

Methods

A randomized intervention study was conducted in 2020. Women born between 1958-1983 without a Pap-smear in 2013-2019 were included in the study population. Altogether 12 000 women were randomly allocated to three equally sized study groups. Opt-out group received a Qvintip sampling device by regular mail. Two opt-in groups received an e-mail invitation to order a self-sampler from a website, one received Qvintip and the other Evalyn Brush. Data on user experience was collected with a questionnaire. Participantś background characteristics were obtained from the Population Register. The effect of covariates on participation rate was estimated with multivariate Poisson regression with a robust error variance and risk ratios (RR) were calculated.

Results

Overall participation rate was 17%, but significant differences were observed between opt-out (27%) and opt-in groups (11%). Compared to opt-out group, adjusted RRs for Qvintip and Evalyn Brush opt-in groups were 0.39 (95% CI 0.35-0.42) and 0.42 (95% CI 0.38-0.47), respectively. Participation was significantly associated with region, citizenship, and education. Self-sampling was well accepted: 98% agreed that it was easy and convenient; 88% prefer it as a screening method in future.

Conclusions

The study showed the feasibility and high acceptance of HPV self-sampling among long-term screening nonattenders in Estonia. As a next step, self-sampling will be piloted in organized screening program to identify optimal dissemination strategy.

Key messages

HPV self-sampling in Estonia is feasible, well accepted and has the potential for improving screening uptake among hard-to-reach women. Self-sampling strategy will be further tested within cervical cancer screening program.

Pap-smear and cervical cancer in Estonia: a population-based case-control study

Backround

Studies have shown the ineffectiveness of Estonian cervical cancer (CC) screening programme. To examine the reasons for high CC incidence in Estonia, a study was conducted, linking individual Pap-smear history to CC incidence.

Methods

In this population-based case-control study, cases were women aged ≥25 years with an in situ/invasive CC diagnosed in Estonia in 2011-2017, derived from cancer registry. Three controls per case were randomly selected from population registry using a density sampling scheme. Exposure was defined as no Pap-smears during seven years prior to diagnosis or index date compared to at least one smear. Multivariate logistic regression was used to calculate odds ratios (OR) with 95% confidence intervals (CI). Age, place of residence, citizenship, education, marital status and interruption in health insurance were also analysed. The analysis was done separately in screening age group (35-60 years).

Results

Among 1439 cases and 4317 controls, the proportion of women with no Pap-smears was 53% and 35%, respectively. In multivariate analysis, women with no Pap-smears were at a higher risk for CC (OR = 2.42; 95% CI: 1.97-2.97). In screening age group, the impact of no Pap-smears was stronger (OR = 2.62; 95% CI: 2.12-3.24). CC risk decreased with age, was two to three times higher in other regions compared to Northern Estonia; was higher for lower-educated women; and for divorced/widowed women compared to married women. Interruption in health insurance caused a 25% increase in risk. However in screening age group, women with no Pap-smears and an interruption in health insurance experienced a four-fold increase in CC risk.

Conclusions

The study confirmed the importance of screening in preventing CC, also revealing the independent effect of several social factors on CC risk. To reduce CC incidence in Estonia, immediate efforts are necessary to increase the effectiveness of screening, particularly among high-risk and hard-to-reach women.

Key messages

This case-control study of cervical cancer in Estonia identified high-risk groups: women with no Pap-smears, interruptions in health insurance, low education, and living outside the capital city area. Reduction in cervical cancer incidence in Estonia can be achieved through more effective screening and communication, tailored to the needs of different population groups, mainly high-risk women.

Evolution of severe trauma in Estonia comparing early versus established independence of the state

PURPOSE

Trauma mechanisms and patterns of severe injuries during the Estonian independence have not been evaluated. The aim of the study was to compare the incidence and outcomes of severe injuries between time periods of early independence from the Soviet Union and the present time.

METHODS

After the ethics review board approval, all adult trauma admissions to major trauma facilities in 1993-1994 and 2013-2014 with Injury Severity Score >15 were identified. Data collection included demographics, injury severity variables, interventions, and in-hospital outcomes. Primary outcome was in-hospital mortality. Secondary outcomes included incidence of penetrating trauma, hospital length of stay (HLOS), and in-hospital complications. Primary outcome difference comparing the two time segments was determined using logistic regression analysis.

RESULTS

A total of 1064 patients were included, 593 and 471 from 1993-1994 to 2013-2014, respectively. Incidence of penetrating trauma during 1993-1994 was 11.1 % and in 2013-2014 at 6.4 % (p = 0.007). Gunshot injuries constituted 62.1 and 23.3 % of all penetrating trauma in 1993-1994 and 2013-2014, respectively (p < 0.001). The overall mean HLOS was 15.5 ± 19.8 days and did not differ between the periods. The rate of adjusted complications showed a trend for a decreased incidence (adj. p = 0.064). Adjusted mortality rate was 50.3 and 16.4 % during 1993-1994 and 2013-2014, respectively (adj. OR 7.01; 95 % CI 4.69-10.47; p < 0.001).

CONCLUSIONS

Effective law enforcement, gun control, evolution of trauma system, and reduction of interpersonal violence have all contributed to a significant decrease in penetrating trauma incidence and all-cause adjusted mortality during the 20 years of Estonian independence.

Suicides among cancer patients in Estonia: a population-based study

The objective of this study was to determine the suicide risk among cancer patients in Estonia. This risk was examined in a cohort of 65,419 persons diagnosed with cancer in 1983-1998. Standardised mortality ratios (SMR) were calculated using the suicide rates of the population of Estonia as a reference. During 192,078 person-years of follow-up between 1983 and 2000, 197 suicides occurred in the cohort. An increased suicide risk was found for men (SMR=1.73; 95% Confidence Interval (CI) 1.45-2.01), but not for women (SMR=0.50; 95% CI 0.37-0.66). Men had the highest risk 90-179 days following their diagnosis (SMR=4.27; 95% CI 2.81-6.21). During this time interval, among men, the risk was more pronounced for cancers of the oesophagus (SMR=35.63; 95% CI 9.71-91.22) and pancreas (SMR=14.53; 95% CI 1.76-52.50). This study provides further evidence that cancer is a risk factor for suicide, at least in men.

Epidemiological data sources in Estonia: a survey of registries and databases

BACKGROUND

Central and Eastern European countries offer opportunities for studying the health effects of historical and present exposures, as well as the transition to a market economy. A prerequisite for research is the availability of good-quality information. This study was undertaken to describe sources of individual data that are available for epidemiological research in Estonia. Particular attention was paid to the methods of operation of health registries.

METHODS

Information was collected during site visits, interviews with registry personnel and from published reports. For health registries, information was specifically requested on data collection, scope of recorded data, quality control, electronic linkage capability and use of data in research.

RESULTS

The authors describe 35 data sources containing individual information on vital status, mortality, morbidity, natality and women's health, health and health care, and occupation. The most important health registries are the cancer registry, with data from 1968, and the medical birth registry, with data from 1992. Computerised cause-of-death information is available from 1983. Electronic linkage can be done with most of the data sources, the main matching variable being the eleven-digit personal identification number. Factors potentially affecting data-quality in health registries are undefined legal basis, scarcity of funding and staff, poor acknowledgement of problems, and rare scientific use of registry

DISCUSSION

Various data sources are available for epidemiological research in Estonia. Thus far, collected data have largely been an under-used scientific resource. In health registries, more attention should be paid to quality control and continuous involvement of researchers.

Wood dust exposure and cancer incidence: a retrospective cohort study of furniture workers in Estonia

BACKGROUND

Occupational wood dust exposure is associated with increased risk of sinonasal cancer in men. However, little is known whether it is associated with sinonasal cancer in women or with malignancies of other sites.

METHODS

In a retrospective cohort study of furniture workers, cancer incidence in 3723 men and 3063 women between 1968 and 1995 was compared to the incidence in the general population of Estonia. Cancer risks were analyzed by employment duration and occupation.

RESULTS

The standardized incidence ratio (SIR) for all cancers did not differ significantly from one. Two men and one woman had sinonasal cancer (expected 1.07 and 0.53, respectively). Significantly increased risk of colon cancer was seen in the cohort (SIR 1.65, 95% confidence interval (CI) 1.22-2.17). Subjects employed for 10 years and over had significant excess of colon cancer (SIR 2.29, 95% CI 1.28-3.77) and rectal cancer (SIR 2.10, 95% CI 1.05-3.76) in the analysis by employment duration using exposure with a latency of 20 years. The nonsignificant excess of pharyngeal cancer in men (SIR 1.82) and lung cancer in women (SIR 1.43) was restricted to short-term workers.

CONCLUSIONS

This study found an excess of colon and rectal cancer in furniture workers. There was no increase in total cancer risk.

Feasibility of cohort studies in Estonia

OBJECTIVES

To describe the methodology and feasibility of follow up for vital status in retrospective cohort studies in Estonia.

METHODS

A cohort of 7412 workers who had been employed at two factories in Tallinn between 1946 and 1988 was followed up for vital status from the date of first employment until death, emigration, or the end of the study, 31 December 1995, whichever occurred first. The cohort was electronically linked with the National Population Registry of Estonia that was created in 1992 and includes personal identification numbers of Estonian citizens and residents, and the Mortality Database that contains information from death certificates issued in 1983-95. A manual search was carried out on several non-computerised population data sources and archives.

RESULTS

By 31 December 1995, the vital status of 6780 (91.5%) subjects could be traced (4495 (60.6%) subjects were alive, 1993 (26.9%) had died, and 292 (3.9%) had emigrated). Analysis by calendar period of leaving work showed that the proportion of subjects traced was lowest in the group of workers who had left work between 1946 and 1955 (58.4%), especially those whose age at leaving work was < 30 (53.2%) or > 60 years (42.3%). Among subjects who left work in 1956-65, 1966-75, and 1976-88, the follow up rate was 84.7%, 94.6%, and 98.2%, respectively.

CONCLUSIONS

The findings, which are especially important for occupational epidemiology, confirm the feasibility of conducting retrospective cohort studies in Estonia. Most of the issues discussed in the paper apply to other former Soviet countries.