Impact of Indoor Radon Exposure on Lung Cancer Incidence in Slovenia.

Indoor radon is an important risk factor for lung cancer, as 3-14% of lung cancer cases can be attributed to radon. The aim of our study was to estimate the impact of indoor radon exposure on lung cancer incidence over the last 40 years in Slovenia. We analyzed the distribution of lung cancer incidence across 212 municipalities and 6032 settlements in Slovenia. The standardized incidence ratios were smoothed with the Besag-York-Mollie model and fitted with the integrated nested Laplace approximation. A categorical explanatory variable, the risk of indoor radon exposure with low, moderate and high risk values, was added to the models. We also calculated the population attributable fraction. Between 2.8% and 6.5% of the lung cancer cases in Slovenia were attributable to indoor radon exposure, with values varying by time period. The relative risk of developing lung cancer was significantly higher among the residents of areas with a moderate and high risk of radon exposure. Indoor radon exposure is an important risk factor for lung cancer in Slovenia in areas with high natural radon radiation (especially in the southern and south-eastern parts of the country).

Impact of the COVID-19 epidemic on cancer burden and cancer care in Slovenia: a follow-up study.

BACKGROUND: In Slovenia, cancer care services were exempt from government decrees for COVID-19 containment. Nevertheless, cancer control can be impacted also by access to other health services and changes in health-seeking behaviour. In this follow up study, we explored changes in cancer burden and cancer care beyond the first months after the onset of the COVID-19 epidemic. MATERIALS AND METHODS: We analysed routinely collected data for the period January 2019 through July 2022 from three sources: (1) pathohistological and clinical practice cancer notifications from two major cancer centres in Ljubljana and Maribor (source: Slovenian Cancer Registry); (2) referrals issued for oncological services (source: e-referral system); and (3) outpatient appointments and diagnostic imaging performed (source: administrative data of the Institute of Oncology Ljubljana - IOL). Additionally, changes in certain clinical and demographic characteristics in patients diagnosed and treated during the epidemic were analysed using the Hospital-Based Cancer Registry of the IOL (period 2015-2021). RESULTS: After a drop in referrals to follow-up cancer appointments in April 2020, in June-August 2020, there was an increase in referrals, but it did not make-up for the drop in the first wave; the numbers in 2021 and 2022 were even lower than 2020. Referrals to first cancer care appointments and genetic testing and counselling increased in 2021 compared to 2019 and in 2022 increased further by more than a quarter. First and follow-up outpatient appointments and cancer diagnostic imaging at the IOL dropped after the onset of the epidemic in March 2020 but were as high as expected according to 2019 baseline already in 2021. Some deficits remain for follow-up outpatients' appointments in surgical and radiotherapy departments. There were more CT, MRI and PET scans performed during the COVID-19 period than before. New cancer diagnoses dropped in all observed years 2020, 2021 and until July 2022 by 6%, 3% and 8%, respectively, varying substantially by cancer type. The largest drop was seen in the 50-64 age group (almost 14% in 2020 and 16% in 2021), while for patients older than 80 years, the numbers were above expected according to the 2015-2019 average (4% in 2020, 8% in 2021). CONCLUSIONS: Our results show a varying effect of COVID-19 epidemic in Slovenia for different types of cancers and at different stages on the patient care pathway - it is probably a mixture of changes in health-seeking behaviour and systemic changes due to modifications in healthcare organisation on account of COVID-19. A general drop in new cancer cases reflects disruptions in the pre-diagnostic phase and could have profound long-term consequences on cancer burden indicators.

Prognostic factors and outcomes in women with breast cancer in Slovenia in relation to step-wise implementation of organized screening.

INTRODUCTION: The aim of organized breast cancer screening is early detection and reduction in mortality. Organized screening should promote equal access and reduce socio-economic inequalities. In Slovenia, organized breast cancer screening achieved complete coverage in 11-years' time. We explored whether step-wise implementation reflects in prognostic factors (earlier diagnosis and treatment) and survival of breast cancer patients in our population. METHODS: Using population-based cancer registry and screening registry data on breast cancer cases from 2008-2018, we compared stage distribution and mean time to surgical treatment in (A) women who underwent at least one mammography in the organized screening programme, women who received at least one invitation but did not undergo mammography and women who did not receive any screening invitation, and in (B) women who were invited to organized screening and those who were not. We also compared net survival by stage in different groups of women according to their screening programme status. RESULTS: Women who underwent at least one mammography in organized screening had lower disease stage at diagnosis. Time-to-treatment analysis showed mean time to surgery was shortest in women not included in organized screening (all stages = 36.0 days vs. 40.3 days in women included in organized screening). This could be due to quality assurance protocols with an obligatory multidisciplinary approach within the organized screening vs. standard treatment pathways which can vary in different (smaller) hospitals. Higher standard of care in screening is reflected in better survival in women included in organized screening (5-years net survival for regional stage: at least one mammography in the screening programme- 96%; invitation, but no mammography- 87.4%; no invitation or mammography in the screening programme- 82.6%). CONCLUSION: Our study, which is one of the first in central European countries, shows that introduction of organized screening has temporary effects on population cancer burden indicators already during roll-out period, which should therefore be as short as possible.

Cancer Patients' Survival According to Socioeconomic Environment in a High-Income Country with Universal Health Coverage.

Despite having an established systematic approach to population survival estimation in Slovenia, the influence of socioeconomic environment on cancer patients' survival has not yet been evaluated. Thus, the main aim of our study was to quantify the potential impact of socioeconomic environment on cancer patients' survival in our population in the 21st century. The net survival was calculated and stratified into quintiles of Slovenian version of the European Deprivation Index for all adult cancer patients diagnosed between 2004 and 2018 using the national cancer registry data. After accounting for basic demographic variables (age and gender), differences in stage at diagnosis, as well as the impact of the cancer treatment improvements over time, we found that cancer patients in Slovenia with lower socioeconomic status experience worse survival and have higher mortality. In particular, the odds of dying from oral, stomach, colorectal, liver, pancreatic, lung, breast, ovarian, corpus uteri, prostate, and bladder cancers, as well as for melanoma, leukemia, and non-Hodgkin lymphoma, are significantly higher in the socioeconomically most deprived group of patients compared to the most affluent group. The inequalities in cancer burden we found could help decision-makers to better understand the magnitude of this problem.

Trends in population-based cancer survival in Slovenia.

BACKGROUND: The aim of our study was to describe the survival of Slovenian cancer patients diagnosed in the last twenty years. An insight is given into the improvement made in different cancer types, population groups and prognostic factors. MATERIALS AND METHODS: The principal data source was the population-based Slovenian Cancer Registry. The survival analysis included patients diagnosed with cancer in twenty years period from 1997 to 2016, which has been divided into four consecutive five-year periods. In addition, the analysis was stratified by cancer type, gender, age and stage. The survival was estimated using net survival calculated by the Pohar-Perme method and the complete approach has been applied. RESULTS: The survival of Slovenian cancer patients has been increasing over time. During the 20 years observed, five-year net survival increased by 11 percentage points. Significantly higher growth was observed in men. Age and stage at diagnosis are still crucial for the survival of cancer patients. Five-year net survival is lowest in those over 75 years of age at diagnosis but has also improved by seven percentage points over the past 20 years. The five-year net survival of patients in the localized stage increased by ten percentage points over the 20 years under observation. Survival of patients in the distant stage has not been improving. In both sexes, survival for melanoma, colorectal and lung cancers have increased significantly over the last 20 years. Progress has also been made in the two most common gender specific cancers: breast cancer in women and prostate cancer in men. Still, the significant progress in prostate cancer is probably mostly due to lead-time bias as during the study period, Slovenia used indiscriminate PSA testing, which probably artificially prolonged survival. CONCLUSIONS: The survival of Slovenian cancer patients has been increasing over time, which gives us a basis and an incentive for future improvements. To monitor the effectiveness of managing the cancer epidemic, the cancer burden needs to be monitored also in the future, using quality data and scientifically justified methodological approaches. In this process a well organised population-based cancer registries should play a key role.

Screening Strategy Modification Based on Personalized Breast Cancer Risk Stratification and its Implementation in the National Guidelines - Pilot Study.

BACKGROUND: One of the most consistent models for estimating personalized breast cancer (BC) risk is the Tyrer-Cuzick algorithm that is incorporated into the International Breast Cancer Intervention Study (IBIS) software. Our main objective was to provide criteria for the classification of the Slovenian population, which has BC incidence below the European average, into risk groups, and to evaluate the integration of the criteria in Slovenian guidelines. Our main focus was on women age <50 with higher BC risk, since no organized BC screening is available for these women. METHODS: Slovenian age-specific BC risks were incorporated into IBIS software and threshold values of risk categories were determined. Risk categories were assigned according to the individual's ten-year risk for women aged 40 and older, and lifetime risk for women between 20 and 39. To test the software, we compared screening strategies with the use vs. no use of IBIS. RESULTS: Of the 197 women included in the study IBIS assigned 75.1% to the BC risk group, and the rest to the moderately increased risk. Without IBIS 80 women were offered mammographic and 33 ultrasound screening. In contrast, 28 instead of 80 would have been offered mammographic screening and there would have been no referrals for ultrasound if IBIS had been used. CONCLUSIONS: The Slovenian IBIS has been developed, tested and suggested for personalized breast cancer risk assessment. The implementation of the software with the consideration of Slovenian risk thresholds enables a more accurate and nationally unified assessment.

Breast cancer risk based on adapted IBIS prediction model in Slovenian women aged 40-49 years - could it be better?

Background The aim of the study was to assess the proportion of women that would be classified as at above-average risk of breast cancer based on the 10 year-risk prediction of the Slovenian breast cancer incidence rate (S-IBIS) program in two presumably above-average breast cancer risk populations in age group 40-49 years: (i) women referred for any reason to diagnostic breast centres and (ii) women who were diagnosed with breast cancer aged 40-49 years. Breast cancer is the commonest female cancer in Slovenia, with an incidence rate below European average. The Tyrer-Cuzick breast cancer risk assessment algorithm was recently adapted to S-IBIS. In Slovenia a tailored mammographic screening for women at above average risk in age group 40-49 years is considered in the future. S-IBIS is a possible tool to select population at above-average risk of breast cancer for tailored screening. Patients and methods In 357 healthy women aged 40-49 years referred for any reason to diagnostic breast centres and in 367 female breast cancer patients aged 40-49 years at time of diagnosis 10-years breast cancer risk was calculated using the S-IBIS software. The proportion of women classified as above-average risk of breast cancer was calculated for each subgroup of the study population. Results 48.7% of women in the Breast centre group and 39.2% of patients in the breast cancer group had above-average 10-year breast cancer risk. Positive family history of breast cancer was more prevalent in the Breast centre group (p < 0.05). Conclusions Inclusion of additional risk factors into the S-IBIS is warranted in the populations with breast cancer incidence below European average to reliably stratify women into breast cancer risk groups.

Impact of COVID-19 on cancer diagnosis and management in Slovenia - preliminary results.

Background The COVID-19 pandemic has disrupted the provision and use of healthcare services throughout the world. In Slovenia, an epidemic was officially declared between mid-March and mid-May 2020. Although all non-essential health care services were put on hold by government decree, oncological services were listed as an exception. Nevertheless, as cancer control depends also on other health services and additionally major changes in people's behaviour likely occurred, we aimed to analyse whether cancer diagnosis and management were affected during the COVID-19 epidemic in Slovenia. Methods We analysed routine data for the period November 2019 through May 2020 from three sources: (1) from the Slovenian Cancer Registry we analysed data on pathohistological and clinical practice cancer notifications from two major cancer centres in Ljubljana and Maribor; (2) from the e-referral system we analysed data on all referrals in Slovenia issued for oncological services, stratified by type of referral; and (3) from the administrative data of the Institute of Oncology Ljubljana we analysed data on outpatient visits by type as well as on diagnostic imaging performed. Results Compared to the November 2019 - February 2020 average, the decrease in April 2020 was about 43% and 29% for pathohistological and clinical cancer notifications; 33%, 46% and 85% for first, control and genetic counselling referrals; 19% (53%), 43% (72%) and 20% (21%) for first (and control) outpatient visits at the radiotherapy, surgery and medical oncology sectors at the Institute of Oncology Ljubljana, and 48%, 76%, and 42% for X-rays, mammograms and ultrasounds performed at the Institute, respectively. The number of CT and MRI scans performed was not affected. Conclusions Significant drops in first referrals for oncological services, first visits and imaging studies performed at the Institute, as well as cancer notifications in April 2020 point to a possibility of a delayed cancer diagnosis for some patients during the first surge of SARS-CoV-2 cases in Slovenia. The reasons for the delay cannot be ascertained with certainty and could be linked to health-seeking behaviour of the patients, the beliefs and practices of doctors and/ or the health system management during the epidemic. Drops in control referrals and control visits were expected and are most likely due to the Institute of Oncology Ljubljana postponing non-essential follow-ups through May 2020.

Socioeconomic inequalities in cancer incidence in Europe: a comprehensive review of population-based epidemiological studies.

Background Since the end of the previous century, there has not been a comprehensive review of European studies on socioeconomic inequality in cancer incidence. In view of recent advances in data source linkage and analytical methods, we aimed to update the knowledge base on associations between location-specific cancer incidence and individual or area-level measures of socio-economic status (SES) among European adults. Materials and methods We systematically searched three databases (PubMed, Scopus and Web of Science) for articles on cancer incidence and SES. Qualitative synthesis was performed on the 91 included English language studies, published between 2000 and 2019 in Europe, which focused on adults, relied on cancer registry data and reported on relative risk (RR) estimates. Results Adults with low SES have increased risk of head and neck, oesophagogastric, liver and gallbladder, pancreatic, lung, kidney, bladder, penile and cervical cancers (highest RRs for lung, head and neck, stomach and cervix). Conversely, high SES is linked with increased risk of thyroid, breast, prostate and skin cancers. Central nervous system and haematological cancers are not associated with SES. The positive gap in testicular cancer has narrowed, while colorectal cancer shows a varying pattern in different countries. Negative associations are generally stronger for men compared to women. Conclusions In Europe, cancers in almost all common locations are associated with SES and the inequalities can be explained to a varying degree by known life-style related factors, most notably smoking. Independent effects of many individual and area SES measures which capture different aspects of SES can also be observed.

Estimation of the Ecological Fallacy in the Geographical Analysis of the Association of Socio-Economic Deprivation and Cancer Incidence.

Ecological deprivation indices at the level of spatial units are often used to measure and monitor inequalities in health despite the possibility of ecological fallacy. For the purpose of this study, the European Deprivation Index (EDI) was used, which is based on Townsend theorization of relative deprivation. The Slovenian version of EDI (SI-EDI) at the aggregated level (SI-EDI-A) was calculated to the level of the national assembly polling stations. The SI-EDI was also calculated at the individual level (SI-EDI-I) by the method that represents a methodological innovation. The degree of ecological fallacy was estimated with the Receiver Operating Characteristics (ROC) curves. By calculating the area under the ROC curve, the ecological fallacy was evaluated numerically. Agreement between measuring deprivation with SI-EDI-A and SI-EDI-I was analysed by graphical methods and formal testing. The association of the socio-economic status and the cancer risk was analysed in all first cancer cases diagnosed in Slovenia at age 16 and older in the period 2011⁻2013. Analysis was done for each level separately, for SI-EDI-I and for SI-EDI-A. The Poisson regression model was implemented in both settings but adapted specifically for aggregated and individual data. The study clearly shows that ecological fallacy is unavoidable. However, although the association of cancer incidence and socio-economic deprivation at individual and aggregated levels was not the same for all cancer sites, the results were very similar for the majority of investigated cancer sites and especially for cancers associated with unhealthy lifestyles. The results confirm the assumptions from authors' previous research that using the level of the national assembly polling stations would be the acceptable way to aggregate data when explaining inequalities in health in Slovenia in ecological studies.

Slovenian Version of The European Deprivation Index at Municipal Level.

INTRODUCTION: Ecological deprivation indices belong to essential instruments for monitoring and understanding health inequalities. Our aim was to develop the SI-EDI, a newly derived European Deprivation Index for Slovenia. We intend to provide researchers and policy-makers in our country with a relevant tool for measuring and reducing the socioeconomic inequalities in health, and even at a broader level. METHODS: Data from the European survey on Income and Living Conditions and Slovenian national census for the year 2011 were used in the SI-EDI construction. The concept of relative deprivation was used where deprivation refers to unmet need(s), which is caused by lack of all kinds of resources, not only material. The SI-EDI was constructed for 210 Slovenian municipalities. Its geographical distribution was compared to the distribution of two existing deprivation scores previously applied in health inequality research in Slovenia. RESULTS: There were 36% of adults recognized as deprived in Slovenia in 2011. SI-EDI was calculated using 10 census variables that were associated with individual deprivation. A clear east-to-west gradient was detected with the most deprived municipalities in the eastern part of the country. The two existing deprivation scores correlate significantly with the SI-EDI. CONCLUSIONS: A new deprivation index, the SI-EDI, is grounded on the internationally established scientific concept, can be replicated over time and, crucially, provides an account of the socioeconomic and cultural particularities of the Slovenian population. The SI-EDI could be used by the stakeholders and the governmental and nongovernmental sectors in Slovenia, with the goal of better understanding health inequalities in Slovenia.

Cancer burden in slovenia with the time trends analysis.

BACKGROUND: The aim of our study was to describe cancer burden and time trends of all cancers combined, the most frequent as well as the rare cancers in Slovenia. PATIENTS AND METHODS: The principal data source was the population-based Cancer Registry of Republic of Slovenia. The cancer burden is presented by incidence and prevalence for the period 1950-2013 and by mortality for years 1985-2013. The time trends were characterized in terms of an average annual percent change estimated by the log-linear joinpoint regression. The Dyba-Hakulinen method was used for estimation of incidence in 2016 and the projections of cancer incidence for the year 2025 were calculated applying the Globocan projection software. RESULTS: In recent years, near 14,000 Slovenes were diagnosed with cancer per year and just over 6,000 died; more than 94,000 people who were ever diagnosed with cancer are currently living among us. The total burden of cancer is dominated by five most common cancer sites: skin (non-melanoma), colon and rectum, lung, breast and prostate, together representing almost 60% of all new cancer cases. On average the incidence of common cancers in Slovenia is increasing for 3.0% per year in last decade, but the incidence of rare cancers is stable. CONCLUSIONS: Because cancer occurs more among the elderly, and additionally more numerous post-war generation is entering this age group, it is expected that the burden of this disease will be growing further, even if the level of risk factors remains the same as today.

BRCA2 gene mutations in Slovenian male breast cancer patients.

Male breast cancer (MBC) is a rare disease, comprising less than 1% of breast cancer patients in Slovenia. Some inherited cases are due to the mutations of BRCA1 or BRCA2 genes. There is no information available about the frequency of BRCA gene mutations in Slovenian MBC population. The purpose of this study was to characterize BRCA germline mutations in Slovenian MBC patients. Forty-one patients who were diagnosed with breast cancer at the Institute of Oncology Ljubljana between 1970 and 2006 were proposed to take part in this study. Of them, 27 agreed to follow a genetic counseling session and 25 patients agreed to provide a blood sample for genetic testing. The BRCA1 and BRCA2 genes from the MBC patients were screened for four highly recurrent mutations in the Slovenian population. When an additional breast cancer case or an ovarian cancer was present in the family, a more extended analysis was performed. No BRCA1 mutations were found. A BRCA2 gene mutation was identified in four MBC patients. Three of them carried the Slovenian founder mutation IVS16-2A>G. All four mutations were confined to the patients with a family history of breast cancer. Among the MBC patients with a family history of breast cancer in the first- or second-degree relatives, the frequency of BRCA2 gene mutation was 50%. The median age of the patients with a BRCA2 gene mutation was 60 years, not significantly different from those without a mutation. The BRCA2 mutations were diagnosed in 16% of our MBC patients.