Patterns of survival and surgical treatment in lung cancer patients in Estonia by histologic type and stage, 1996-2016.

Background: Lung cancer (LC) remains the most frequent cause of cancer death worldwide. We aimed to examine long-term trends in LC survival in Estonia by age, gender, histologic type and stage, with specific focus on surgical treatment.Material and methods: Data on all incident cases of LC diagnosed from 1996 to 2016 were obtained from the Estonian Cancer Registry. Logistic regression was used to examine receipt of surgical treatment in localized LC. Relative survival ratios (RSR) were calculated, and excess hazard ratios (EHR) of death were estimated by stage with gender, age, histology and period of diagnosis as independent variables.Results: Among the total of 16,423 cases, squamous cell carcinoma remained the most common histologic type. The odds of receiving surgical treatment in localized LC increased significantly over time and were associated with age, gender and histologic type. Overall, the age-standardized 5-year RSR improved significantly from 10% in 1996-2002 to 16% in 2010-2016 (from 8% to 15% in men and from 15% to 20% in women). Larger survival gain was seen in younger patients, for non-small cell LC subtypes, and for surgically treated patients. For localized disease, the 5-year RSR increased by more than 20 percentage units, reaching 50% in men and 69% in women. For all stages, the adjusted EHR of death was significantly associated with age, histologic type and period of diagnosis.Conclusions: We observed a substantial improvement of relative survival, with considerable variations across patient groups. After adjustment for age, gender and histology, a significant survival increase over time was seen for all stages. The considerable survival gain observed for localized LC can largely be attributed to rapidly growing proportion of surgically treated patients. Further investigation of LC management practices, particularly the use of non-surgical treatment options is warranted.

Increasing kidney cancer incidence and survival in Estonia: role of age and stage.

BACKGROUND: Kidney cancer rates in Estonia are high. The study aimed to examine long-term trends in kidney cancer incidence, mortality and survival in Estonia, with special focus on age, birth cohorts, morphology and TNM stage. MATERIAL AND METHODS: Estonian Cancer Registry provided data on all incident cases of kidney cancer (ICD-10 C64), diagnosed in adults (age ≥15 years) in Estonia during 1995 - 2014. Relative survival ratios (RSR) were calculated and excess hazard ratios of dying were estimated with gender, age, period of diagnosis and TNM stage as independent variables. Joinpoint regression modeling was used to calculate estimated annual percentage change for incidence (1970-2014) and mortality (1995-2016) trends. Age-specific incidence rates were presented by birth cohort and period of diagnosis. RESULTS: Incidence increased significantly in both sexes, with the steepest rise seen for localized cancer. Cohort effects were pronounced particularly in men, while period effects were seen from the mid-1980s to mid-1990s in both sexes. Age-standardized five-year RSR for total kidney cancer increased by 13 percentage units (from 53% to 65%) over the study period; the increase was larger for renal cell carcinoma (from 63% to 78%). Survival increases of about five percentage units were seen for stages I/II and III. Age and gender were not associated with excess risk of dying from renal cell carcinoma after adjusting for stage. CONCLUSION: Estonia is currently among countries with the highest incidence of kidney cancer. The results suggest a combined effect of changing risk profiles in successive birth cohorts and increasing diagnostic activity around 1990. Large survival increase can mostly be attributed to earlier detection, but improved diagnosis and treatment have probably influenced stage-specific survival. High proportion of tumors with unspecified morphology and those with unknown stage among the elderly warrants further investigation of diagnostic and treatment practices.

Subsite- and stage-specific colorectal cancer trends in Estonia prior to implementation of screening.

BACKGROUND: The occurrence of colorectal cancer (CRC) in Estonia has been characterised by increasing incidence, low survival and no screening. The study aimed to examine long-term incidence and survival trends of CRC in Estonia with specific focus on subsite and stage. METHODS: We analysed CRC incidence and relative survival using Estonian Cancer Registry data on all cases of colorectal cancer (ICD-10 C18-21) diagnosed in 1995-2014. TNM classification was used to categorise stage. RESULTS: Age-standardized incidence of colon cancer increased both in men and women at a rate of approximately 1% per year. Significant increase was seen for right-sided tumours, but not for left-sided tumours. Rectal cancer incidence increased significantly only in men and anal cancer incidence only in women. Age-standardized five-year relative survival for colon cancer increased from 50% in 1995-1999 to 59% in 2010-2014; for rectal cancer, from 38% to 56%. Colon cancer survival improved significantly for left-sided tumours (from 51% to 62%) and stage IV disease (from 6% to 15%). For rectal cancer, significant survival gain was seen for stage II (from 58% to 75%), stage III (from 34% to 70%) and stage IV (from 1% to 12%). CONCLUSION: In the pre-screening era in Estonia, increase in colon cancer incidence was limited to right-sided tumours. Large stage-specific survival gain, particularly for rectal cancer, was probably due to better staging and advances in multimodality treatment. Nonetheless, more than one quarter of new CRC cases are diagnosed at stage IV, emphasising the need for an efficient screening program.

Divergent trends in lung cancer incidence by gender, age and histological type in Estonia: a nationwide population-based study.

BACKGROUND: Lung cancer (LC) is the leading cause of cancer deaths in men and the second most frequent cause of cancer deaths in women in Estonia. The study aimed to analyze time trends in LC incidence and mortality in Estonia over the 30-year period, which included major social, economic and health care transition. The results are discussed in the context of changes in tobacco control and smoking prevalence. Long-term predictions of incidence and mortality are provided. METHODS: Data for calculating the incidence and mortality rates in 1985-2014 were obtained from the nationwide population-based Estonian Cancer Registry and the Causes of Death Registry. Joinpoint regression was used to analyze trends and estimate annual percentage change (APC) with 95% confidence interval (CI). Nordpred model was used to project future incidence and mortality trends for 2015-2034. RESULTS: Incidence peaked among men in 1991 and decreased thereafter (APC: -1.5, 95% CI: -1.8; -1.3). A decline was seen for all age groups, except age ≥ 75 years, and for all histological types, except adenocarcinoma and large cell carcinoma. Incidence among women increased overall (APC: 1.6, 95% CI: 1.1; 2.0) and in all age groups and histological types, except small cell carcinoma. Age-standardized incidence rate (world) per 100,000 was 54.2 in men and 12.9 in women in 2014. Changes in mortality closely followed those in incidence. According to our predictions, the age-standardized incidence and mortality rates will continue to decrease in men and reach a plateau in women. CONCLUSIONS: The study revealed divergent LC trends by gender, age and histological type, which were generally consistent with main international findings. Growing public awareness and stricter tobacco control have stimulated overall favorable changes in men, but not yet in women. Large increase in incidence was observed for adenocarcinoma, which in men showed a trend opposite to the overall decline. LC will remain a serious public health issue in Estonia due to a high number of cases during the next decades, related to aging population, and previous and current smoking patterns. National tobacco control policy in Estonia should prioritize preventing smoking initiation and promoting smoking cessation, particularly among women.

The impact of under-reporting of cases on the estimates of childhood cancer incidence and survival in Estonia.

About 35 new childhood cancer cases are diagnosed in Estonia (population 1.3 million in 2011) every year. Despite continuous improvements in the healthcare system and available cancer treatment options, the survival rates for childhood cancers have appeared to remain lower than the European average. These observations and the accompanying decrease in incidence led us to hypothesize that some nonfatal cases might be missing from the Estonian Cancer Registry (ECR). The aim of this study was to evaluate the completeness of reporting of childhood cancer cases to the ECR and its impact on the estimates of cancer incidence and survival. All cases of benign and malignant tumours, diagnosed in 2000-2011 among children aged 0-17 years and eligible for registration in the ECR, were included in the study. Completeness of reporting was evaluated for cases aged 0-17 years, and incidence and survival were analysed for cases aged 0-14 for international comparisons. The total number of new cancer cases increased from 459 to 515. Overall completeness of case ascertainment was estimated to be 89.5%. After adding the missing cases, the overall incidence rate increased from 12.9 to 14.9/100 000 (from 3.4 to 4.7 for leukaemias). The 2010-2014 period estimate of the 5-year survival increased from 70 to 76% for all sites combined and from 71 to 82% for leukaemias. In conclusion, the under-reporting of nonfatal childhood cancer cases to the ECR had an important impact on incidence and survival rates, causing a considerable underestimation of both.

Recent changes in breast cancer incidence and mortality in Estonia: Transition to the west.

Background The aim of this study was to examine breast cancer (BC) incidence and mortality trends in Estonia during recent decades and to compare the pattern of these trends with other selected European countries and regions. We attempt to explain the findings in relation to changes in Estonian society and healthcare system. Methods BC incidence (1985-2012) and mortality (1985-2013) data for Estonia were obtained from the Estonian Cancer Registry and Statistics Estonia. Data for selected European countries were obtained from the EUREG database. Joinpoint regression was used to analyze age-standardized rates in Estonia by age. For international comparison of incidence and mortality rates, we used scatterplot with 95% confidence ellipses and the mortality to incidence ratio. Results The overall BC incidence continues to increase in Estonia, while mortality has been in decline since 2000. Both incidence and mortality trends varied considerably across age groups. Among women aged 60 years and older, BC incidence increased at a rate of nearly 3% per year. Significant decrease in mortality was seen only among women aged 50-59 years. Comparison of scatterplots between countries and regions revealed two clusters in Europe separated along the incidence axis. The correlation between incidence and mortality in Estonia changed its direction in the mid-1990s. Conclusion In recent years, the dynamics of BC burden in Estonia has transitioned towards the high incidence-low mortality type model, which is characteristic to Western, Northern and Southern Europe. Although overall BC incidence is much lower in Estonia than in more affluent European countries, mortality from BC is still relatively high, particularly among elderly women.

Age-specific cancer survival in Estonia: recent trends and data quality.

BACKGROUND: A number of population-based studies have demonstrated lower cancer survival in elderly patients than among middle-aged or younger patients. Also, data quality in cancer registries has been shown to be associated with age. The objective of this study was to examine the recent age-specific cancer survival trends and age-specific quality of cancer data in Estonia. METHODS: Using Estonian Cancer Registry data, we calculated relative survival ratios (RSRs) for eight common cancers in Estonia in 1995-1999 (cohort method) and 2005-2009 (period method) for four major age groups (15-54, 55-64, 65-74, and 75-84 years at diagnosis). The main data quality indicators were calculated, and the age-specific effect of missing death certificate initiated (DCI) cases on survival was estimated comparing 5-year RSRs computed from the complete data set with those from data set without DCI cases. RESULTS: We observed overall rise in 5-year RSR for all eight cancers over the study period, with a considerable variation by age, with the lowest survival among the oldest patients. The widest age gradient in 5-year RSR was seen for bladder cancer (20% units in 2005-2009), followed by cancers of lung (16% units), kidney (15% units), breast and prostate (13% units), stomach and rectum (11% units), and colon (5% units). All data quality indicators, including proportion of cases with unknown stage showed a similar age-related pattern with the lowest quality in the oldest age group. The effect of missing DCI cases on survival estimates increased by age and was around 3% units for prostate and kidney cancers among the oldest patients. CONCLUSION: Young or middle-aged patients in Estonia experienced larger survival gain since the late 1990s than elderly patients. Decreasing quality of cancer registry data along with increasing patient age suggests less thorough clinical investigations in older age groups.

Sex differences in cancer survival in Estonia: a population-based study.

BACKGROUND: In Estonia, women have much longer life expectancy than men. The aim of this study was to examine sex differences in cancer survival in Estonia and to explore the role of age at diagnosis, stage at diagnosis and tumour subsite. METHODS: Using data from the population-based Estonian Cancer Registry, we examined the relative survival of adult patients diagnosed with nine common cancers in Estonia in 1995-2006 and followed up through 2011. Excess hazard ratios (EHR) of death associated with female gender adjusted for age, stage at diagnosis and tumour subsite were estimated. RESULTS: A total of 20 828 male and 13 166 female cases were analysed. The main data quality indicators were similar between men and women. Women had more cases with unknown extent of disease at diagnosis. Overall, the age-adjusted 5-year relative survival ratio was higher among women than men for all studied sites, but the difference was significant for cancers of mouth and pharynx (22% units), lung (5% units), skin melanoma (17% units) and kidney (8% units). The increase in survival over time was larger for women than men for cancers of mouth and pharynx, colon, rectum, kidney and skin melanoma. In multivariate analysis, women had a significantly lower EHR of death within five years after diagnosis for five of the nine cancers studied (cancers of mouth and pharynx, stomach, lung, skin melanoma and kidney). Adjustment for stage and subsite explained some, but not all of the women's advantage. CONCLUSIONS: We found a significant female survival advantage in Estonia for cancers of mouth and pharynx, stomach, lung, kidney and skin melanoma. The differences in favour of women tended to increase over time as from the 1990s to the 2000s, survival improved more among women than among men. A large part of the women's advantage is likely attributable to biological factors, but other factors, such as co-morbidities, treatment compliance or health behaviour, are also probable contributors to gender survival disparities in Estonia and merit further investigation. Our findings have implications for public health, early detection and cancer care in Estonia.

Childhood cancer survival in Europe 1999-2007: results of EUROCARE-5--a population-based study.

BACKGROUND: Survival and cure rates for childhood cancers in Europe have greatly improved over the past 40 years and are mostly good, although not in all European countries. The EUROCARE-5 survival study estimates survival of children diagnosed with cancer between 2000 and 2007, assesses whether survival differences among European countries have changed, and investigates changes from 1999 to 2007. METHODS: We analysed survival data for 157,499 children (age 0-14 years) diagnosed between Jan 1, 1978 and Dec 31, 2007. They came from 74 population-based cancer registries in 29 countries. We calculated observed, country-weighted 1-year, 3-year, and 5-year survival for major cancers and all cancers combined. For comparison between countries, we used the corrected group prognosis method to provide survival probabilities adjusted for multiple confounders (sex, age, period of diagnosis, and, for all cancers combined without CNS cancers, casemix). Age-adjusted survival differences by area and calendar period were calculated with period analysis and were given for all cancers combined and the major cancers. FINDINGS: We analysed 59,579 cases. For all cancers combined for children diagnosed in 2000-07, 1-year survival was 90.6% (95% CI 90.2-90.9), 3-year survival was 81.0 % (95% CI 80.5-81.4), and 5-year survival was 77.9% (95% CI 77.4-78.3). For all cancers combined, 5-year survival rose from 76.1% (74.4-77.7) for 1999-2001, to 79.1% (77.3-80.7) for 2005-07 (hazard ratio 0.973, 95% CI 0.965-0.982, p<0.0001). The greatest improvements were in eastern Europe, where 5-year survival rose from 65.2% (95% CI 63.1-67.3) in 1999-2001, to 70.2% (67.9-72.3) in 2005-07. Europe-wide average yearly change in mortality (hazard ratio) was 0.939 (95% CI 0.919-0.960) for acute lymphoid leukaemia, 0.959 (0.933-0.986) for acute myeloid leukaemia, and 0.940 (0.897-0.984) for non-Hodgkin lymphoma. Mortality for all of Europe did not change significantly for Hodgkin's lymphoma, Burkitt's lymphoma, CNS tumours, neuroblastoma, Wilms' tumour, Ewing's sarcoma, osteosarcoma, and rhabdomyosarcoma. Disparities for 5-year survival persisted between countries and regions, ranging from 70% to 82% (for 2005-07). INTERPRETATION: Several reasons might explain persisting inequalities. The lack of health-care resources is probably most important, especially in some eastern European countries with limited drug supply, lack of specialised centres with multidisciplinary teams, delayed diagnosis and treatment, poor management of treatment, and drug toxicity. In the short term, cross-border care and collaborative programmes could help to narrow the survival gaps in Europe. FUNDING: Italian Ministry of Health, European Commission, Compagnia di San Paolo Foundation.

Time trends in population-based breast cancer survival in Estonia: analysis by age and stage.

BACKGROUND: Survival from breast cancer (BC) in Estonia has been consistently among the lowest in Europe. The aim of this study was to examine most recent trends in BC survival in Estonia by age and stage. The trends in overall BC incidence and mortality are also shown in the paper. MATERIAL AND METHODS: Estonian Cancer Registry data on all cases of BC, diagnosed in women in Estonia during 1995-2007 (n = 7424) and followed up for vital status through 2009, were used to estimate relative survival ratios (RSR). Period hybrid approach was used to obtain the most recent estimates (2005-2009). Stage was classified as localized, local/regional spread or distant. RESULTS: BC incidence continued to rise throughout the study period, but mortality has been in steady decline since 2000. The distribution of patients shifted towards older age and earlier stage at diagnosis. Overall age-standardized five-year RSR increased from 63% in 1995-1999 to 74% in 2005-2009. Younger age groups experienced a more rapid improvement compared to women over 60. Significant survival increase was observed for both localized and locally/regionally spread BC with five-year RSRs reaching 96% and 70% in 2005-2009, respectively; the latest five-year RSR for distant BC was 11%. Survival for T4 tumors was poor and large age difference was seen for locally/regionally spread BC. CONCLUSIONS: Considerable improvement in BC survival was observed over the study period. Women under 60 benefited most from both earlier diagnosis and treatment advances of locally/regionally spread cancers. However, the survival gap with more developed countries persists. Further increase in survival, but also decline in BC mortality in Estonia could be achieved by facilitating early diagnosis in all age groups, but particularly among women over 60. Investigations should continue to clarify the underlying mechanisms of the stage-specific survival deficit in Estonia.