MALIGNANT TUMORS IN PEDIATRIC POPULATION OF UKRAINE: TRENDS AND STRUCTURAL FEATURES.

The creation of a central bank of personalized information of cancer patients, including children, allowed to obtain objective data and establish continuous cancer surveillance in the child population in Ukraine. The aim of the study was to analyze the dynamics of cancer incidence (1989-2019) and mortality (1999-2019) based on the 3rd revision of International Classification of Childhood Cancer (ICCC-3). MATERIALS AND METHODS: A study cohort includes 31,537 patients aged 0-19 years at the time of diagnosis in 1989-2019, registered in Ukrainian population. RESULTS: The major groups of malignancies in the child population are presented by leukemia, lymphomas, central nervous system (CNS) tumors, epithelial neoplasms, bone cancer and soft tissues sarcomas. There were observed no gender differences in cancer incidence, except germ cell tumors and trophoblastic tumors, gonadal malignancies, as well as some other malignant epithelial neoplasms, with their proportion being twice higher in the female population. Our analysis showed a trend towards increase in the incidence of leukemia, CNS neoplasms, neuroblastoma, trophoblastic tumors and epithelial malignancies; decrease in the incidence of lymphomas and bone neoplasms; stabilization in the incidence of malignancies of liver and kidneys. The dynamic changes in cancer mortality in the studied cohort were observed, namely, the decrease of mortality from leukemias and lymphomas in males (but not in females), along with the increase of mortality from CNS neoplasms, neuroblastoma, soft tissues sarcomas and germ cell tumors, regardless of gender. CONCLUSIONS: The analysis and presentation of the epidemiological data on children's malignancies implementing ICCC-3 classification for all relevant records in the National Cancer Registry of Ukraine allows for evaluating the major trends of cancer incidence and mortality in Ukrainian pediatric population, taking into account tumor morphology, topography, gender and age.

Burden of malignant melanoma in Ukraine in 2002-2013: incidence, mortality and survival.

BACKGROUND: The malignant melanoma (MM) incidence rates were increasing and later stabilizing in many regions of the world, while in South-Eastern Europe incidence rates are uniformly increasing and mortality rates are higher. AIM: To describe burden of MM in Ukraine in terms of incidence, mortality and survival by sex, age and stage for the period 2002-2013 and compare with European countries. MATERIALS AND METHODS: Database of the National Cancer Registry of Ukraine was used to extract MM incidence cases; number of MM deaths was obtained from the official mortality statistics. Age-standardised and age-specific incidence and mortality rates were calculated by sex, age groups (15-39, 40-59 and 60+); estimated annual percent of change was used to describe trends. Proportions of new cases by stage of disease and calendar period (2002-2007 vs 2008-2013) were compared as well as net survival estimates. RESULTS: In Ukraine, MM was more common in females (age-standardised 5.3 per 100,000 in 2013; annual percent of change 3.5%) than in males (5.1 per 100,000; 4.1%); around 50% of them diagnosed in the age group 60+. The observed increase in proportion of new cases with early stage (I-II) was due to stage II cases. The slight increase in mortality rates in males or stability in females were not accompanied with increase of survival. Net MM survival was consistently lower comparing to European countries. CONCLUSION: More resources should be targeted to increase the capacity of healthcare in diagnostics and treatment of malignant melanoma, but also in promoting healthcare and education in Ukraine.

INCIDENCE OF MALIGNANT NEOPLASMS AMONG RESIDENTS OF SMALL RADIONUCLIDE-CONTAMINATED CHORNOBYL DISTRICTS IN A POST-ACCIDENT PERIOD. / ZAKhVORIuVANIST' NA ZLOIaKISNI NOVOUTVORENNIa MEShKANTsIV MALYKh ZABRUDNENYKh RADIONUKLIDAMY TERYTORIAL'NYKh ODYNYTs' ChORNOBYL'S'KOGO REGIONU U VIDDALENOMU PISLIaAVARIINOMU PERIODI.

OBJECTIVE: To assess the level of risks of development of malignant neoplasms among the residents of smallChornobyl districts («rayons¼) in connection with low-dose radiation exposure and its dynamic changes. MATERIALS AND METHODS: The study population included residents of Borodianka, Ivankiv and Poliske districts ofKyiv region («oblast¼) and Luhyny, Narodychi and Ovruch districts of Zhytomyr region, 175,100 inhabitants in2017. The study period was 1980-2017. All cancers incidence rates as well as rates of potentially radiation-associated sites (breast, thyroid, hematopoietic and lymphoid systems) were calculated and analysed. Methods of variation statistics, descriptive and analytical epidemiology were used. RESULTS: The impact of ionizing radiation on population of the most radionuclide-contaminated districts raisesconcerns of the potential threat of adverse cancer effects, especially thyroid cancer. The average total whole-bodyeffective radiation doses received due to cesium during long time (1986-2005) among residents of the study districts (7.6-45.8 mSv) exceeded that in Zhytomyr (5.9 mSv), Kyiv (4.9 mSv) regions and Ukraine as a whole (2.48mSv), but also in other districts in the North Ukraine. The average doses of internal radiation absorbed by the thyroid gland (161-1559 mGy) among the most vulnerable population - children and adolescents (aged 0-18 yearsat the time of the accident) of these areas, and obtained in the short post-accident period, significantly exceedthat in Zhytomyr (87 mGy), Kyiv (81 mGy) regions and Ukraine as a whole (19 mGy). Irradiation rates of adult residents of these territories were lower, but significantly exceeded the average doses received by the population ofUkraine and large administrative units. Overall cancer incidence in the 6 districts during pre- and post-accidentperiods was lower comparing to Ukraine's and Kyiv region's rates, and did not significantly differ from Zhytomyrregion's rates. At the same time, the incidence rates of thyroid cancer significantly exceeded that of the pre-accident period as well as Zhytomyr region's rates. CONCLUSIONS: The results of the study indicate needs for further monitoring of malignant neoplasms not only inthe population of Ukraine as a whole and its large administrative-territorial units, but also among residents of particular areas, given the likelihood of the realization of the risks of radiation-associated diseases in the distantpost-accident period in accordance with local environmental conditions.

Incidence and long-term effects of treatment of malignant germ cell neoplasms in Ukraine.

AIM: To describe incidence of malignant germ cell neoplasms (GCNs) in Ukraine and assess the medical care to patients with GCNs and its efficacy. MATERIALS AND METHODS: Records on 6495 males and 1038 females with malignant GCNs diagnosed in 2000-2013 extracted from the database of National Cancer Registry of Ukraine have been analyzed using methods of descriptive epidemiology and survival evaluation. RESULTS: In Ukraine, GCNs covered 79.1% of testicular cancers and 48.9% of ovarian cancers in patients aged 0-19 years, while their proportions in total cancer incidence did not exceed 0.7% in males and 0.1% in females. Most of GCNs in males (75.9%) were diagnosed at the reproductive age (20-49) and in females 72.2% of GCNs were diagnosed at the age of 0-44 years. Female gonadal GCNs were divided by germinomatous and nongerminomatous as 49.3% vs 50.7% while in males this proportion was 65.3% vs 34.7%. Age-specific incidence of genital GCNs in Ukraine reached peak values in males aged 25-39 years and in females aged 10-24 years. Nonseminomatous testicular GCN cases were more common than seminomatous cases in males until the age of 30 years with an incidence of seminomas peaked 10 years later than non-seminomas. Ovarian germinomas were more common than non-germinomas in females aged 15-29. Total GCN incidence rate in 2013 was 1.99 ± 0.090/0000 in males and 0.32 ± 0.040/0000 in females, being closer to that in the countries of Eastern Europe and Asia. In Ukraine, 5-year survival of patients with testicular GCN of stage I who received surgery combined with chemotherapy or radiotherapy was lower than that reported for Europe and USA, and substantially lower in patients with stages II-IV. Five-year survival of patients with ovarian GCN treated with surgery plus chemotherapy was close to that reported in a study for populations of European countries. CONCLUSION: The trends and patterns of GCN incidence in Ukraine are similar to those in other European countries, while patterns of treatment and survival in Ukraine are closer to that in countries in transition. Further research and analysis are impossible without due registration of both the diagnosis and the treatment undertaken as well as close follow-up of patients' life status.

EPIDEMIOLOGY OF BREAST CANCER IN UKRAINE WITH CONSIDERATION OF THE FACTORS OF THE CHORNOBYL ACCIDENT. / EPIDEMIOLOGIIa RAKU MOLOChNOÏ ZALOZY V UKRAÏNI Z URAKhUVANNIaM FAKTORIV RYZYKU ChORNOBYL'S'KOÏ AVARIÏ.

OBJECTIVE: Assessment of the possible impact of the Chornobyl accident on the incidence of breast cancer in the female population of Ukraine as a whole and in some affected groups. OBJECT OF THE STUDY: The female population of Ukraine as a whole and in separate groups of victims - women par- ticipating in the clean-up works in 1986-1987, evacuaees from the exclusion zone and inhabitants of the territo- ries most contaminated with radionuclides. METHODS: Statistical, mathematical, cartographic. RESULTS: This study, covering a significant period of time (1976-2016), revealed a steady temporal and territorial agglomeration of regions with a higher incidence of breast cancer in the southern and south-eastern regions of Ukraine. Lower - in the western and northern regions. There is a steady increase in the incidence rate, but in recent years this growth has slowed down. The epidemiological situation regarding the incidence of breast cancer in the female population of Ukraine during the 30 years after the Chornobyl accident is generally stable. At the same time, a marked increase in the frequency of this pathology in the groups of the affected population, especially in women, participated in clean-up works in 1986-1987. CONCLUSIONS: A stable agglomeration of regions with high levels of incidence in the south and south-east, and low in the west and north of the country is determined. The dynamics of breast cancer in Ukraine as a whole is characterized by steady growth, although in recent years its pace has slightly decreased. Among the individual population groups affected by the Chornobyl catastrophe (female liquidators, evacuated women from the exclusion zone, residents of the most contaminated with radionuclides territories) only among female liquidators of 1986-1987 the significant in- crease was observed in the incidence of breast cancer, which exceeds the national indicators at 1.3-1.6 times.

RADIATION RISKS OF THYROID CANCER IN CHORNOBYL CLEAN-UP WORKERS USING THE ALTERNATIVE ESTIMATES OF DOSES OF EXTERNAL EXPOSURE. / RADIATsIINI RYZYKY RAKU ShchYTOPODIBNOÏ ZALOZY V UChASNYKIV LIKVIDATsIÏ AVARIÏ NA ChAES Z URAKhUVANNIaM AL'TERNATYVNYKh OTsINOK DOZ ZOVNIShN'OGO OPROMINENNIa.

OBJECTIVE: The objective of this study was to estimate the thyroid cancer radiation risks - excess absolute risk(EAR), excess relative risk (ERR) and attributable fraction of risk (AR) in the cohort of 150,813 Ukrainian male clean-up workers during the 1986-2012 period (more than 25 years after the Chornobyl accident). MATERIALS AND METHODS: The cohort under study of 150,813 Ukrainian men who participated emergency and clean-up work in 1986-1990 was formed based on the data of the Ukrainian State Register of persons affected due toChornobyl accident (SRU). The identification of thyroid cancer cases (216) was carried out by linking the SRU data-base with the National Cancer Registry of Ukraine (NCRU) data. Standardised incidence ratios (SIR) were estimatedcomparing thyroid cancer incidence in the cohort with the corresponding national indices. Excess absolute risk(EAR), excess relative risk (ERR) and attributable fraction of risk (AR) were calculated accounting for the alterna-tive dose estimates. The following sources of the average dose values for Ukrainian liquidators were used: officialtotal external dose records according to UNSCEAR 2008 report and results of external red bone marrow dose recon-struction by the RADRUE method for the cohort sample. For the radiation risk evaluation, these estimates were con-versed to the average external thyroid dose. RESULTS: Results of the long term study (1986-2012) of thyroid cancer risks in a cohort of 150813 Chornobyl clean-up workers («liquidators¼) from Ukraine are presented. Two options for the average thyroid dose estimates were usedfor radiation risks evaluation. According to the SRU and NCRU 216 incident thyroid cancers were diagnosed in 1986-2012 within the studied cohort with an overall SIR of 3.35 (95 % confidence interval (CI) 2.51-3.80). The SIR esti-mates were elevated throughout the entire follow-up period. Investigation of a contribution of the external expo-sure (according to the alternative values) showed the elevated dose associated thyroid cancer rates in the studiedcohort. Alternatively estimated EAR/104 PY Gy were of 1.86 (95 % CI 0.47-3.24) and 2.07 (95 % CI 0.53-3.62);ERR/Gy - 2.38 (95 % CI 0.60-4.15) and 2.66 (95 % CI 0.68-4.64) and AR % (Gy) 70.4 % and 72.7 % Gy. CONCLUSIONS: Obtained results prove the dose dependent increase of thyroid cancer incidence among UkrainianChornobyl clean-up workers. These conclusions are consistent with those received for combined cohort of Belarus,Russia and Baltic States liquidators.

Incidence of multiple myeloma among cleanup workers of the Chornobyl accident and their survival.

The study presents the updated data on the multiple myeloma (MM) incidence in Ukrainian cleanup workers after the Chornobyl accident and their survival. The epidemiological analysis is based on the extended follow-up period to identify new MM cases for higher statistical power and to collect additional data on the disease course and outcome for the survival analysis. The objective of the study was to analyze the MM incidence and survival in Chornobyl cleanup workers in 1996-2013 in comparison with the national MM statistical data. MATERIALS AND METHODS: A study cohort consisted of 152,520 male cleanup workers resided in one of 6 regions of Ukraine or Kyiv city and registered in the Ukrainian State Chornobyl Registry (SChR). The Cohort Database was linked to the Ukrainian National Cancer Registry (NCR) Database to identify MM cases and to analyze MM incidence in 1996-2013. Standardized incidence ratios (SIR) for MM over the period 1996-2013 were calculated as compared to the general population of Ukraine. A 10-year lag period (when incident cases are not considered radiation-related) was applied. One-year and 5-year cause-specific survival of MM cases were calculated as percentage of those who were alive correspondingly for 1 or 5 years after diagnosis among overall diagnosed. By the moment, the 5-year survival rate either for the sub-period 2008-2013 or for the whole study period 1996-2013 cannot be determined. Vital status data were updated according to the recent SChR and NCR information. RESULTS: 75 MM cases diagnosed in 1986-2013 were identified in the studied cohort. 69 of them were included to the incidence analysis considering a 10-year lag period. While the incidence over 15 years after the accident did not differ significantly from the corresponding rate in general population of Ukraine, a tendency to increase was seen in the period from 16 to 21 years after the accident, and significantly increased SIR estimate was revealed for 2008-2013 (SIR 1.86, 95% confidence interval (CI) 1.27-2.44). The highest incidence was detected in 2008-2013 among cohort members diagnosed over the age of 50 years mostly due to the significant excess among those aged 60-69 (SIR 2.46, 95% CI 1.32-3.59). Survival rates in cleanup workers were shown to be higher than in the general population of Ukraine (73.9% and up to 65.0%, respectively). CONCLUSIONS: SIR for the 2008-2013 period, 22-27 years after the accident, demonstrated the significant excess of MM incidence among male cleanup workers. Survival of MM cases is higher in cleanup workers in comparison with that in general population. This article is a part of a Special Issue entitled "The Chornobyl Nuclear Accident: Thirty Years After".

Experience of study of the incidence of malignant neoplasms population in small areas of Ukraine, which suffered contamination with radionuclides due to the Chornobyl accident. / Dosvid doslidzhennia zakhvoriuvanosti na zloiakisni novoutvorennia naselennia malykh terytorii Ukrainy, shcho zaznaly zabrudnennia radionuklidamy vnaslidok avarii na Chornobyl's'kii AES.

GOAL OF THE STUDY: to evaluate the dynamics of implementation risks of malignant tumors in some small areas of Ukraine in the pre- and post-accident period. MATERIALS AND METHODS: The study population group - the population of the Malyn rayon, Zhytomyr region. The period of observation covered 1980-2014. There was investigated the incidence of malignant tumors in general and individual nosological forms (thyroid cancer, breast cancer, tumors of hematopoietic and lymphoid system). Methods of variation statistics and descriptive epidemiology were used. RESULTS: Characteristics of ionizing radiation influence on the population of Malyn rayon indicate the potential for negative effects, especially for thyroid cancer. Besides the fact that the average total effective radiation dose whole body by radioactive cesium in Malyn rayon population (5.9 mSv) are at medium level in Zhytomyr region and is significantly lower in comparison with those of other areas of the northern part of the oblast, the exposure of thyroid 236 mGy, is significantly higher than the regional figures - 81 mGy. Although the level of morbidity Malyn rayon of malignant tumors in general was about at the national level for 1999-2003 and lower it in the 2012-2014, exceeding the figures of Zhytomyr region, the incidence of thyroid cancer in the 2012-2014 in Malin area was 1.7 times higher in comparison with data for Ukraine and in 1.9 times in comparison with the data in Zhytomyr region. As in most northern areas that fell under radioactive iodine fallouts, there is the realization of increased radiation risk of cancer of this organ. The incidence of breast cancer in female population Malyn rayon is the lowest in comparison with Ukraine and Zhitomir regions. However, the rate of increase in this area is the highest. CONCLUSIONS: The results indicate the need for further monitoring of occurrence of cancer cases in the population of not only Ukraine as a whole, or large administrative units, but also among the population in small areas, taking into account the probability of the realization of risks of radiation-associated disease cases according to local environmental conditions.

Quarter of century since the Chornobyl accident: сancer risks in affected groups of population. / Chvert'' stolittja pislja Chornobyl''s''koi' avarii': ryzyk raku v grupah postrazhdalogo naselennja.

Objective. The goal of this study was to define levels and dynamic trends of cancer incidence at whole and some separate sites in groups of Ukrainian population affected by the Chornobyl accident during a long period of observation. Materials and methods. Those groups were Chornobyl accident recovery operation workers (CRW) of 1986-1987 years of participation, evacuees from Prypyat town and 30-km zone and residents of the most contaminated territories of Ukraine. Analysis was carried out with the standard methods of descriptive epidemiology: calculation of crude, age-specific and age-adjusted incidence rates with standard errors and confidence intervals. Results, discussion and conclusions. This study showed that all cancer incidences exceeded the national level only in CRW group. Decrease of cancer incidence rate in the recent years might be caused by shortened average life expectancy in Ukrainian population, especially in males. Statistically significant increase of leukemia incidence in CRW group was registered as well. Besides, in all three main affected groups there was revealed significant excess of thyroid cancer. Irradiation of thyroid due to radioactive iodine fallouts might be a main cause of this phenomenon. Increase of thyroid cancer incidence was registered not only in children, but also in adolescents and adults. Appearance of excess thyroid cancer cases as an effect of radiation exposure tends to increase during the time. Significant excess was also revealed for breast cancer in female CRW group. Because latency period for different nosological forms of radiation-induced malignant tumors varies widely, profound attention in further studies should be drawn not only to thyroid, breast cancers and leukemia, but also to malignancies with longer latent period: lung, stomach, colon, ovary, urinary bladder, kidney cancer and multiple myeloma.

Age and gender patterns of thyroid cancer incidence in Ukraine depending on thyroid radiation doses from radioactive iodine exposure after the Chornobyl NPP accident.

UNLABELLED: The objective of this study was to investigate the thyroid cancer incidence in a whole territory of Ukraine and to clear up its age and gender patterns depending on average regional (oblast) thyroid doses from radioactive iodine due to the Chornobyl accident. MATERIALS AND METHODS. On the basis of average accumulated thyroid doses from radioactive iodine the geographical regions of Ukraine with low and high average thyroid doses were identified for a comparative analysis performance. Methods of descriptive epidemiology were used. RESULTS: The level and dynamics of thyroid cancer incidence were analyzed in different gender and age groups (both for attained age and age at the moment of the Chornobyl accident). Results of this study confirmed the radiation excess of thyroid cancer in individuals who were children and adolescents in 1986. Some excess was observed in elder age groups too. Especial situation was observed in female age group 40-49 at the moment of the Chornobyl accident i.e. the age-specific thyroid cancer incidence rates were significantly higher in "high exposure" regions comparing with "low exposure" ones during all years of observation within 1989-2009. CONCLUSIONS: A probable radiation excess of thyroid cancer was suggested not only in children and adolescents but also in adult age groups. In elder age groups this excess was less expressed and manifested after a longer period of time. The origin of the phenomenon in female age group of 40-49 is unclear now. Hypothesis of combined effect of radiation and natural changing of hormonal status in this age should be checked in the future studies.