Medical Radiology and Radiation Safety. 2022. Vol. 67. № 2

Risk of prostate cancer among Chernobyl clean-up workers,
1996-2018

А.I. Gorski¹, М.А. Maksioutov¹, K.A. Tumanov¹, E.V. Kochergina¹, V.K. Ivanov¹, S.A. Ivanov¹, A.D. Kaprin²

¹ A.F. Tsyb Medical Radiological Research Centre – branch of the National Medical Research Radiological Centre, Obninsk, Russia

² National Medical Research Radiological Centre, Moscow, Russia

Contact person: A.I. Gorski, e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

ABSTRACT

Purpose: The paper deals with the occurrence of prostate cancer and mean survival time following a diagnosis of the disease among Chernobyl clean-up workers.

Material and methods: Clinical and dosimetry data accumulated at the National Radiation and Epidemiological Registry (NRER) during the period from 1996 over 2018 were used for the study. The study cohort consisted of 69,698 men. During the follow-up 742 prostate cancer cases were detected, all patients had radiation dose records, the disease stage was established in 628 patients. To assess radiation risk maximum likelihood approach was used. Mean survival time was evaluated with the use of the relationship between a disease prevalence and newly detected disease cases intensity in a stationary population (diseases intensity is equal to intensity of mortality from all causes).

Results: Excess relative risk of prostate cancer induction per 1 Gy was 0.74 (95 % CI: ‒0.31; 2.15) and it was statistically insignificant. Standardized incidence ratios between clean-up workers and male population of Russia within 95 % confidence limits do not differ from 1.0. Mean survival time after the disease diagnosis within the period from 1996 over 2018 was 3.5±1.3 years. The relationship between a survival time and a disease stage was estimated. Survival time for cases with 1–3 stages 3.3±2.9, 3.6±2.3, 4.3±2.7 years respectively. The less survival time for cases with stage 4 was 1.5±0.8 years. Mean mortality rate, i.e. the ratio of the number of clean-up workers died from prostate cancer to the total number of clean-up workers with diagnosed prostate cancer was 36.8 %, for stages 1–4 it was  20, 16, 37, 74 % respectively. Mean survival time in the groups with doses less than and higher than 150 mGy was 3.4±1.4 and 3.7±1.7, respectively. Presented data confirm the null hypothesis that there is no difference in survival times (p=0.20).

Conclusion: Increase in prostate cancer incidence becomes the social problem not only in Russia but in other countries as well. The paper presents results of comprehensive radiation epidemiological analysis of prostate cancer incidence in cleanup workers, who constitute the representative sample of the Russian male population. The dose ‒ prostate cancer incidence relationship for the follow-up period from 1996 over 2018 is not statistically significant, although the value of excess relative risk per dose unit is positive. It is not unthinkable that the absence of statistical significance is caused due to limited length of the follow-up period. But at the same time, the fact that observed the standardized incidence ratio is 1.0 and characteristics of two groups with doses ≥150 mGy are similar, speaks of the lack of a significant radiation effect. The obtained results of the analysis confirm our view of the necessity to continue the study.

Key words: prostate cancer, morbidity, Chernobyl clean-up workers (liquidators), National Radiation and Epidemiological Registry, radiation risk, average survival time after diagnosis, tumor stage

For citation: Gorski АI, Maksioutov МА, Tumanov KA, Kochergina EV, Ivanov VK, Ivano SA, Kaprin AD. Risk of prostate cancer among Chernobyl clean-up workers, 1996-2018. Medical Radiology and Radiation Safety. 2022;67(2):25-31. (In Russian)
doi: 10.33266/1024-6177-2022-67-2-25-31

References

1. Aksel YE.M., Matveyev V.B. Statistics of Malignant Tumors of Urinary and Male Urogenital Organs in Russia and the Countries of the Former USSR. Onkourologiya = Cancer Urology. 2019;15;2:15–24. (In Russian).

2. Ed. Kaprin A.D., Starinskiy V.V., Petrova G.V. Zlokachestvennyye Novoobrazovaniya v Rossii v 2018 Godu (Zabolevayemost i Smertnost) = Malignant Tumors in Russia in 2018 (Morbidity and Mortality). Moscow Publ., 2019. 250 p. (In Russian).

3. Ivanov V.K., Maksyutov M.A., Tumanov K.A., et al. 35-Year Experience in the Functioning of the National Radiation and Epidemiological Registry as a State Information System for Monitoring the Radiological Consequences of the Chernobyl Accident. Radiatsiya i risk = Radiation and Risk. 2021;30;1:7–39. (In Russian).

4. Ed. Sobin L.Kh., et al. TNM. Klassifikatsiya Zlokachestvennykh Opukholey = TNM. Classification of Malignant Tumors. Moscow, Logosphera Publ., 2011. 304 p. (In Russian).

5. Ivanov V.K., Gorskiy A.I., Kashcheev V.V., et al. Latent Period in Induction of Radiogenic Solid Tumors in the Cohort of Emergency Workers. Radiat. Environ. Biophys. 2009;48;3:247–252.

6. Gorskiy A.I., Kashcheev V.V., Tumanov K.A. Latent Period in Induction of Radiogenic Solid Tumors in the Cohort of Emergency Workers. Radiatsiya i risk = Radiation and Risk. 2008;17;2:30–38. (In Russian).

7. Rothman K.J., Greenland S., Lash T.L. Modern Epidemiology. Philadelphia, PA, Lippincott Williams & Wilkins, 2008. 758 p.

8. Ed. Lloyd E., Lederman U. Handbook of Applied Statistics. Moscow, Finances and Statistics Publ., 1989. 508 p. (In Russian).

9. Breslow N.E., Day N.E. Statistical Methods in Cancer Research. V.2. IARC Scientific Publication No 82. Lyon, IARC, 1987.

10. Gorskiy A.I., Maksyutov M.A., Tumanov K.A., et al. Impact of the Radiation Factor on Mean Survival Time for Chernobyl Clean-up Workers with Solid Cancer. Biology Bulletin. 2019;46;11:1530–1537.

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Conflict of interest. The authors declare no conflict of interest.

Financing. The study had no sponsorship.

Contribution. Article was prepared with equal participation of the authors.

Article received: 30.11.2021. Accepted for publication: 30.03.2022.