Screening studies in workers of modern carcinogenic enterprises

A carcinogenic enterprise is an enterprise where workers are exposed or may be exposed to industrial carcinogenic factors, and/or there is a potential danger of environmental contamination with carcinogens. This means that a worker may be exposed to carcinogenic substances at any stage of the production process, including its receipt, handling, storage, waste disposal, operation and repair of equipment.

The problem of occupational cancer currently occupies a leading place in the history of studying malignant neoplasms. This is primarily due to the widespread introduction and use of woodworking, rubber, and oil refining industries. And it is precisely these industries that make a significant contribution to the development of malignant neoplasms among workers in these industries.

A long latent period (15-18 years on average), indistinguishability of clinical and biological signs of tumors caused by exposure to a carcinogen at work from tumors caused by non-work factors, development of malignant neoplasms in workers who have left a carcinogenically hazardous production facility, an increase in the oncological risk due to exposure to concomitant unfavorable factors (smoking, alcohol abuse) - all these signs can make it difficult to determine the causative factor of a specific worker's disease. Therefore, it is very important to recognize pre-clinical signs of a malignant neoplasm in a still healthy worker in order to prevent the development of a clinically expressed form of a tumor, and, consequently, a premature decrease in the worker's ability to work and a deterioration in the quality of his subsequent life.

Currently, the most effective measures to combat malignant neoplasms in individuals employed in carcinogenically hazardous production are the formation of risk groups and early diagnostics of oncological diseases. Short-term tests based on the assessment of the genotoxicity of potential carcinogens are now actively used as methods of early diagnostics of oncological diseases. One of these methods is cytogenetic micronucleus analysis.

It should be noted that micronucleus analysis is generally available and relatively simple, as well as the ability to obtain the necessary information in a relatively short time.

The aim of the study is to determine the probability of the occurrence of a tumor process in workers of an enterprise with high technogenic pressure based on the study of cytogenetic status.

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Scope and methods of research

For cytogenetic analysis, 150 workers of the enterprise with a carcinogenic profile were examined, while workers who had acute pathology at the time of examination were not subjected to the study, and 100 people as a control group, whose professional activity is not associated with high man-made loads. Chemical compounds used at all stages of the technological process belong to class 1 (obligate carcinogens) and to class 2A with a high probability of tumor occurrence in humans (according to the classification of chemical carcinogens of the International Agency for Research on Cancer).

As a result, the micronucleus test was performed on 250 people (3 smears for each individual, a total of 750).

For statistical processing, all microkernel values are divided into four groups:

• 0.2-0.5%о - 1N - the level of micronuclei in a healthy person;
• 0.6-1.5%о - 2N - the level of micronuclei characteristic of the pre-disease state;
• 1.6-2.5%о - 3N - the level of micronuclei, characterizing the state of the body with a high probability of developing malignant neoplasms;
• more than 2.5% o-4N - the level of micronuclei, characterizing the state of the organism with a critical level of probability of developing malignant neoplasms.

A comparative analysis of the studied indicator of the micronuclei level of the study and control groups was carried out according to various characteristics (medical and biological characteristics: age, gender, presence of chronic pathology; production characteristics - profession, work experience).

Research results:

1. It was found that 7% of those examined had a level of erythrocytes with micronuclei, indicating instability of the genetic apparatus.
2. The average number of erythrocytes with micronuclei in the study group was 0.45+0.06%, which significantly differs from the number of erythrocytes with micronuclei in the control group (t= 4.824 at P<0.0001).
3. The most vulnerable age groups in terms of developing malignant neoplasms are those over 40 years of age. A significantly high percentage is the 40-49 year old group (36%). The second position in the age structure is occupied by the 50-59 year old group (25%). The active working age groups up to 29 and 30-39 years are represented in the ratio of 16% and 22%, respectively. The age group (over 60 years) makes up an insignificant part of the total number of those examined - less than 1%. Thus, among the total number of those examined, the majority (more than 60%) are people belonging to the age group over 40 years.
4. Micronucleus analysis data in women indicate a higher probability of developing oncopathology in the body compared to men (P<0.05).
5. Compared with the control group, the micronucleus analysis index in groups of people with and without chronic pathology is significantly higher. In people with a history of chronic pathology, the probability of developing oncopathology is significantly higher than the same index in the group of those examined without chronic diseases.
6. Among all professional groups, the level of micronuclei is higher than the control group. Reliable values are noted among laboratory assistants, machine operators, machinists, fitters, drivers, cleaners, rollers, and loaders.
7. A reliably high average micronucleus test level was found in the professional group “apparatus operator”, which is close to the 2N coefficient, which determines the average risk of developing malignant neoplasms.
8. A high risk of developing malignant neoplasms exists among groups with experience of 10-19 years, 20-29 years, 30-34 years, and the lowest - with experience of up to 9 years.

Conclusion

Determination of the cytogenetic status of workers in carcinogenic industries allows identifying risk groups for the development of oncological diseases and can be used as a screening method in combination with other methods for early pre-clinical diagnostics of work-related malignant neoplasms.

Doctor of Medical Sciences, Professor of the Department of Hygiene, Occupational Medicine with a Course in Medical Ecology Irina Dmitrievna Sitdikova. Screening studies of workers of modern enterprises with a carcinogenic profile // Practical Medicine. 8 (64) December 2012 / Volume 1