Global Statistics and Demographic Factors
Cancer is one of the leading causes of mortality worldwide. According to medical statistics, there are approximately 5.9 million patients globally. Tumors firmly hold the second place among causes of death. There is a well-founded prediction that in the 21st century, against the background of successful reductions in cardiovascular mortality, neoplasms may take first place.
Economic status plays an important role: half of all cancer deaths occur in economically developed countries. Furthermore, tumor growth is a prominent gerontological problem. Although incidence increases across all age categories, the absolute maximum is detected in individuals over 50 years of age.
Regarding gender differences, males are affected by neoplasms 1.5 times more often than females, and in older age groups, this figure exceeds the female rate by more than 2 times. The incidence rate historically reaches significant levels per 100,000 population, with first-year mortality following diagnosis remaining notably high.
Geographical Variability and Environmental Impact
Morbidity and mortality rates are highly heterogeneous and depend on multiple factors: the ecological environment, ethnic habits, population genetics, and heredity.
A striking example of geographical differences is the comparison between Japan and the USA:
- Gastric cancer mortality in Japan is 8 times higher than in the United States.
- Breast cancer mortality in Japanese women is only 1/4 of the corresponding figure in the USA.
- Prostate cancer mortality in Japan is equal to 1/5 of the American data.
However, these differences are not exclusively genetic. Social conditions and migration can completely neutralize ethnic risks. For example, Japanese-Americans who moved to the USA develop gastric cancer at the same frequency as the local population, losing the high incidence specific to Japan.
Significant social risk factors also include working conditions and past illnesses. For instance, lung cancer is diagnosed significantly more often in individuals living or working near hazardous industries, as well as in patients with a history of tuberculosis.
Incidence Structure: Global and Regional
The structure of cancer incidence has specific features depending on sex and region. Globally and regionally, the following trends are observed:
| Sex | Global Statistics | Regional Statistics |
|---|---|---|
| Males | 1. Lung (stabilization)<br>2. Stomach<br>3. Colon (increasing) | 1. Lung<br>2. Stomach<br>3. Skin |
| Females | 1–3 shared by: Breast, Uterus, Colon | 1. Breast<br>2. Skin<br>3. Stomach |
Trends and Prevention
The epidemiological picture is not static: there is a constant shift in the structure of incidence, manifested by an increase in certain types of tumors and a decrease in the frequency of others. Globally, both incidence and mortality are rising.
Nevertheless, effective prevention can reverse negative trends. A decrease in incidence is directly related to the implementation of effective restrictive and environmental measures. A classic example of successful prevention is the experience of the USA: the introduction of strict smoking bans in public places combined with rigorous control of carcinogenic benzpyrene emissions led to the successful stabilization of lung cancer incidence rates.