Indications.
Lung cancer has become the malignant tumor with the highest incidence rate among men and women, with a male to female ratio of 1.4/1; 98% of the age of onset was greater than 40 years old, and 90% was greater than 50 years old.
All 25 cases of lung cancer in a group of census cases were located in the age group of 50-69 years, accounting for 1.6%-1,9% of the population participating in the census, with a male to female ratio of 1.7/1. The Japanese Anti-Lung Cancer Action (ALCA) conducted CT screening on 9,998 men and women over 40 years of age in 1993, and the incidence of lung cancer was 0.4% (36/9998). The incidence of lung cancer was 0.4% (36/9998). In 1998, the Early Lung Cancer Action Program (ELCAP) conducted CT screening of lung cancer in 1000 men over 60 years of age who smoked, and the incidence of lung cancer was 2.7% (27/1000).
Some scholars believe that all men over 40 years of age can be considered for screening, because with the advancement of CT technology, the application of multi-layer spiral CT and even flat panel CT can detect smaller lesions, and lung cancer detected after the age of 50 may be detected by CT at the age of 40; therefore, it is advocated that CT screening studies for high-risk groups over 40 years of age are the recommended indications for lung cancer CT screening studies. The proposed indication is based on the study of the epidemiological characteristics of lung cancer.
Epidemiological characteristics.
1. Temporal trends.
The mortality rate of lung cancer in men in developed countries such as the United Kingdom and the United States has increased dramatically since the turn of the century. In the United States, lung cancer ranks first among cancers, accounting for 28,6% of all cancer deaths. Currently, this trend has spread throughout the world; lung cancer incidence and mortality rates in developed countries are maintained at a high level. Since around 1960s, the incidence of lung cancer in women has also gradually increased.
The mortality rate of lung cancer in China, especially in men, is rapidly increasing.
2.Regional distribution.
Many developed countries and regions are the high incidence areas of lung cancer, and the most prevalent regions in order are: Europe, Russia, North America, South America, Australia/New Zealand, West and Southeast Asia, and Croatia/Bolivia.
The level of lung cancer mortality in China’s provinces, cities and autonomous regions shows a gradual downward trend from northeast to southwest and from east to west. The three points with the highest lung cancer mortality rates in China are, in order, in the city of Jialao, Yunnan Province (93, 85/100,000), in the city of Chongqing (87, 74/100,000), and in Liwan District, Guangzhou City (80, 56/100,000), all of which are more than three times the national level.
3.Population distribution.
Lung cancer incidence and mortality rates rise with age, rare before the age of 10, rising rapidly after the age of 40 and reaching a peak around the age of 70, with the main age of death being 35-69 and declining thereafter.
The mortality rate of both men and women increases gradually with age, and the difference is greater in men than in women, and the difference increases with age; the mortality rate of lung cancer in men rises early, fast and large; after the age of 80, the mortality rate of lung cancer in men decreases, and the difference in mortality rate of lung cancer in men and women only decreases slightly; among women with lung cancer, Chinese women are more common than non-Chinese women.
Risk factors of lung cancer.
1.Smoking
2.Air pollution
3.Occupational factors
4.Other
Prevention of lung cancer.
1.Control smoking
2.Improve environment
3.Other measures