When and how does lung cancer screening start?

*It is only for medical professionals to read for reference.
Don't be careless, come and see if you are at high risk of lung cancer? Lung cancer is the cancer with the highest morbidity and mortality in China, and it is one of the major diseases that seriously threaten people's lives and health
.

Data show that among the new global lung cancer cases in 2020, about 37% will come from China
.

Among the deaths from lung cancer, Chinese cases accounted for about 39.
8%
.

"Early diagnosis and early treatment" is the most important and effective method to improve the survival rate of lung cancer patients and reduce the mortality of patients
.

Therefore, the screening of lung cancer for high-risk groups of lung cancer is the basis for achieving "early diagnosis and early treatment" for lung cancer patients, and is a key factor in reducing their mortality and prolonging survival
.

Who needs to be screened? Take a look at what the major guides say! USPSTF Guidelines: The age for lung cancer screening should be advanced to 50! On October 12, the United States Preventive Services Task Force (USPSTF) updated the lung cancer screening recommendations for 2021 [1,2], further expanding the scope of lung cancer screening populations
.

The previous version (2013 version) of the USPSTF guidelines recommends that for adults 55-80 years old, smoking intensity above 30 pack years (pack year = number of packs smoked per day × number of years of smoking), and people who quit smoking less than 15 years, Low-dose spiral CT (LDCT) lung cancer screening is performed annually
.

The 2021 version of the USPSTF guidelines advances the age recommendation for lung cancer screening population to 50, and the smoking intensity recommendation is reduced from 30 pack-years to 20 pack-years.
This means that more non-lung cancer high-risk groups are also included in the "lung cancer high-risk group" "In the ranks
.

This guideline update is based on the report of the NELSON study [3].
The results of the NELSON study show that in the age of 50-74, the smoking history is ≥15 cigarettes per day, duration ≥25 years, or smoking ≥10 per day Among those who lasted ≥30 years and quit smoking less than 10 years, compared with those who did not undergo screening, those who had undergone 4 LDCT screenings within 5.
5 years had a 25% reduction in lung cancer mortality
.

How to screen high-risk groups? Look at the recommendations of domestic and foreign guidelines.
Because the characteristics of the domestic population are quite different from those of the Western population, the epidemiological characteristics of domestic tumors are also different from those of foreign countries.
The relevant indicators in foreign lung cancer screening guidelines may not be fully applicable to China.
This leads to slightly different definitions in the Chinese and American guidelines
.

1.
Compared with foreign guidelines, domestic guidelines suggest ages for screening populations earlier
.

"Whether it is the updated USPSTF guidelines, the National Comprehensive Cancer Network (NCCN) guidelines [4,5] that have great influence in the country, or the American College of Chest Physicians (ACCP) guidelines [6], etc.
The age limit for lung cancer screening is limited to 55 years old
.

Many domestic guidelines recommend that people over the age of 50 begin to receive lung cancer screening, and the "Chinese Expert Consensus on Lung Cancer Screening and Management (2019)"[7] is even more important.
It is recommended that people over the age of 40 start lung cancer screening
.
The
editorial published by Academician Hejie in the international authoritative journal Journal of Thoracic Oncology introducing the status quo of lung cancer screening and prevention and treatment in China and the progress of treatment pointed out that under the age of 40, certain age groups The incidence of lung cancer in China is relatively low, and has since risen sharply, reaching a peak in both men and women in the 80 to 84-year-old age group
.

Prior to this, the incidence of lung cancer in women was significantly lower than that of men
.

Figure 1 Morbidity and mortality of specific age groups per 100,000 population in 2014.
2.
Domestic guidelines set the limits of smoking intensity for screening populations more advanced.
"In addition to this screening age, the screening limits for smoking history of smoking populations There are also certain differences.
Although the USPSTF guidelines have been updated to reduce the screening limit for smoking history of smokers from 30 pack years to 20 pack years, many foreign guidelines still regard people with a history of smoking ≥ 30 pack years as high-risk groups for lung cancer.
Most domestic guidelines generally recommend lung cancer screening for people with a history of smoking ≥ 20 pack years
.

A Meta-analysis of 19 cohort studies [8] showed that the risk of lung cancer in smokers and the risk of death were 13.
1 that of non-smokers.
Times (HR: 13.
1, 95%CI: 9.
90-17.
3) and 11.
5 times (HR: 11.
5, 95%CI: 8.
21-16.
1); the risk of lung cancer and death risk of former smokers were 4.
06 times that of non-smokers ( HR: 4.
06, 95%CI: 3.
13-5.
26) and 4.
10 times (HR: 4.
10, 95%CI: 3.
14-5.
36)
.

Data from another study [9] showed that smoking <15 cigarettes/d, 15-24 The risk of lung cancer for people with a dose/day and ≥25 tubes/d was 1.
90 times (RR: 1.
90, 95%CI: 1.
72-2.
10) and 2.
68 times (OR: 2.
68, 95%CI: 2.
49-2.
89) that of non-smokers, respectively ) And 3.
59 times (RR: 3.
59, 95% CI: 3.
22-3.
99), and the risk of disease is positively correlated with smoking intensity (P<0.
0001), that is, the longer the smoking history, the greater the smoking intensity, and the greater the risk of lung cancer High
.

Table 1 Summary of definitions of high-risk groups of lung cancer in domestic and foreign guidelines The high-risk factors of lung cancer, screening recommendations, etc.
were clearly and carefully explained
.

The "Guide" clearly pointed out that high-risk factors for lung cancer include: smoking, second-hand smoke exposure; history of chronic obstructive pulmonary disease (COPD); family history of lung cancer (first degree relative, FDR); asbestos, radon, In addition to exposure to beryllium, chromium, cadmium, nickel, silicon, soot and soot, genetic factors also play an important role in the occurrence and development of lung cancer
.

While clarifying the risk factors of lung cancer, the "Guide" also explains the protective factors of lung cancer
.

The "Guide" emphasizes that reasonable physical exercise and intake of fresh vegetables and fruits are protective factors for lung cancer
.

Studies have shown that exercise can reduce the risk of lung cancer by 25.
0%.
People with high intake of fruits and vegetables have a 14.
0% lower risk of lung cancer than those with low intake
.

The "Guide" recommends screening for people aged 50-74 who have any of the following: (A) Smoking: smoking package years ≥ 30 package years, including smoking package years ≥ 30 package years, but insufficient smoking cessation 15 years; (B) Passive smoking: living with smokers or working in the same room for ≥20 years; (C) suffering from COPD; (D) having occupational exposure history (asbestos, radon, beryllium, chromium, cadmium, nickel, silicon, etc.
) Soot and soot) for at least 1 year; (E) A first-degree relative was diagnosed with lung cancer
.

Figure 2 Lung cancer screening process.
It is worth noting that the "Guide" for the age and smoking history of the lung cancer screening population is not consistent with the general domestic "consensus", but is more in line with the standards of foreign guidelines.
, But this can't make us take it lightly
.

In particular, the problem of second-hand smoke in China is serious.
The "Guide" emphasizes that people who have smoked passively for more than 20 years should also be screened for lung cancer
.

The chance of early-stage lung cancer being cured is very large, so lung cancer screening is very important for the treatment of lung cancer
.

Lung cancer may be far away from us, or very close to us.
What we can do is "prevent the slightest failure" and suppress the possible risk of cancer in the infancy! Reference: [1]Evaluation of Population-Level Changes Associated With the 2021 US Preventive Services Task Force Lung Cancer Screening Recommendations in Community-Based Health Care Systems https://jamanetwork.
com/journals/jamanetworkopen/fullarticle/2784816[2] Screening for Lung Cancer With Low-Dose Computed Tomography Updated Evidence Report and Systematic Review for the US Preventive Services Task Force https://jamanetwork.
com/journals/jama/fullarticle/2777242[3]Characteristics of new solid nodules detected in incidence screening rounds of low-dose CT lung cancer screening:the NELSON study https://thorax.
bmj.
com/content/73/8/741[4]NCCN Guidelines for Patients.
Lung Cancer Screening,2020 https:// .
org/patients/guidelines/content/PDF/lung_screening-patient.
pdf[5]Lung Cancer Screening,Version 1.
2021,