Lung cancer screening

Five-year survival rates for lung cancer are only 22.9%, partly because most patients have advanced stage lung cancer and initial diagnosis.

Early detection of lung cancer is important to decrease mortality rates.Cancer screening is inherently inefficient due to the low prevalence of disease.

In high risk groups such as cigarette smokers, only a small proportion of individuals will be diagnosed with lung cancer.

False positive screens have occurred and as many as 39% of NLST trial participates who had low dose CT examinations.

Low-dose CT scans of the chest screening select patients who are at higher risk for lung cancer decrease mortality.

based on racially and ethnically diverse populations based cohortstudies USPSTF guidelines for lung cancer screening, still induce racial and ethnic disparities, and it is suggested a risk based lung cancer screening using a validated risk prediction model may help reduce racial and ethnic disparities in lung cancer screening.

Chest radiography is not recommended for lung cancer screening.

Screening has potential harms including: false positive results, radiation exposure, overdiagnosis, incidental findings, complications for invasive procedures which include needle biopsy, bronchoscopy, and thoracic surgical procedures.

Mayo Clinic screening trial 90% of peripheral carcinomas and 75% of perihilar carcinomas were visible in retrospect on older chest X-rays.

Trials evaluating chest radiographs and sputum cytology as screening modalities fail to show a decrease in lung cancer mortality in the screened groups.

Trials evaluating chest radiographs every quarter in high risk patients leads to the detection of resectable malignancy in only 29% of cases of lung cancer.

Chest x-ray is not recommended for lung cancer screening.

Early randomized controlled involving chest x-rays and sputum cytology screening found slightly more lung cancers, smaller tumors, and more stage I tumors, but the detection of a larger number of advanced lung cancers or a reduction in lung cancer deaths.

By using chest radiographs for screening the majority of lung cancer less than 2 cm. in diameter will be missed.

By spiral CT can identify lesions with a median diameter of 1.5 cm. or less with approximately 80% Stage IA and a 5-year survival of 78%. This is compared to current medical practice where only 15-20% are Stage IA.

Spiral CT has a high sensitivity but poor specificity with one trial detecting more than 70% of participants while fewer than 4% had lung cancer.

Early Lung Cancer Action Project (ELCAP)-studied smokers with annual screening with spiral computed tomography, and found that 80% of those detected to have cancer had stage I disease.

Early Lung Cancer Action Project (ELCAP)-revealed that among 484 patients diagnosed with lung cancer 10-year survival for lung cancer specific disease was 80%.

Early Lung Cancer Action Project (ELCAP)-among 412 participants with clinical stage I disease the estimated 10-year survival was 88%, and of those who underwent surgical resection within 1 month the rate was 92%.

The National Lung Screening Trial (NLST) screened more than 53,454 current or former smokers aged 55-74 years with spiral CT scans of the chest: 20% fewer lung cancer deaths among screened participants then those screened with chest x-rays, and all cause mortality with 7% lower in the group screened by the helical CT.

The rate of positive results was higher with low dow dose CT screening than with chest x-rays by more than 3 times, but was associated with a higher rate of false positive studies(The National Lung Screening Trial Research Team).

Results of the National Lung Screening Trial (NLST) showed that annual low-dose CT screening reduces lung cancer mortality in high risk patients followed for up to 5 years after the last annual screening by about 15-20% relative to a control group receiving chest radiographs.

Low-does CT screening for lung cancer has demonstrated early detection and reduced relative all-cause mortality by 6.7% and relative lung cancer-specific mortality by 20% in appropriately selected patients between age 55 and 80 years, 30 or more pack year smoking history, currently smokin or quit within 15 years, and life expectancy not limited by another end stage disease (Aberle DR).

US Preventive Services Task Force study showed CT screening can reduce lung cancer specific mortality by 62 events for 100,000 person-years and is recommended by the US Preventive Services Task Force for patients age 55-80 years who have a 30 year pack smoking history and currently smoke or quit within the last 15 years.

In 2021 the USPSTF extended screening guidelines to include individuals age 50-80 with a 20 pack year smoking history within the past 15 years.

Among high-risk persons, lung cancer mortality was significantly lower among those who underwent volume CT screening than among those who underwent no screening (de Kooning HJ).

Touch-billion lung cancer screening study: 18 years follow up ling cancer mortality was lower in the screening group than in the control group among men 24% and among women by 33%.

Over 40% of lung cancer‘s among former smokers have been shown to be diagnosed with in 15 years after smoking  cessation.
The seventh leading cause of cancer related deaths in the United States is lung cancer in never smokers, accounting for 20,000 US deaths each year.

The above findings suggest that a two-year interval between screenings is safe and effective.

The USPSTF recommendation is low-dose CT screening for individuals age 50 to 80 who had a 20 pack year smoking history and who currently smoked or quit in the past 15 years.

Currently less than 6% of eligible Americans undergo annual low-dose CT lung cancer screening.

Leave a Reply

Your email address will not be published. Required fields are marked *