Screening of Small cell lung cancer

The screening procedure helps detect small cell lung cancer at the initial stage while determining its possibility of survival benefit ​1,2​. The primary aim of screening is to reduce the death rate of individuals occurring due to small cell lung cancer, eliminate the deaths from cancer, and reduce the number of individuals prone to develop the risk of small cell lung cancer. 

The National Lung Screening Trial (NLST) has shown the efficacy of screening with low-dose CT (LDCT) imaging when compared with the chest radiography (CXR) that showed a reduction in the death rate ​3,4​. Several lung screening programmes are available for individuals at increased risk of developing small cell lung cancer. These programs have enabled the doctors to diagnose the initial stage of the disease, showing the treatment’s efficacy ​5​. The doctors have followed the screening guidelines that involve annual lung cancer testing among individuals from 55-80 years who are observed with at least 30-pack-year smoking history. It represents that such individuals have smoked the equivalent of 1 pack of cigarettes a day for 30 years. The individuals who currently smoke or have quit their smoking habits within the last 15 years should be screened for small cell lung cancer. 

Some of the organisations have been recommended to screen the individuals belonging to the age group of 50 or even older possessing a 20-pack-year smoking history showing additional risk factors for developing small cell lung cancer involving exposure to secondhand smoke or chemicals. The researchers have mainly determined the use of low-dose CT scans for lung cancer screening in the 1990s. Depending upon this work’s work, the scanning techniques have been mostly preferred for detecting small cell lung cancer. CT screening is not recommended to the individuals who have smoked for less than 30 pack-years belonging to the age group of 55 years or older than 74, individuals who have quit smoking more than 15 years ago or suffering from any severe concern affecting the cancer treatment or reducing the life span of the individuals. Some of the effective screening techniques have been represented below:

  • Low-dose CT scans (LDCT): It mainly utilise x-rays and computers to create three-dimensional cross-sectional images of the body. Low-dose radiation has been integrated into the LDCT screening technique that produces a detailed picture of the areas within the body using an x-ray scanning machine that scans the body in the spiral path. Hence, it is also known as spiral scan or helical scan. The CT scans have been found to give better results for detecting early stages of small cell lung cancer compared to conventional chest x-rays. The low-dose CT scans can produce one-fifth of the radiation dose of the standard CT scan, which helps limit radiation exposure among the individuals who require annual screening. The experts have detected the suspicious growth of cells within the lungs on screening the CT scans, mainly among the individuals who have the habit of smoking. Most of the time, the detection does not reveal cancer. Instead, they offer the development of larger blood vessels, small scars, lymph nodes, small immune system glands that are capable of trapping foreign invaders like viruses and bacteria. The lymph nodes become enlarged due to several reasons involving the infection.

If the abnormal growth of the cells is observed within the lungs, the follow-up CT scans are used for confirming the findings that show no alterations with time. The changing growth of cells proves to be cancerous and requires more appropriate testing before the diagnosis confirmation.

The screening with LDCT once every year for three consecutive years has shown efficacy in determining the initial stage of small cell lung cancer and decreasing the death rate among current and former heavy smokers.   

  • Chest x-ray: It involves the x-ray of the organs and bones inside the chest region. The energy beam is produced and goes through the body and is produced in film making images of areas inside the body. 
  • Sputum cytology: It is a protocol in which a sputum (mucus that is coughed from the lungs) sample is taken and viewed under the microscope to check with the cancer cells. 

References

  1. 1.
    Cuffe S, Moua T, Summerfield R, Roberts H, Jett J, Shepherd FA. Characteristics and Outcomes of Small Cell Lung Cancer Patients Diagnosed During Two Lung Cancer Computed Tomographic Screening Programs in Heavy Smokers. Journal of Thoracic Oncology. Published online April 2011:818-822. doi:10.1097/jto.0b013e31820c2f2e
  2. 2.
    Farooqi AO, Cham M, Zhang L, et al. Lung Cancer Associated With Cystic Airspaces. American Journal of Roentgenology. Published online October 2012:781-786. doi:10.2214/ajr.11.7812
  3. 3.
    Pinsky PF, Church TR, Izmirlian G, Kramer BS. The National Lung Screening Trial: Results stratified by demographics, smoking history, and lung cancer histology. Cancer. Published online August 26, 2013:3976-3983. doi:10.1002/cncr.28326
  4. 4.
    Thomas A, Pattanayak P, Szabo E, Pinsky P. Characteristics and Outcomes of Small Cell Lung Cancer Detected by CT Screening. Chest. Published online December 2018:1284-1290. doi:10.1016/j.chest.2018.07.029
  5. 5.
    Titulaer MJ, Wirtz PW, Willems LNA, van Kralingen KW, Smitt PAES, Verschuuren JJGM. Screening for Small-Cell Lung Cancer: A Follow-Up Study of Patients With Lambert-Eaton Myasthenic Syndrome. JCO. Published online September 10, 2008:4276-4281. doi:10.1200/jco.2008.17.5133