You are here

What is Lung Cancer? | ALK Testing

What is lung cancer?

Lung cancer is the most common type of cancer, with 1.8 million new cases in 2012 worldwide.1 There are two main types of lung cancer ─ small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) – which are treated very differently.2

SCLC accounts for 10–15% of lung cancers, and is named for the small size of the cells seen under the microscope. It is usually caused by smoking, and tends to spread quite early on.2

NSCLC is the most common type of lung cancer, making up the remaining 85–90% of cases. There are three main types of NSCLC – adenocarcinoma (40%), squamous cell carcinoma (25–30%) and large cell carcinoma (10–15%). They look different under the microscope, but are grouped together because doctors treat them in a similar way.2

  • Adenocarcinoma develops from the mucus-producing cells in the lining of the airways, usually in the peripheral regions of the lung, and is generally slow-growing.2
  • Squamous cell carcinoma arises in the cells covering the surface of the airways. These tumours are often found in the central areas of the lung.2
  • Large cell carcinoma can develop in any area of the lung. It tends to grow and spread quickly.2

What causes lung cancer?

The most important risk factors for lung cancer are smoking and older age.3 However, lung cancer can affect anyone. The adenocarcinoma form of NSCLC is the most frequent type of lung cancer found in people who don’t smoke, and is also more likely to affect women and younger people than other types of lung cancer.2

How can lung cancer be treated?

Doctors use many different treatments for lung cancer, often in combination. There’s no ‘one size fits all’ approach, and it’s important to make a treatment plan with your doctor that is individualised for you. You should always feel free to ask questions and discuss your concerns.

Surgery may be used to remove tumours which are found at an early stage. Surgery may be combined with other treatments to try and reduce the chances of the tumour recurring.2

Radiotherapy uses high-energy rays to kill cancer cells. External beam radiotherapy directs radiation on the tumour from outside the body. It is more commonly used for lung cancer than internal radiotherapy (also known as brachytherapy), which involves radioactive material being placed within or nearby the tumour.2

Chemotherapy is treatment with anticancer drugs, either injected into a vein or taken orally. These drugs enter the bloodstream and can kill cancer cells anywhere in the body, which is useful for cancers that have spread. Chemotherapy can be given before surgery to try and shrink a tumour (neoadjuvant), after surgery to prevent the tumour coming back (adjuvant) or as the main treatment for cancer that has spread.2

Targeted therapies are drugs which work in a different way from standard chemotherapy drugs. They are designed to target and block specific genetic and molecular changes which drive the growth and survival of cancer cells.2

At least 10 genetic changes have been identified that play a role in NSCLC.4,5 Currently, there are approved drugs available to specifically treat two of these – ALK and EGFR. ALK abnormalities are found in around 5% of NSCLC and EGFR abnormalities in around 15%.5 Treatments targeting NSCLC with other genetic changes are currently being developed and tested in clinical trials.4,5

Known genetic changes in NSCLC5

Known genetic changes in NSCLC

How do I know whether targeted therapies are an option for me?

It’s important to identify patients whose tumours have certain genetic changes, as they could benefit from targeted therapies. Testing for genetic changes is called molecular profiling, and is carried out on samples of tumour tissue (known as biopsy specimens). The test results can provide your doctor with more information about your tumour, which may help to guide your treatment plan or determine whether you are eligible for clinical trials.4,5 If your tumour hasn’t been tested, it’s important to talk to your doctor and ask if molecular profiling may be right for you.

Overview of molecular profiling

Overview of lung cancer molecular profiling

How do doctors decide to treat with targeted therapies?

Lung cancer targeted therapy decision

References

  1. Ferlay J, Soerjomataram I, Ervik M, et al. GLOBOCAN 2012 v1.0, Cancer Incidence and Mortality Worldwide: IARC CancerBase No. 11. Lyon, France: International Agency for Research on Cancer; 2013. http://globocan.iarc.fr. Accessed 2 February 2016
  2. American Cancer Society, 2014. Lung Cancer (Non-Small Cell). http://www.cancer.org/cancer/lungcancer-non-smallcell/. Accessed 2 February 2016
  3. National Cancer Institute, 2015. Lung Cancer Prevention – for health professionals (PDQ). http://www.cancer.gov/types/lung/hp/lung-prevention-pdq. Accessed 2 February 2016
  4. Thomas A, Rajan A, Lopez-Chavez A, et al. From targets to targeted therapies and molecular profiling in non-small cell lung carcinoma. Ann Oncol 2013;24:577─585
  5. Korpanty GJ, Graham DM, Vincent MD, Leighl NB. Biomarkers that currently affect clinical practice in lung cancer: EGFR, ALK, MET, ROS-1, and KRAS. Front Oncol 2014;4:204

RESOURCES