Lung cancer is a serious disease that affects up to one in 12 Canadian men each year.1 It is the leading cause of cancer-related mortality in Canada and the United States and is responsible for more deaths than breast, colorectal and prostate cancer combined.1,2 Cigarette smoking is by far the most common risk factor for developing lung cancer and quitting is the best thing you can do to reduce your risk. 2

Hearing the word cancer can be overwhelming and it is important to know there are many non-malignant, or non-cancerous, conditions that can mimic cancer. Since the symptoms can be similar, specialized testing is often needed to differentiate the cause. If you or someone you know has been diagnosed with lung cancer it is important to know there are different types. They can vary in terms of severity of disease, which has a large impact on how people respond to treatment.

What is Lung Cancer?

Cancer occurs when cells in the body behave abnormally, causing uncontrolled growth and potentially spreading through the body. Primary lung cancer, which is cancer that starts out in the lungs, is categorized based on the originating cell type. The major types are usually divided into non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Other types of cancer can also occur in the lungs such as lymphoma (originating from the lymph nodes), metastatic disease (cancer spread from other places) and mesothelioma. Mesothelioma is a type of cancer that develops in the lining of the lung and is strongly associated with asbestos exposure. The severity and extent of lung cancer is determined by the stage of cancer. Staging is based on the size and location of the cancer and if it has spread to lymph nodes (small glands found throughout the body that are part of the immune system) or outside of the lungs.3,4

Statistics

Lung cancer hugely impacts the Canadian population. In 2016, about 28,400 Canadians were diagnosed with lung cancer.1 In Canada, lung cancer is the leading cause of cancer-related deaths and causes more deaths than the next three most common cancer types combined.1 Lung cancer is typically more common in men. Smoking rates in men have decreased over the past 40 years and subsequently so have lung-cancer rates.5,6 However, lung cancer rates and mortality in females have remained stable over the last decade.1 These patterns demonstrate how the rates and deaths of lung cancer mirror smoking habits of the population.

Risk Factors

Cigarette smoking is by far the most common risk factor for developing lung cancer.7 Smoking cigarettes increases a person’s risk of developing lung cancer by 10 to 30 times compared to a non smoker. Up to 85 percent of lung cancer deaths are caused by smoking.2 Importantly, all types of tobacco products (herbal cigarettes, cigars, pipes, chewing tobacco) can cause cancer in the mouth, throat, and lungs. Second hand-smoke is also associated with an increased risk for lung cancer and it is important to reduce you and your family’s exposure.8

Quitting smoking is the most important thing a person can do to reduce their risk of lung cancer. Within 10 years of quitting smoking the risk for lung cancer-related death decreases by 30 to 50 percent. Regardless of how long a person has smoked, working towards complete abstinence is important. Even in people with a diagnosis of lung cancer, quitting smoking reduces their risk for death.9

Additional Risk Factors

There are several other risk factors for lung cancer. In people who smoke, some of these risk factors synergistically increase the risk for lung cancer. This means that the risk increases more than just adding the risk from each factor together.2

  • Smoking tobacco products
  • Radiation in the home from radon, which is a radioactive gas that occurs naturally when the uranium in soil and rock breaks down
  • Occupational or environmental exposure to such things as radiation or indoor cooking using wood or coal
  • Asbestos exposure
  • Age
  • Family history

Screening

Screening refers to the testing for a condition or disease in a person who does not have any symptoms or signs of the disease. The purpose of screening is to find a disease early so that treatment can be given to prevent the disease from worsening. In people aged 55-74 who are current or former smokers in the past 15 years, and have smoked one pack per day for at least 30 years or two packs a day for 15 years, there is research showing that computed tomography (CT or CAT scans) of the chest once a year for three years can reduce the risk of dying from lung cancer. It is important to know that most people who are screened will not have lung cancer and the screening itself can have risks. These include radiation exposure, findings on CT which are not lung cancer, or complications from follow-up testing. A formal screening program has not yet been established in Canada. It is worthwhile talking to your doctor if you have questions about lung cancer screening.10

Symptoms

Although very early lung cancer may not cause any symptoms, many people with the disease will develop one or more symptoms. The same symptoms that occur with lung cancer occur with other, more common conditions.  If you have any concerns you should talk with your doctor.11Symptoms include:

  • A cough that won’t go away
  • Coughing up blood
  • Shortness of breath or wheezing
  • Chest pain that is worse with coughing or deep breathing
  • Voice hoarseness
  • Unexplained weight loss or loss of appetite
  • Fatigue
  • Severe shoulder pain
  • Drooping or weakness of one eyelid and a small pupil
  • Headache and swelling of face, arms, or neck

Diagnosis

If you or your doctor is concerned about lung cancer, he or she will take a detailed medical history and perform an examination. Based on this information your doctor will decide what further testing is required. An assessment for possible lung cancer may require a combination of bloodwork, chest X-rays, or a CT scan. Depending on the results you may be referred to a respirologist or thoracic surgeon for further testing. A tissue sample, called a biopsy, may be needed. Biopsy samples can be obtained in several ways including bronchoscopy (video examination of the inside of the lungs), fine needle aspirate (FNA), or a surgical procedure (mediastinoscopy). Further testing may be required depending on the results of the initial investigations.

Treatment

Treatment for lung cancer is dependent on the type and stage of cancer as well as a person’s overall health. Treatment may involve surgery, chemotherapy, and/or radiation therapy. Treatment may be provided by a cancer specialist, called an oncologist, or a thoracic surgeon. More information can be found on the Canadian Cancer Society website.

References

1. Canadian Cancer Society’s Advisory Committee on Cancer Statistics. (2016). Canadian Cancer Statistics 2016. Toronto, ON: Canadian Cancer Society.

2. National Cancer Institute. (2016, F.L.C.P.P.H.P.V.  January 22, 2017]; Available from: http://www.cancer.gov/types/lung/hp/lung-prevention-pdq.

3. Spira, A. and D.S. Ettinger, Multidisciplinary management of lung cancer. N Engl J Med, 2004. 350(4): p. 379-92.

4. Robinson, B.W. and R.A. Lake, Advances in malignant mesothelioma. N Engl J Med, 2005. 353(15): p. 1591-603.

5. American Cancer Society: Cancer Facts and Figures 2016. Atlanta, Ga: American Cancer Society, 2016.

6. Edwards, B.K., et al., Annual report to the nation on the status of cancer, 1975-2002, featuring population-based trends in cancer treatment. J Natl Cancer Inst, 2005. 97(19): p. 1407-27.7. Alberg, A.J., et al., Epidemiology of lung cancer: ACCP evidence-based clinical practice guidelines (2nd edition). Chest, 2007. 132(3 Suppl): p. 29S-55S.

8. Hackshaw, A.K., M.R. Law, and N.J. Wald, The accumulated evidence on lung cancer and environmental tobacco smoke. BMJ, 1997. 315(7114): p. 980-8.

9. Parsons, A., et al., Influence of smoking cessation after diagnosis of early stage lung cancer on prognosis: systematic review of observational studies with meta-analysis. BMJ, 2010. 340: p. b5569.

10. Canadian Task Force on Preventive Health, C., et al., Recommendations on screening for lung cancer. CMAJ, 2016. 188(6): p. 425-32.

11. Canadian Cancer Society. Lung Cancer. Accessed January 23, h.w.c.c.e.c.-i.c.-t.l.l.-c.r.o.