Can lung cancer be detected early?

In the 20th century, the world population began to experience rising mortality from lung cancer caused by chronic exposure to tobacco smoke. This epidemic of lung cancer deaths is now receding in some nations where tobacco control has reduced smoking, but it is rapidly rising in others, says Dr Unmil Shah, Pulmonologist at Global Hospitals, Mumbai

L-C

Although, lung cancer is the third most common cancer diagnosed among men and women (after prostate cancer and breast cancer), the annual burden of this disease is larger than that of any other cancer. It accounts for 13 per cent of all new cancer cases and 19 per cent of cancer related deaths worldwide.

In India, lung cancer constitutes 6.9 per cent of all new cancer cases and 9.3 per cent of all cancer related deaths in both sexes. It is the commonest cancer and cause of cancer related mortality in men, with the highest reported incidences from Mizoram in both males and females. Smoking tobacco, both cigarettes and beedis, is the principal risk factor for causation of lung cancer in Indian men. However, among Indian women, the association with smoking is not strong, suggesting that there could be other risk factors besides smoking.

Dr Unmil Shah, Pulmonologist at Global Hospitals, Mumbai
Dr Unmil Shah, Pulmonologist at Global Hospitals, Mumbai

Early warning signs:

  • A cough that does not go away or gets worse
  • Coughing up blood or rust-coloured sputum (spit or phlegm)
  • Chest pain that is often worse with deep breathing,
  • Infections like bronchitis and pneumonia that don’t go away or keep coming back
  • New onset of wheezing
  • Hoarseness of voice

But can we detect lung cancer much early before these symptoms set in?

Screening is the use of tests or exams to find a disease in people who don’t have symptoms. Doctors have looked for many years for a good screening test for lung cancer, but only in recent years has a study shown that a test known as a low dose CT (LDCT) scan can help lower the risk of dying from this disease. Low-dose CT of the chest uses lower amounts of radiation than a standard chest CT and does not require the use of intravenous (IV) contrast dye.

Guidelines recommend annual lung cancer screening with LDCT for adults aged 55 to 79 years with a 30–pack-year history of smoking, and annual screening beginning at age 50 for adults with a 20–pack-year history who have an additional cumulative risk of developing lung cancer of 5% or greater over the following 5 years.

  • Benefit: Screening with LDCT has been shown to substantially reduce the risk of dying from lung cancer.
  • Limitations: LDCT will not detect all lung cancers or all lung cancers early, and not all patients who have a lung cancer detected by LDCT will avoid death from lung cancer.
  • Smoking cessation counselling constitutes a high priority for clinical attention for patients who are currently smoking. Current smokers should be informed of their continuing risk of lung cancer, and referred to smoking cessation programs.

Screening should not be viewed as an alternative to smoking cessation. Hence, the old adage Prevention is better than cure’.

The author is the Pulmonologist at Global Hospitals Mumbai