Lung cancer – A devastating disease but early detection holds hope of cure

Lung cancer – A devastating disease but early detection holds hope of cure

A devastating disease, lung cancer is one of the most common cancers and the main causes of cancer mortality in the world. It is most commonly occurring cancer in men and the third most commonly occurring cancer in women accounting for 32% of cancer deaths in men and 20% of cancer deaths in women.It has a mortality rate that is thrice that of prostate cancer and nearly twice that of breast cancer in women.Each year, more people die of lung cancer than of colon, breast, and prostate cancers combined. In India, lung cancer constitutes around 7 per cent of all new cancer cases and around 9 per cent of all cancer related deaths.

The high mortality is a result of this cancer having no clinical signs in the early stages. Patients go to the doctor when they get symptoms, by which time the cancer is in advanced stages, and this increases the mortality rate. Lung cancer is commonly seen with increasing age especially between the ages of 50-70 years, with only ~2% reported under age of 40.Even in these older patients, the disease is often diagnosed incidentally through a scan or x-ray performed for some other indication.

While lung cancer is affected by many factors, the most important one is smoking cigarettes with the risk being 20 times higher in smokers as against non-smokers. The risk is also directly proportional to the duration, amount and manner of consumption of tobacco. Other risk factors include air pollution especially caused by fuels, occupational exposure to carcinogens such as asbestos, arsenic, and other aromatic hydrocarbons, underlying lung diseases, family history of lung cancer, nutritional factors (vitamins A, B, and C), substance abuse, and opioids consumption.

While at present, about 90% of lung cancers are caused by smoking, the proportion of non-smokers with lung cancer is expected to go up due to the effect of anti-smoking campaigns. Lung cancer in non-smokers usually occurs at an earlier age and is diagnosed at an advanced stage.

The Human Development Index (HDI), a function of quality of life, health and health facilities, economic and social security is another factor that has been found to be linked tothe incidence and mortality of lung cancer. Studies have shown that lung cancer incidence in developed countries is ~2 times higher than that of the less developed countries in any age group. This may be due to a higher aging population in most developed countries. However, even in the less developed countries, an increase in smoking cigarette and using tobacco is causing a rise in cases.

The signs and symptoms of lung cancer include a new cough that has persisted for 3 weeks or more, a changed cough, coughing up blood, a chest infection that is recurrent, stays for long and is resistant to treatment, chest pain and/or shoulder pain, shortness of breath, and hoarse voice. There may be associated weight loss or loss of appetite. The symptoms are often vague and mimic those of other conditions leading to delay in the diagnosis. This leads to the majority of cases being diagnosed after the disease has metastasised, that is, spread to distant areas.

Early detection of lung cancer, especially at the stage where the tumor is still localized has good survival outcomes with 5-year survival rate going up to 75% and many patients being cured. However, for patients with advanced disease and metastases, the 5-year survival rate is only around 4%. This goes to show that it is important to do lung cancer screening so that tumors can be detected early. Screening is especially essential in high risk cases like smokers above the age of 55. The knowledge of high-risk behaviors, including population aging, smoking, and air pollution can lead to developing effective programs for early detection and fighting this disease.

Tests to diagnose lung cancer include imaging tests like an X-ray and a CT scan, sputum cytology and tissue biopsy. Once the diagnosis is made, the state of the cancer is determined using CT scans, magnetic resonance imaging (MRI), positron emission tomography (PET) and bone scans.This indicates the extent of the cancer and helps in deciding on the further management of the disease.

Based on the stage of cancer, the course of treatment is decided. This may include surgery, chemotherapy, radiation therapy or targeted drug therapy either singly or in combination.Targeted therapies with small molecule drugs or monoclonal antibodies (mAb) are the latest available drugs to fight lung cancer. Targeted therapy uses drugs or other substances to identify and attack specific types of cancer cells with less harm to normal cells. Targeted therapy may have fewer side effects than other types of cancer treatment. With the discovery that lung cancer has several sub-types, each characterized by mutated genes and abnormal proteins, specific targeted therapies can be used tokeep specific types of lung cancers in check. So let us stop the devastation caused by lung cancer through regular screening for early detection and proper treatment and management!