Definition and Overview

Also known as pulmonary carcinoma or carcinoma of the lung, lung cancer is a condition characterised by the presence of a malignant tumour in the tissues of the lungs. There are two main types of lung cancer: SCLC or small-cell lung carcinoma, and NSCLC or non-small-cell lung carcinoma. One subtype of NSCLC is called lung adenocarcinoma, which accounts for 40% of all lung cancer cases.

The majority of lung cancer cases are caused by long-term tobacco smoking. But there are also cases where individuals who did not smoke (but were exposed to tobacco smoke) developed the disease. Research shows that the development of lung cancer can also be influenced by genetic factors and exposure to various chemicals and air pollution.

Lung cancer is one of the leading causes of death in both male and female population in the world and is one of the most fatal forms of cancer. In the United States, 16.8% of lung cancer patients live for around five years after being diagnosed with the condition. For countries in the developing world, lung cancer survival rate is generally low. Official figures confirm that lung cancer kills around a million and a half individuals per year.

Pulmonary carcinoma can be categorised into “stages,” which refers to the extent of the spread of cancerous tissues. Treatments of lung cancer include surgery, medication (including chemotherapy), and radiation therapy.

Lung Cancer Causes

The development and occurrence of lung cancer are attributed to different factors, with cigarette smoking identified as the major cause. Research shows that cigarette smoke has over seventy carcinogens or substances that can cause cancer. In the developed world, an overwhelming number of lung cancer deaths (an estimated ninety percent of male patients and seventy percent of female patients) were caused by cigarette smoking. Aside from smoking cigarettes, passive smoking, or second-hand cigarette smoke also results in lung cancer. In some studies, it is discovered that passive smoking is more dangerous than direct smoking.

A study published in 2014 reveals that people who smoke cannabis or marijuana are also at high risk of lung cancer. Like cigarette smoke, marijuana smoke also has many carcinogens. Another study, however, seems to suggest that heavy marijuana smoking can cause this risk, but individuals who smoke cannabis lightly or moderately are not at a significant risk.

Radon gas is another substance that can cause lung cancer. This odourless and colourless gas is a product of radium breakdown. It ionizes genetic material, which can lead to mutations causing cancer cells to develop. In the United States, radon gas is the second leading cause of lung cancer, right after cigarette smoke. Asbestos, a substance that was used in many insulation and construction materials in the past, is also a common cause of lung cancer.

Research shows that exposure to air pollution can increase an individual’s risk of developing lung cancer. Air pollution can come in the form of nitrogen dioxide, traffic exhaust fumes, and fumes from burning charcoal, wood, crop residue, or animal.

An individual’s occupation can also increase the risk of lung cancer. For example, exposure to several metals including aluminium, arsenic, melted iron, nickel, cadmium, beryllium, and chromium can increase the risk of lung cancer because of carcinogenic fumes. People who work in industries that produce rubber and glass products are also at risk of developing this disease.

Finally, genetics can also play a significant role in the development of lung cancer. Research shows that individuals who have relatives with the disease are twice more likely to develop lung cancer.

Lung Cancer Symptoms

Symptoms of lung cancer can include:

  • Coughing

  • Shortness of breath and wheezing

  • Significant weight loss

  • Clubbed fingernails

  • Tiring too easily and fatigue

  • Chest pain

  • Pain in the bones

  • Difficulty in swallowing

  • Obstruction of the superior vena cava or the large vein responsible for carrying blood to the heart

  • Breathing difficulties

  • Metastatic lung cancer can cause neurological symptoms, such as weakness in the limbs, convulsions, headaches, and fainting.

Who to See

Most of the time, the symptoms listed above do not readily point to lung cancer. In fact, the majority of cases are only discovered when patients undergo chest radiography. Patients who are suffering from lung cancer typically consult with two or more doctors. An oncologist or a cancer specialist is at the top of the list. Major hospitals have their own cancer departments, with at least one oncologist specialising in lung cancer. A radiologist can also come in handy, as well as a thoracic surgeon who performs the procedures necessary to remove the cancerous growths in the patient’s lungs.

Types of Treatments Available

Before any type of treatment is prescribed, patients are assessed for lung cancer staging. This procedure determines the extent to which lung cancer has spread to the body. It involves the assessment of the tumour and whether or not the cancer has already metastasized to nearby lymph nodes and other organs. The lung cancer stage is determined using various tests including bone, CT, and PET scans, blood tests, and x-rays. Below are lung cancer stages:

  • Stage I – Localised cancer (confined to the lung)

  • Stage II – Cancer cells may have already spread to nearby lymph nodes

  • Stage III – Locally advanced lung cancer

  • Stage IV – Stage 4 lung cancer is the most advanced stage of the condition. Tumors under this category are considered inoperable and most of the time, no longer curable.

Treatments and management methods for lung cancer depend on the severity of the condition and the health of the patient. Common lung cancer treatments include chemotherapy, surgery, radiation therapy, and palliative care.

  • Surgery involves the removal of lung lobes, typically prescribed for patients suffering from the early stages of NSCLC. The surgical procedure is known as lobectomy.

  • Chemotherapy - This treatment is prescribed based on the type of the tumour discovered. SCLC is typically treated with a combination of radiation therapy and chemotherapy, while NSCLC sufferers are given chemotherapy alone as a form of first-line treatment.

  • Radiotherapy is often prescribed with chemotherapy, usually for patients who are not healthy enough for surgical treatment.

  • Palliative care is a supplementary or complementary treatment for patients undergoing chemotherapy.


  • Lung Cancer Organization –

  • National Cancer Institute –

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