Types of Lung Cancer: Knowing the Differences and Treatment Options

Dr. Nandish Jeevangi, Consultant Medical Oncology, HCG Cancer Centre, Kalaburagi 

Lung cancer is the third riskiest form of cancer. This cancer has affected millions of people around the world.  Lung cancer is caused due to abnormal cell division in the lungs. The mutated or damaged cells, when divide themselves abnormally, form masses or tumors of tissue which hinder the functioning of the lungs. Lung cancer often begins in the airway, bronchi or bronchioles or in the small air sacs, alveoli.  Lung cancer consists of two major types: Non-Small Cell Lung Cancer (NSCLC) and Small Cell Lung Cancer (SCLC). Each of these have their own subtypes and the treatment options differ for both.

Non-Small Cell Lung Cancer (NSCLC):

 Non-Small Cell Lung Cancer constitutes for about 85% of the total cases of lung cancer reported. This form of lung cancer consists of several subtypes. Adenocarcinoma often originates in the outer regions of the lung and is the most common type of NSCLC. Smoking has been linked to the development of squamous cell carcinoma, which often starts in the bigger airways. A less frequent variant of lung cancer called the large cell carcinoma can appear anywhere in the lungs.

Diagnosis:

Through biopsies, molecular testing, and imaging studies we can diagnose NSCLC. Cancer staging establishes the extent of the disease’s spread and directs medical decisions. The selection of treatment depends on the stage, which ranges from I (localized) to IV (advanced).

Treatment Options for NSCLC:

 Immunotherapy: This approach has shown promising results in extending survival as it stimulates the immune system directly and destroys the cancer results. The results have been noticed in a few NSCLC patients.

• Chemotherapy: Cancer cells and other cells that divide quickly are killed by systemic chemotherapy. It is frequently recommended in the latter stages or in conjunction with other therapies.
• Surgery: NSCLC in the very early stages can be treated by surgery. The tumor and surrounding tissues can be removed if the cancer has not spread extensively into the lungs and damaged them.
• Radiation Therapy: This approach can be used in combination with chemotherapy and surgery or as the primary treatment option. This method uses high beam rays to kill the cancer cells and prevent the spread of cancer.
• Targeted Therapy: Certain Cases of NSCLC have specific genetic mutations and it becomes difficult to treat them. To treat them, precise medications are prescribed. These drugs inhibit the growth and spread of cancer cells.

Small Cell Lung Cancer (SCLC):

Small Cell Lung Cancer is more aggressive and difficult to treat unlike NSCLC. This form of lung cancer begins as a small tumor in the lungs and spreads rapidly to other parts of the body during its initial stages of development.

Specific subtypes of SCLC include small cell carcinoma also known as “oat cell carcinoma” and combined small cell carcinoma.

This form of lung cancer has two distinct stages namely, limited, and extensive. While the limited stage SCLC is confined to one lung and nearby lymph nodes, the extensive stage SCLC spreads to other parts of the lung and distant sites.

Diagnosis:

Similar to NSCLC, SCLC can be diagnosed through biopsies, molecular testing, and imaging studies and also through series of physical examinations, CT scans, X-rays and medical history evaluation.

Treatment Options for SCLC: 

• Immunotherapy: This approach is compared to be less effective in the case of SCLC. Immunotherapy can be used to improve the response of immune system in some cases.
• Chemotherapy: Due to its aggressive nature and rapid growth, chemotherapy is considered a standard treatment option for SCLC. Combination of drugs are used from different angles to attack and kill the cancer cells.
• Radiation Therapy: Radiation therapy is combined with chemotherapy to target the primary tumor and any other potential spread to nearby lymph nodes only in limited stage SCLC.
• Prophylactic Cranial Irradiation (PCI): PCI may be suggested for patients with extensive-stage SCLC who react well to early therapy to stop the cancer from spreading to the brain.

Prevention:

Any type of lung cancer can be prevented by adopting lifestyle changes, environmental awareness, regular health checkups and being aware of one’s own body.

1. Genetic counseling: One of the most important reasons for incidence in lung cancer is family history. Certain individuals have higher genetic predisposition to this disease. In such cases, consider opting for genetic counseling to assess and prevent the risk factor of suffering from this disease.

2. Cease Smoking: Smoking causes 85% of all the lung cancer cases. Tobacco causes damage to the lung cells and causes genetic mutations that lead to cancer growth. Quitting smoking is the first step any individual can take to prevent lung cancer. Instead of smoking, one can utilize nicotine replacement therapies to quit smoking one step at a time.

3. Early detection: Regular health checkups and screening are significant and help in detecting lung cancer. For individuals who smoke on a regular basis or have any other risk factors, a low dose CT scan is done to detect abnormalities before the symptoms manifest.

4. Limiting Alcohol Consumption: Consumption of alcohol in excess can weaken the immune system which in turn leads to inflammation and increases the chance of cancer. If consuming alcohol, do so in recommended quantity.

5. Occupational Hazards: Certain occupations involve working with heavy metals, chemicals, and asbestos. This in turn increases the risk of lung cancer in individuals working there. One can prevent the risk by adhering to safety protocols, being vigilant about occupational hazards and wearing protective gear.

Each subtype of lung cancer requires a specific strategy to treatment because it is a complicated disease with several subtypes. The likelihood of a positive outcome is significantly increased by early diagnosis, precise staging, and tailored treatment approaches.