What Is Lung Cancer? | Types of Lung Cancer

Overview

Lung cancer is a type of cancer that originates in the lungs, two spongy organs located in the chest cavity. These vital organs take in oxygen and expel carbon dioxide, allowing the body to function correctly. When lung cells mutate and grow uncontrollably, they can form malignant tumours, leading to lung cancer.

This aggressive disease is one of the most prevalent forms of cancer worldwide, affecting millions of individuals each year. It is a complicated condition that can manifest in various forms and stages of lung cancer, making early detection and proper treatment crucial for improving outcomes.

Lung cancer can be classified into 2 main types: Non Small Cell Lung Cancer (NSCLC) (most common type of lung cancer) & Small Cell lung cancer (SCLC), former accounting for 85% of all lung cancer cases, while latter constitutes the remaining 15%. Each type exhibits distinct characteristics, growth patterns, and treatment approaches.

Understanding lung cancer, its symptoms, causes, diagnosis, and available treatments is essential for individuals at risk and for those already diagnosed with the disease.

Symptoms and Causes

Lung cancer can manifest a wide range of symptoms, depending on the type, location, and stage of the disease. However, many of the lung cancer symptoms may also be indicative of other respiratory conditions, making it crucial to seek medical attention promptly.

Common symptoms of lung cancer include:

• Persistent cough
• Shortness of breath (dyspnea)
• Coughing up blood (hemoptysis)
• Chest pain
• Wheezing (whistling sound while exhaling) or hoarseness
• Fatigue or weakness
• Unexplained weight loss
• Recurrent respiratory infections

In advanced stages, lung cancer may reach other body parts, leading to additional symptoms such as bone pain, headaches, or yellowing of the skin and eyes (jaundice).

Causes

One of the most common causes of lung cancer is exposure to carcinogens. Carcinogens can damage DNA and lead to the development of cancerous cells. The primary risk factor is smoking tobacco products, including cigarettes, cigars, and pipes. Other potential causes include:

• Secondhand smoke exposure
• Exposure to radon gas
• Occupational exposure to asbestos, diesel exhaust, or certain chemicals
• Air pollution
• Family history of lung cancer
• Radiation therapy to the chest area

Diagnosis and Tests

Lung cancer diagnosis involves a combination of imaging tests, laboratory tests, and tissue sampling procedures. Early and correct diagnosis is crucial for curating the best treatment plan and improving the chances of successful management.

The diagnostic process may include the following tests:

• Chest X-ray: This is often the first step in diagnosing lung cancer, as it can reveal lung abnormalities or masses.
• Computed Tomography (CT) Scan: A CT scan provides in-depth, cross-sectional images of the lungs and surrounding structures, allowing for better visualisation of tumours and their extent.
• Positron Emission Tomography (PET) Scan: This imaging technique uses a radioactive tracer to indicate areas of increased metabolic activity, indicating the presence of cancerous cells.
• Sputum Cytology: In this test, a lab technician investigates a sample of mucus coughed up from the lungs under a microscope for the presence of cancer cells.
• Bronchoscopy: During this procedure, a flexible tube having a camera is inserted into the airways through the mouth or nose, allowing the doctor to visualise and collect tissue samples from suspicious areas.
• Needle Biopsy: A thin needle is inserted via the chest wall. It is done to obtain a sample of lung tissue or fluid from the area of concern.
• Surgical Biopsy: In some cases, doctors may perform a more invasive procedure called a thoracotomy or video-assisted thoracoscopic surgery (VATS) to remove a larger tissue sample for analysis.

Management and Treatment

The treatment of lung cancer depends on various factors, including the type & stage of the cancer, the patient’s overall health, and personal preferences. A multidisciplinary team of expert doctors, including oncologists, surgeons, radiation therapists, and support staff, collaborates to develop a holistic treatment plan curated according to each patient’s unique situation.

The treatment modalities for lung cancer include:

• Surgery: Surgical removal of the tumour and surrounding affected tissue is often the primary treatment for early-stage lung cancer. The type of surgery depends on the location and extent of the tumour, ranging from removal of a small portion of the lung (called wedge resection) to pneumonectomy (removal of an entire lung).
• Radiation Therapy: Radiotherapy uses high-energy radiation beams to kill cancer cells or prevent their growth. It can be used as a primary treatment for inoperable lung cancers or in combination with other treatments, such as surgery or chemotherapy.
• Chemotherapy: Chemotherapy involves the use of highly potent drugs to destroy cancerous cells or prevent their further growth. It can be used as a primary treatment for advanced or metastatic lung cancer or in combination with radiation therapy or surgery.
• Targeted Therapy: This approach targets specific molecular pathways or genetic mutations that drive the growth & spread of cancerous cells. These types of therapies are considered more effective, with fewer side effects than traditional chemotherapy.
• Immunotherapy: This emerging treatment harnesses the body’s immune system to recognise and attack cancer cells. Immunotherapies (checkpoint inhibitors and therapeutic vaccines) have shown encouraging results in treating certain types of lung cancer.

Prevention

While lung cancer cannot be a hundred per cent prevented, several steps can reduce their risk, such as:

• Quit Smoking & Avoid Secondhand Smoke: Smoking is the leading cause of lung cancer. Quitting smoking can significantly reduce the risk. Additionally, avoiding exposure to secondhand smoke is crucial for both smokers and non-smokers, says “Dr. Akshay Singh.”
• Test for Radon: It is a naturally occurring radioactive gas. It can accumulate in homes and increase the risk of lung cancer. Testing for and mitigating high radon levels is recommended.
• Avoid Occupational Exposures: Individuals working in certain industries, such as mining, construction, or manufacturing, may be exposed to carcinogens like asbestos, diesel exhaust, or chemicals. Proper protective equipment and adherence to safety protocols are essential.
• Maintain a Healthy Lifestyle: Eating a diet rich in fruits & vegetables, exercising regularly, and maintaining an optimal body weight can help reduce the chance of developing lung cancer & other chronic diseases.
• Consider Lung Cancer Screening: For individuals at high risk (heavy smokers or those with a significant smoking history), regular lung cancer screening with low-dose CT scans may be recommended to detect the disease at an early stage.

Prognosis

The prognosis for lung cancer varies widely and depends on a myriad of factors, including the type & stage of the cancer, the overall health, and the effectiveness of the treatment. Early detection & prompt treatment are crucial for improving the chances of survival and achieving a favourable outcome.

Generally, the earlier the stage at which lung cancer is diagnosed, the better the treatment outcome. For example, the 5-year survival rate for patients with initial-stage Non-Small Cell Lung Cancer (NSCLC) can be as high as 60-80%, while the 5-year survival rate for advanced-stage NSCLC is typically less than 10%.

For Small Cell Lung Cancer, the prognosis is generally poorer, with a 5-year survival rate of around 6% for all stages combined. However, early-stage SCLC may have a better prognosis, with a 5-year survival rate of approximately 25-30%.

Living With Lung Cancer

Being diagnosed with cancer of the lungs can be a life-altering experience. It impacts a person both physically and emotionally. Coping with the challenges of the disease, treatment, and its impact on daily life can be overwhelming for patients and their loved ones. However, various strategies and resources are available to help individuals navigate this journey.

• Emotional Support: Taking emotional support from loved ones, support groups, or mental health experts can be invaluable in managing the stress, anxiety, and emotional challenges associated with lung cancer. Counselling, therapy, or joining a support group can provide a personalised space to share experiences and learn coping strategies.
• Lifestyle Modifications: Making lifestyle adjustments, such as adopting an optimal diet, engaging in regular physical activity (as tolerated), and practising stress management techniques like meditation or yoga, can help improve overall wellness and potentially enhance treatment outcomes.
• Pain Management: Lung cancer and its treatments can cause various types of pain, including chest pain, bone pain, or nerve pain. Working with the medical team to develop an effective pain management plan is crucial for maintaining quality of life.
• Palliative Care: It focuses on giving relief from the symptoms and stress of lung cancer, regardless of the stage or prognosis. This multidisciplinary approach aims to make life better for both patients and their families through physical, emotional, and spiritual support.
• Advance Care Planning: Having open and honest conversations about end-of-life preferences and advance care planning can help ensure patients’ wishes are respected, and their loved ones are prepared for difficult decisions.
• Clinical Trials: Clinical trials can give people access to cutting-edge treatments & contribute to the advancement of lung cancer research. Discussing clinical trial options with the medical team can be a valuable consideration.

FAQs

What type of disease is lung cancer?

Lung cancer is a malignant ( cancerous) growth that develops in the lungs. It starts when healthy cells in the lungs mutate and grow out of control. These abnormal cells form tumours that can invade nearby tissues and reach other body parts.

What is lung cancer caused by?

The principal cause of cancer in the lungs is smoking tobacco in any form. Smoking damages the lung cells, making them more likely to turn cancerous. Exposure to secondhand smoke, radon gas, and certain workplace chemicals can also increase your risk of developing lung cancer.