What is lung cancer?
Like other cancers, lung cancer develops when normal processes of cell division and growth are disrupted, giving way to abnormal, uncontrollable growth. The cells grow into a mass, or tumor. Any abnormal growth in the body that directly invades surrounding tissues and organs, spreads to other parts of the body, or has the potential to grow back after being removed is called malignant, or cancerous.
Lung cancer symptoms may not be present when the disease is at an early stage, and some have no symptoms at all. For others, lung cancer symptoms can include cough, shortness of breath, chest pain and other respiratory symptoms.
Who gets lung cancer?
Lung cancer can take several years to develop. Cigarette smoking is the most common risk factor for developing lung cancer. Many people exposed to cigarette smoke or some of its components will end up with permanent abnormal changes in their lungs. These changes can cause a cancerous tumor to develop within the lung.
- It is estimated that 10 - 20% percent of all cases of lung cancer worldwide are diagnosed in people who have never smoked. The underlying cause in these cases is not well understood.
- Two out of three people diagnosed with lung cancer are over age 65
- The most common age at diagnosis is 70 years.
How common is lung cancer?
Lung cancer is the most common malignancy worldwide, with more than 1 million cases diagnosed yearly, making it the leading cause of cancer death in both men and women. Of those people born today, one in 14 men and women will be diagnosed with cancer of the lungs and bronchus (large air tubes leading from the windpipe to the lungs) during their lifetime.
How is lung cancer diagnosed?
Usually, lung cancer is a concern when an abnormal finding is seen on a chest imaging study or when the disease is advanced enough to cause symptoms, such as coughing, shortness of breath, chest pain, fatigue and/or weight loss.
Diagnosis requires a biopsy, or the removal of cells or tissues from the suspicious mass. Surgery may be needed to confirm a diagnosis.
Today, the availability of innovative techniques is revolutionizing the way lung cancers are diagnosed. They are facilitating an early detection process, meaning lung cancer can be identified at the earliest and most treatable stages.
What are the stages of lung cancer?
Staging defines the extent of cancer's growth and spread, providing a clear picture of how advanced the disease is, for example its size, location and whether it has spread toother parts. This information or staging is essential for tailoring treatment decisions and determine expected outcomes for each individual. Doctors use specific terms to describe the stages of cancer, but a straightforward way of describing staging might be as follows:
- Localized: the cancer is confined to the lung.
- Regional: the cancer has spread to lymph nodes (or glands) within the chest. Lymph nodes act as a filtering system outside the lung, collecting cancer cells that are beginning to migrate out of the lung.
- Distant: the cancer has spread (or metastasized) to other parts of the body.
What are the types of lung cancer?
About 90% of lung cancers start in the lining of the bronchi (air passageways branching off the trachea, or breathing tube). Lung cancer also can form in glands below the lining of the bronchi, frequently in the outer edges of the lungs. These lung cancers are one of two major types, small cell or non-small cell lung cancer, each of which grows and spreads different ways:
Non-small cell lung cancer (NSCLC)
Non-small cell lung cancer is the most common form of lung cancer, and usually grows and spreads more slowly than small cell lung cancer. There are three main types of non-small cell lung cancer, named after the cells within which the cancer develops:
- Adenocarcinoma often starts growing near the outside surface of the lung and may vary in both size and growth rate. This is the most common type of lung cancer in both smokers and those who have never smoked.
- Squamous cell carcinoma usually starts in one of the larger breathing tubes near the center of the chest.
- Large cell carcinoma often starts near the surface of the lung, grows rapidly and is usually quite extensive when diagnosed.
Small cell lung cancer
Small cell lung cancer is less common than non-small cell lung cancer, accounting for about 15 percent of all lung cancers. This type of lung cancer however grows fairly rapidly and has often spread to other parts of the body by the time it is diagnosed.
How is lung cancer treated?
All relevant information about the patient, including his or her health status, the kind of tumor and how far it has spread are brought together to design a personalized and patient centered treatment plan for that individual's cancer.
Treating lung cancer presents significant challenges, and the stage at diagnosis plays a critical role in survival. When lung cancer is caught early and is still in one place (localized), it's often curable. However, many people are diagnosed later, when the cancer has spread beyond the chest or to nearby lymph nodes (regional or distant). This highlights the importance of early detection and personalized treatment plans tailored to each patient's needs.
Treatment for lung cancer may include:
- Surgery: If lung cancer is in the earliest stages, surgically removing the tumor can cure the disease. The type of surgery offered will depend on many factors including the tumor size, location and the patient’s overall health. Many minimally invasive surgeries are now available which are suitable for some patients. Advanced, minimally invasive options include:
- Robotic-assisted thoracoscopic surgery: A highly precise camera and robotic surgical system allow enhanced visual perception and magnification, and more surgical precision and stability.
- Video-assisted thoracic surgery (VATS): A tiny camera is inserted through an incision, allowing surgeons to see inside the chest and perform surgery with specialized instruments.
- Chemotherapy: Medications that are designed to kill rapidly growing abnormal cells, such as cancer cells. Chemotherapy is injected directly into the veins or given orally in pill form.
- Targeted therapies: Targeted therapies target certain molecules or pathways involved in the growth and survival of cancer cells. Targeted therapies are effective at treating different stages of lung cancer.
- Immunotherapy: A treatment that helps your immune system identify and attack cancer cells more effectively. Examples include immune checkpoint inhibitors which block the proteins which suppress an immune response and allow immune cells to find and destroy cancer cells.
- Radiation therapy: Focused beams of energy are used to kill cancer cells and minimize damage to surrounding healthy tissue. Treatment is usually delivered externally but can also be delivered internally. Advanced options such as radiosurgery may be suitable for some patients, which delivers very high doses of radiation which is precisely focused at the tumor.
- Microwave ablation (MWA): High frequency electromagnetic waves generate heat and kill cancerous cells.
- Stereotactic body radiation therapy (SBRT): High-dose radiation is delivered precisely to the tumor, without damaging surrounding healthy tissues. Advanced imaging precisely maps the tumor's location and highly focused radiation beams are delivered from multiple angles