Lung cancer is a disease where malignant (cancer) cells form in the tissues of the lungs, most commonly in the cells that line the air passages. This condition develops when these cells begin to grow and multiply without control, often due to exposure to toxins such as tobacco smoke, radiation, and asbestos.
Traditional diagnosis categorises the disease by the type of cell where it begins:
Representing about 85% of cases, NSCLC arises from the epithelial cells that line the surface of the organs. Subtypes include adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.
Accounting for about 15% of lung cancers, SCLC is almost always caused by smoking tobacco. It typically starts in the central chest, is highly aggressive, and spreads quickly. For this reason, surgery is used less often for SCLC than for NSCLC.
Doctors can also diagnose the disease on a molecular level by looking for mutations in the DNA and/or proteins of cancer cells. These subtypes (such as mutations to the EGFR, ALK, KRAS, and ROS1 genes) are crucial as they predict how the cancer will respond to specific treatments, allowing SSCHRC doctors to design highly personalised care plans.
A risk factor is anything that increases the likelihood of developing a disease. The primary risk factors for lung cancer include:
Lung cancer symptoms can vary widely, and some people may not experience any signs at all, especially in the early stages. Often, symptoms are easily mistaken for common respiratory infections like bronchitis or pneumonia, which can unfortunately delay an accurate diagnosis. It is important to discuss any persistent or unusual symptoms with your doctor.
If lung cancer spreads (metastasises) to other parts of the body, it may cause additional symptoms, including:
These symptoms do not automatically mean you have lung cancer, as many other conditions share similar signs (such as chronic bronchitis, pneumonia, asthma, COPD, and tuberculosis). However, you should see a doctor if you experience any persistent cough, notice blood in your mucus, have chest pain or trouble breathing, feel constantly tired or weak without reason, lose weight without trying, or get frequent lung infections. Early detection offers the best chance of a successful outcome.
Because early-stage lung cancer often has no symptoms or symptoms that mimic common illnesses, many cases are diagnosed at an advanced stage. Patients at high risk for lung cancer, particularly those with a history of smoking, should discuss regular screenings with their doctor to catch the disease early.
If you present with symptoms that could indicate lung cancer, your doctor will begin by taking a detailed history, asking about your medical, smoking, and family history, and any exposure to chemicals or substances. This is typically followed by an imaging exam, such as a chest X-ray. If the images show an area of concern, further scans like a CT scan or PET scan may be ordered to gather additional details.
If imaging suggests cancer, a tissue or fluid sample is required for a definitive diagnosis. This procedure is called a biopsy. Doctors may use several methods to perform a lung tumour biopsy:
After diagnosis, the cancer is staged to determine the size of the primary tumour and how far it has spread. This information is critical for the care team to understand the disease and plan the appropriate treatment.
Used for most cancers, including non-small cell lung cancer, this system describes the cancer based on three factors:
The TNM stages are often simplified into four main stages, with larger numbers indicating more advanced cancer.
Due to its tendency to spread early, SCLC is usually classified into two stages:
At SSCHRC, a multidisciplinary team of lung specialists customises treatment to deliver the most advanced, effective, and least invasive therapies available, with a focus on preserving lung function and quality of life. Treatment plans are based on factors including the stage and type of lung cancer, other existing lung problems (e.g., emphysema), and overall health.
Surgery is often a viable option for those with early-stage non-small cell lung cancer. In some cases, chemotherapy or radiation may be given before surgery (neoadjuvant therapy) to shrink the tumour. The most common types of surgery, in order of tissue removed, include:
Removal of the tumour and a small, wedge-shaped piece of the lung around it.
Removal of an anatomical segment of the lobe where the cancer is located. Both this and wedge resection are often used for small, early-stage tumours or for patients with limited lung capacity.
Removal of the entire lung lobe containing the cancer. This is considered the "standard of care" for most surgical patients.
A more complex lobectomy for centrally located tumours, involving removal of the lobe and part of the connecting bronchus, which is then reconnected. It is preferred over pneumonectomy to preserve lung tissue.
Removal of an entire lung. This is occasionally necessary due to tumour location but is generally well tolerated by people with otherwise healthy lungs.
During most procedures, lymph nodes are also removed for examination to determine if the cancer has spread outside the lungs, which helps guide any necessary further treatment (adjuvant therapy), such as chemotherapy, radiation, or targeted therapy.
Surgical approaches include Open Surgery (traditional incision) and Minimally Invasive Surgery which uses smaller incisions, resulting in shorter recovery times and less pain. Minimally invasive methods include Video-Assisted Thoracic Surgery (VATS) and Robotic-Assisted Surgery.
Radiation therapy uses focused, high-energy photon or proton beams to destroy cancer cells. SSCHRC has radiation oncologists dedicated exclusively to lung cancer care. Treatments include:
Systemic therapy refers to treatments using substances that travel through the bloodstream to affect cells throughout the body. Significant advancements have been made in this area, particularly in targeted and immune therapies.
These therapies stop or slow cancer growth by interfering with specific molecules (like proteins) that cancer cells use to survive and multiply. They are currently available for many subtypes of adenocarcinoma.
These treatments harness the body's own immune system to fight the cancer. The standard of care for non-small cell lung cancer often includes checkpoint inhibitor immunotherapies, which remove the immune system's natural "brakes," allowing it to attack the cancer cells.
Uses drugs to directly kill cancer cells by halting their growth. It is often combined with immunotherapy, which makes both treatments more effective.
These drugs disrupt the process of angiogenesis (creating new blood vessels) that tumours use to increase their blood supply and grow rapidly. They bind to molecules like Vascular Endothelial Growth Factor (VEGF), prohibiting the activation of this growth process.