Lung Cancer: Symptoms, Risk Factors, Diagnosis & Treatments

Lung cancer is among the most common cancers and a leading cause of cancer deaths globally. The risk of this cancer is higher in people who smoke heavily, although it is also found in people who have never smoked. Over 238,000 new U.S. cases were expected in 2023, according to the American Cancer Society. Awareness of symptoms, risk factors, and treatment options is vital, as it can simply happen from everyday things. Early detection plays a key role in improving survival rates.

What is Lung Cancer?

Lung cancer refers to the uncontrolled growth of abnormal cells in the lungs, leading to the formation of tumors. It is primarily classified into two main types: non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC).

• Non-Small Cell Lung Cancer (NSCLC): NSCLC is the most common type, accounting for 80-85% of lung cancer cases. It typically develops in the outer parts of the lung and grows slower than SCLC. Common subtypes include adenocarcinoma, which begins in peripheral lung tissue, and squamous cell carcinoma, which starts in the airways.

• Small Cell Lung Cancer (SCLC): SCLC makes up about 10-15% of lung cancer cases and is characterized by rapid growth and early metastasis. It is strongly associated with smoking and typically originates in the central airways.

• Lung Carcinoid Tumors: These rare neuroendocrine tumors develop in the lungs and are usually slow-growing. They can occur in patients with no history of smoking and may present with symptoms such as coughing and recurrent infections. Surgical removal is the primary treatment for localized tumors, with a generally favorable prognosis.

According to the American Cancer Society, lung cancer is the second most common cancer in both men and women, with an estimated lifetime risk of about 1 in 16 for men and 1 in 17 for women. 

Main Risk Factors for Lung Cancer

Understanding the primary risk factors for lung cancer helps with prevention and early detection. These factors include:

• Age: Risk increases with age, especially over 65, due to cumulative exposure to carcinogens.

• Family History: A genetic predisposition raises risk, particularly among first-degree relatives, indicating potential inherited mutations.

• Smoking: The leading cause, responsible for 85% of cases. Smokers are 15-30 times more likely to develop lung cancer due to carcinogens in tobacco causing genetic mutations.

• Secondhand Smoke: Non-smokers exposed to secondhand smoke face a 20-30% higher risk of lung cancer.

• Environmental Pollution: Long-term exposure to pollutants like radon, diesel exhaust, and industrial emissions raises lung cancer risk.

• Occupational Hazards: Jobs involving carcinogens like asbestos and arsenic significantly increase lung cancer risk.

Early Symptoms of Lung Cancer

Identifying early symptoms of lung cancer is crucial for timely intervention. Common early symptoms include:

• Persistent Cough: A cough that lasts longer than usual, particularly if it worsens over time.

• Coughing Up Blood: Hemoptysis, or coughing up blood, can be a sign of lung cancer and requires immediate medical evaluation.

• Chest Pain: Persistent or worsening chest pain, especially during breathing, coughing, or laughing, may indicate lung issues.

• Shortness of Breath: Difficulty breathing or wheezing, especially during routine activities, can signal lung problems.

• Unexplained Weight Loss: Significant weight loss without an apparent cause can be a symptom of various cancers, including lung cancer.

• Fatigue: Unusual or extreme fatigue that does not improve with rest is a common complaint among lung cancer patients.

• Frequent Respiratory Infections: Recurring bronchitis or pneumonia may indicate underlying lung pathology and should be evaluated by a doctor.

How Lung Cancer is Diagnosed

Diagnosis of lung cancer typically involves a combination of imaging studies and tissue sampling to confirm the presence of cancer cells. Common diagnostic methods include:

• Chest X-rays: Often the first evaluation step for respiratory symptoms, these can reveal lung structure abnormalities.

• CT Scans: Providing detailed cross-sectional images, CT scans help identify tumors and assess their size and location.

• Needle Biopsy: This technique uses a fine needle to extract a tissue sample from the tumor for pathological examination, often guided by imaging for accuracy.

• Bronchoscopy: In this procedure, a thin, flexible tube with a camera is inserted into the airways, allowing visual inspection of the lungs and collection of tissue samples from suspicious areas.

• PET Scans: Utilizing radioactive tracers, PET scans highlight cancerous areas, determining disease extent and whether it has spread to other organs.

• Molecular Testing: This analysis evaluates cancer cells for specific genetic mutations, such as EGFR or ALK, guiding targeted therapies and personalizing treatment plans.

Lung Cancer Stages and Grading Score

The staging of lung cancer describes the extent of disease progression, which helps guide treatment decisions:

• Stage 0: Carcinoma in situ, where abnormal cells are present, but no invasive cancer is detected.

• Stage I: Tumor is small (up to 3 cm) and localized to the lung, with no lymph node involvement.

• Stage II: Tumor is larger or more invasive and may involve nearby lymph nodes.

• Stage III: Locally advanced cancer that has spread to nearby tissues and lymph nodes but not to distant organs.

• Stage IV: Advanced cancer with metastasis to distant organs like the brain, liver, or bones, often requiring more intensive treatment.

Grading

Grading refers to the assessment of how abnormal the cancer cells look under a microscope. Grading helps determine the tumor's aggressiveness:

• Low-Grade (Well-Differentiated): Cancer cells resemble normal cells and grow slowly, associated with a better prognosis.

• Intermediate-Grade (Moderately Differentiated): Cancer cells show moderate abnormality and growth rate.

• High-Grade (Poorly Differentiated): Highly abnormal cancer cells with rapid growth and spread, often requiring aggressive treatment.

Treatment Options for Lung Cancer

Treatment for lung cancer varies based on type, stage, and individual patient factors. Common options include:

• Surgery: Used for early-stage NSCLC. Procedures include lobectomy (removal of a lung lobe), pneumonectomy (entire lung removal), or wedge resection (removal of a small lung section).

• Chemotherapy: Systemic treatment with cytotoxic drugs, used in SCLC and advanced NSCLC to kill rapidly dividing cancer cells.

• Radiation Therapy: High-energy rays target cancer cells. It can be used as a primary treatment or palliative care and delivered externally or through internal radiation (brachytherapy).

• Targeted Therapy: These drugs attack specific genetic mutations in cancer cells. Common options in NSCLC include Erlotinib, Gefitinib, Afatinib, and Bevacizumab.

• Immunotherapy: Drugs like Pembrolizumab boost the immune system's response to cancer, often used for advanced NSCLC.

Medications for Lung Cancer

Various medications are commonly used in lung cancer treatment, each with different mechanisms of action. These are only some common examples. However, you might be prescribed something different if you have certain conditions.

• Docetaxel: A chemotherapy drug that stabilizes microtubules, disrupting cell division. It is effective across various lung cancer stages.

• Erlotinib: A targeted therapy that blocks the epidermal growth factor receptor (EGFR), preventing cancer cell growth in patients with specific genetic mutations.

• Gefitinib: Similar to Erlotinib, it targets EGFR mutations in NSCLC, enabling a personalized treatment approach based on genetic profiling.

• Afatinib: An irreversible EGFR inhibitor used for patients with specific mutations, offering a different mechanism compared to Erlotinib and Gefitinib. However, you can see the price difference between Afatinib cost and Geftinib cost.

• Gemcitabine: A nucleoside analog that interferes with DNA synthesis, commonly used with other agents for NSCLC treatment.

• Pembrolizumab: An immune checkpoint inhibitor that enhances the immune system's ability to recognize and attack cancer cells, especially in advanced lung cancer stages.

• Paclitaxel: A chemotherapy agent that inhibits cell division, frequently used in combination with other chemotherapy drugs to treat lung cancer.

• Bevacizumab: A monoclonal antibody that inhibits angiogenesis, blocking tumor blood supply development. Often combined with chemotherapy for advanced NSCLC.

Risk Reduction for Lung Cancer

Reducing lung cancer risk involves lifestyle and environmental changes:

• Quit Smoking: Quitting smoking is the most effective way to lower lung cancer risk. Avoid firsthand and secondhand smoke.

• Avoid Carcinogens: Limit exposure to asbestos, radon, and industrial chemicals. Test homes and workplaces for radon.

• Healthy Diet and Exercise: Eat fruits, vegetables, and exercise regularly to strengthen immunity and reduce cancer risk.

• Routine Screening: High-risk individuals, like long-term smokers, should get low-dose CT scans for early detection.

These actions reduce lung cancer risk and improve overall health.

Conclusion

Lung cancer is a leading cause of cancer mortality, but there is hope. Awareness of symptoms and risks leads to early intervention. New treatments, such as targeted therapies and immunotherapy, are improving outcomes. Prioritize early detection and collaborate with your doctor for a better quality of life. Schedule screenings and address symptoms early. Taking action can save your life.