May 22, 2024

Non-Small Cell Lung Cancer: Understanding the Most Common Type of Lung Cancer

What is Non-Small Cell Lung Cancer?
NSCLC occurs when abnormal cells grow in one or both lungs in an uncontrolled way and form tumors. The two major subtypes of NSCLC are adenocarcinoma and squamous cell carcinoma.

Adenocarcinoma
Adenocarcinoma begins in mucus-producing cells found in the outer parts of the lung. It is the most common type of NSCLC, accounting for about 40% of all lung cancer cases. Adenocarcinoma occurs more often in women than men and is often linked with smoking, though it can develop in non-smokers as well. The symptoms of adenocarcinoma include a cough that doesn’t go away, shortness of breath, chest pain, and coughing up blood. It may sometimes spread to other organs in the body before being detected. Treatment options include surgery, chemotherapy, radiation therapy, targeted therapy, or immunotherapy depending on how much the cancer has progressed.

Squamous Cell Carcinoma
Squamous cell carcinoma starts in squamous cells that line the inside of the airways in the lungs. It makes up about 30% of all Non-Small Cell Lung Cancer cases and is more common in heavy smokers, though not all cases are linked to smoking. Symptoms include a cough that doesn’t go away, shortness of breath, chest pain, hoarseness, and coughing up blood. It typically originates near the center of the chest and may spread to nearby lymph nodes or distant organs. Treatment options are similar to adenocarcinoma and involve surgery, chemotherapy, radiation therapy, targeted therapy or immunotherapy based on the extent of the cancer.

Large Cell Carcinoma
Large cell carcinoma is a less common but more aggressive type of NSCLC accounting for about 10-15% of lung cancer diagnoses. It gets its name because the cancer cells appear large and abnormal when viewed under a microscope. The cancer cells do not normally resemble squamous cells or glandular (adenocarcinoma) cells. Large cell carcinoma exhibits a poor prognosis and survival rate compared to the other subtypes because it typically spreads before detection. Symptoms are similar to other NSCLC types. Treatment options aim to stop or slow progression using a combination of surgery, radiation therapy, chemotherapy and immunotherapy based on how extensive the cancer has become.

Staging Non-Small Cell Lung Cancer
Staging is an important part of evaluating how far NSCLC has progressed. The stage provides useful information on prognosis and helps determine the appropriate treatment approach. The TNM (tumor-node-metastasis) system is commonly used to stage NSCLC into four main categories:

– Stage I – The tumor is small in size (3cm or less) and has not spread to lymph nodes or other organs.

– Stage II – The tumor is medium sized (between 3cm and 7cm) and may have spread to nearby lymph nodes on the same side of the chest.

– Stage III – The tumor is large (over 7cm) and has spread to lymph nodes near the lungs or mediastinum. It may have progressed even further.

– Stage IV – The cancer has metastasized and spread to other organs such as the brain, bones, liver or distant lymph nodes. At this point, it is considered advanced or metastatic lung cancer.

Prognosis and Treatment Based on Stage

Stage I NSCLC has a much better 5-year survival rate of 50-70% if completely removed through surgery. For early stage tumors, options include standard lobectomy (removal of a lung lobe), segmentectomy (removal of a section of the lung), or wedge resection. Chemotherapy or radiation may be given after surgery to further reduce the risk of recurrence.

The 5-year survival rate for Stage II disease which has spread to nearby lymph nodes is lower at 40-50% with multimodality treatment involving surgery followed by chemotherapy and/or radiation therapy. More advanced Stage III NSCLC with lymph node involvement has a 5-year survival of 20-40% even with aggressive combined treatment approaches involving chemotherapy, radiation and sometimes surgery if the tumor can be fully removed.

Stage IV metastatic NSCLC unfortunately has a much lower 5-year survival rate of only 5% due to the cancer having already spread to distant areas. While not considered curable at this point, treatment is aimed at prolonging life and controlling symptoms using a combination of palliative chemotherapy, targeted therapies, immunotherapy or radiation therapy directed at any symptomatic areas. Ongoing clinical trials continue evaluating new treatment strategies that may improve outcomes.

Prognostic Factors and Recurrence Risk

Some other factors like histology (cell type), tumor size, lymph node involvement, and distant metastasis affect prognosis for NSCLC beyond just the clinical stage. Other lab tests also provide useful prognostic information like biomarker testing. Recurrence rates depend on the initial stage but recurrence monitoring with regular medical exams, imaging studies, and blood tests are important even after initial treatment to detect new growths early on. Lifestyle changes like quitting smoking help prevent further lung damage and second cancers. Ongoing medical management aims to maximize recurrence prevention and help maintain the best quality of life possible.

In summary, non-small cell lung cancer represents the most frequent type of lung cancer. Understanding the different subtypes based on cell type, staging factors like tumor size and lymph node involvement, as well as prognostic indicators are key to guiding appropriate treatment and counseling a patient about expected outcomes.

Note:
1. Source: Coherent Market Insights, Public sources, Desk research
2. We have leveraged AI tools to mine information and compile it