Our body is made up of a trillion of cells, and all of them contain DNA. These cells replicate and form an identical copy when they divide. This is a continuous process in which older cells die, and new ones develop to replace them. Mutations take place when there is an error in the replication of cells. They can potentially cause cancer in any part of the body. Cancer that begins in the lung is known as lung cancer.
In the United States, 228,820 new cases of lung cancer are expected the next year. Lung cancer percentage has reduced by about 3% in men and 1.5% in women annually from 2007-2016. The risk is 15% higher for black men than white men, but the disease is 14% more threatening for white women than black women. The death rate from lung cancer was reduced by 51% in men since 1990 and 26% in women since 2002.
In this article, you’ll go through the various types of lung cancer, their stages, diagnosis, and treatment methods. This article will also highlight the common symptoms and complications of lung cancer. After reading the article, you’ll be able to identify the type of lung cancer by its symptoms and understand your doctor when he recommends a treatment method.
Lung Cancer and Its Common Symptoms
Primary or secondary lung cancer may occur. Primary lung cancer occurs in the lungs and doesn’t spread to other parts. In contrast, secondary lung cancer occurs in any part of the body and spreads to the lungs through the blood or lymphatic system. Thus, the first type of lung cancer we need to discuss is metastasis or spread from other organs.
In any case, lung cancer can cause several symptoms. The main symptom is shortness of breath due to a blockage of airways or fluid accumulation around the lungs.
The second major symptom is coughing up blood. Sometimes, severe coughing with lung cancer can cause bleeding in the airways.
The third symptom is pain. Lung cancer in the inner part of the lung or outer part of the lung can cause body pain. Lastly, lung cancer can spread to other parts like the brain and bones. As a result, nausea, headache, vomiting, or wheezing can occur depending on which part of the body is affected.
Types Of Lung Cancer
Lung cancer is broadly categorized into two kinds which have more subtypes. The broad categories are known as “Small Cell Lung Cancer (SCLC) and Non-Small Cell Lung Cancer (NSCLC).” The percentage of NSCLC is 80-85% across- world. In contrast, SCLC is less common, and near -about 10-15% of lung cancer is SCLC.
- Sub-types of Non-Small Cell Lung Cancer (NSCLC): The sub-categories of NSCLC are “large cell carcinoma, squamous carcinoma, and adenocarcinoma.” These are categorized on the base of their lung cells from where they start.
- Adenocarcinoma: Adenocarcinoma starts in the cells of the lungs that synthesize mucus and other secretions. This type of cancer is more common in women than men and mostly occurs in younger people. It can affect current smokers, old smokers, or even non-smokers. It is usually diagnosed at the early stage before spreading and is mostly found in the outer parts of the lung. It makes up about 40% of lung cancer cases.
- Squamous carcinoma: Squamous carcinoma occurs in the cells of the airways of the lungs. This kind of lung cancer commonly occurs in the center of the lung. The most affected people by this cancer are smokers, either a current smoker or former smoker. It grows and spreads more quickly than other kinds of lung cancer, making it more difficult to treat. It makes up about 10% of lung cancer cases.
- Large-cell carcinoma: In this case, cancer is not squamous carcinoma or adenocarcinoma. This is a diagnosis of exclusion when the tumor cannot be classified into specific lung cancer types. Thus, it is a heterogeneous group of undifferentiated cancers.
- Small-Cell Lung Cancer (SCLC): SCLC is not commonly diagnosed at an early stage. It grows and spreads more speedily than NSCLC. SCLC is also called an “oat-cancer” due to its oat-like appearance under a microscope. It mostly occurs in the bronchi of the lungs and spreads toward other body organs, the pleural fluid, and lymphatic nodes.There are two main subtypes of SCLC. This categorization depends on the cells in which it occurs and how the cells look when observed under a microscope. The two types are “small-cell carcinoma and combined small cell carcinoma.” These types of lung cancer are more threatening and require treatment as soon as possible.
- Small-cell carcinoma: Small-cell carcinoma is a subtype of small-cell lung cancer that occurs within the lung. It occurs in the cells of the central airways and narrows down the bronchial airway. Common symptoms of small-cell carcinoma are weight loss, cough, and weakness. It is a type of secondary lung cancer that can spread to other body organs such as the bone, brain, and liver.
- Combined small-cell lung cancer: Combined small-cell lung cancer occurs with other forms of lung cancer such as squamous cell carcinoma. Its symptoms are similar to other kinds of lung cancer.
Stages Of Lung Cancer
There are different stages for both main branches of lung cancers according to how much cancer is spread. The chances of treatment increase when lung cancer is diagnosed at an early stage. Diagnosis can be achieved by specific tests such as imaging tests or sputum cytology.
- Stages of Non-Small Cell Lung Cancer: There are four stages for NSCLC. During the first phase, lung cancer is only found in the lung, and it is not very large. During the second phase, lung cancer is larger than 4 cm. Besides, it takes the lymph nodes but only inside of the lung. During the third phase, the tumor is larger, it can be spread locally in the chest, and lymph nodes outside of the lungs are taken. During the fourth and more threatening stage, cancer is very large, it has taken the surrounding areas, and it may have spread to other organs.
- Stages of Small-Cell Lung Cancer: We can summarize SCLC into two stages. The first stage is known as the “limited stage”. In the limited-stage, cancer can be diagnosed in the lung, nearby lymph node, or the chest. “Extensive stage” is after the limited stage of cancer. During the extensive stage, cancer has spread to the bone marrow, opposite lung, lymph nodes, pleural fluid, and surrounding tissues.
References:
Siddiqui, F., & Siddiqui, A. H. (2020). Cancer, lung. StatPearls [Internet].
Cersosimo, R. J. (2002). Lung cancer: a review. American journal of health-system pharmacy, 59(7), 611-642.
Rami-Porta, R., Crowley, J. J., & Goldstraw, P. (2009). Review the revised TNM staging system for lung cancer. Ann Thorac Cardiovasc Surg, 15(1), 5.
