What is Lung Cancer?
The CDC defines lung cancer as, "cancer is a disease in which cells in the body grow out of control." This means the cells in the lungs stray from their growth pattern and death cycle. There are two main types of lung cancer; non-small cell and small cell. Both types of lung cancer have different approaches for treatment.
Non-Small Cell Lung Cancer
Non-small cell lung cancer (NSCLC) is the most common, accounting for about 80% - 85% of lung cancers. NSCLC consists of three subtypes, lung adenocarcinoma, squamous carcinoma, and large cell carcinoma.
Lung Adenocarcinoma
Of the 85% of non-small cell lung cancer, 40% of cases are lung adenocarcinoma. Lung adenocarcinoma begins in the glandular cells and is located more along the outer edge of the lungs. This type of cancer can be found more commonly in females and seen in people who don't smoke. It is also more common to occur in younger people than any other type of lung cancer.
This type of lung cancer spreads slower than the other types of lung cancers and is likely to be detected before it spreads to other parts of the body.
Researchers have been very successful in identifying the driver mutations in lung adenocarcinoma. Driver mutations are referred to the many different mutations that lead to lung cancer.
Researchers are constantly studying mutations that can lead to lung cancer. Identifying driver mutations has led to the discovery of cancer treatments and therapies targeted to treat and attack specific parts of cancer cells.
Squamous Cell Carcinoma
Squamous cell lung cancer is also called epidermoid carcinoma and is the second most common NSCLC. It is also the most common type of lung cancer diagnosed in seniors. Of the 85% of non-small cell lung cancer, 30% of cases are squamous lung cancer.
Squamous cells line the inside of the airways of the lungs. When a squamous cell lung tumor occurs, it usually occurs in the left or right bronchus (airway) or the central part of the lung. It can spread to multiple areas, including the brain, spine, adrenal glands, and liver.
One risk factor for people who are diagnosed with squamous cell lung cancer have a history of smoking.
Large Cell Carcinoma
Of the 85% of non-small cell lung cancer, 10% of cases are large cell lung cancer. The majority of large cell lung cancer is found in the periphery and is commonly diagnosed in men.
Large cell lung cancer can appear in any part of the lung and spreads quickly. This can make treatment difficult.
Small Cell Lung Cancer
Small cell lung cancer (SCLC) derives its name because of how the cells look under a microscope. Don't let the name fool you, the cells may be smaller than normal, but this type of lung cancer is very aggressive, growing and spreading rapidly. SCLC is also called small cell carcinoma or oat cell cancer and accounts for about 10% - 15% of all lung cancers.
SCLC usually begins in the bronchi. However, there are some occasions where it's found in the periphery of the lungs. It can quickly grow and spread to other parts of the body. About 70% of people with SCLC will have cancer that has already spread by the time they are diagnosed.
SCLC generally grows and spreads faster than NSCLC but usually responds well to treatment. Chemotherapy and radiation are effective treatments but, SCLC often reoccurs in those who develop it.
SCLC can be categorized into two types, small cell carcinoma and combined small cell carcinoma.
The World Health Organization defines combined small cell lung carcinoma as "small cell carcinoma combined with an additional component consisting of any non–small cell histologic type."
What Is The Difference Between SCLC and NSCLC?
Small-cell lung cancer grows rapidly
Small-cell lung cancer spreads quickly
Small-cell lung cancer responds well to treatment (chemotherapy and radiation therapy)
Lung Carcinoid Tumors
Lung carcinoid tumors are another type of lung cancer and are sometimes called lung carcinoids. They form in the neuroendocrine cells of the lungs. They are not a very common type accounting for about 1% - 2% of all lung cancer cases and tend to be present in more women than men. The two main types of lung carcinoid tumors are typical carcinoids and atypical carcinoids. About 25% of people with carcinoid tumors of the lung do not have symptoms at the time of discovery.
Did you know: There are about 2,000 to 4,500 newly diagnosed lung carcinoid tumors in the United States each year.
Typical Carcinoids
They grow at a slow pace and rarely spread beyond the lungs. About 9 out of 10 lung carcinoids are typical carcinoids. Typical carcinoids cases aren't directly linked to smoking.
On average 45-year olds are more commonly diagnosed and roughly 85% to 90% live another five years or more. 80%-90% of typical carcinoids develop in the small airway, while about 10% arise in the big airway. Around 10% appear around the edges of the lung.
Survival rates for a cancer patient with typical carcinoids after five years are 78% to 95%. The 10-year survival rate for a cancer patient is 77% to 90%. When a typical carcinoid is surgically removed, it is rare for it to come back.
Atypical Carcinoids
Atypical carcinoids are the opposite of typical carcinoids. They grow faster, may have greater chances of spreading to other organs, and may be related to smoking. They occur less frequently than typical carcinoids and have cells that resemble those of a fast-growing tumor.
The average age for this diagnosis is 55. For people with atypical carcinoids, 50% to 70% live another five years or more. Although typical carcinoids are usually diagnosed at the earliest stage of disease (stage 1), over half are found at more advanced stages.
Survival rates for a cancer patient with atypical carcinoids after five years are 40% to 60%. The 10-year survival rate for a cancer patient is 31% to 60%. It is more common for atypical carcinoids to return after treatment than typical carcinoids; this happens in around 26% of people with an atypical carcinoid.
It is more common for atypical carcinoids to return after treatment than typical carcinoids; this happens in around 26% of people with an atypical carcinoid.
Doctors sometimes classify lung carcinoid tumors based on where they first developed in the lungs:
Central carcinoids comprise the majority of lung carcinoid cases. These tumors develop in the bronchi, which are large airways near the middle of the lungs. Most central carcinoids are typical carcinoids.
Peripheral carcinoids develop in the bronchioles, which are smaller airways near the outer regions of the lungs. The majority of peripheral carcinoids are also typical carcinoids.
Rare Types of Non-small Cell Lung Cancer
Adenosquamous Carcinoma
Adenosquamous carcinoma of the lung is a type of hybrid tumor that combines adenocarcinoma and squamous cell lung cancer. It is a rare subtype of non-small cell lung cancer, making up 0.4-4% of all lung cancer cases.
Unfortunately, people with adenosquamous carcinomas tend to survive for shorter lengths of time than those with pure adenocarcinomas or squamous cell carcinomas of the lung. For a significant number of people with adenosquamous carcinomas, the cancer spreads (metastasizes) to the brain.
Large Cell Neuroendocrine Carcinoma
Large cell neuroendocrine carcinoma is an aggressive subtype of non-small cell lung cancer that represents about 3% of all lung cancers. It is a neuroendocrine tumor, meaning it develops from cells of the nervous and endocrine (hormonal) systems.
Survival rates for a cancer patient with large cell neuroendocrine carcinoma after five years or more after their diagnosis without cancer returning is 27.5%. 35.3% of cancer patients live for another five or more years after their diagnosis. Most relapses happen within the first two years.
Salivary Gland-Type Lung Carcinoma
Salivary gland-type lung carcinoma accounts for 0.1% to 0.2% of all lung cancers. They include adenoid cystic carcinomas and mucoepidermoid carcinomas of the lung. Salivary gland-type carcinomas were previously known as bronchial adenomas.
They are thought to come from the glands of the airways, and the tumors are usually in the airways. which is most often found in the central airways of the lungs.
Studies report that survival rates for people with salivary gland-type lung carcinomas that had their tumor surgically removed after three years are 82%. After five years the survival rate is 70% and 10-years is 63%.
Sarcomatoid Carcinoma and Mesothelioma Lung Cancer
Between 0.3% and 3% of all non-small lung carcinomas are sarcomatoid carcinomas. Most people diagnosed with this type of cancer are have a history of smoking or are current heavy smokers. There is some pondering about sarcomatoid carcinoma of the lung overlaps with mesothelioma.
Mesothelioma lung cancer starts in the covering of the lungs (pleura) and is caused by exposure to asbestos. Mesothelioma, a rare type of cancer that develops in thin tissue called mesothelium, which lines the lungs and abdomen.
Like mesothelioma, sarcomatoid carcinoma usually develops in the pleura and has a very slow onset and progression. Sarcomatoid carcinoma is very aggressive. Overall, 20% of people with sarcomatoid carcinoma lived for five years or more after their diagnosis.
Granular Cell Lung Tumors
Granular cell lung tumors are extremely rare, making up 0.2% of all lung tumors. It is even rarer they have malignant (cancerous) cells. These are usually small, firm, solitary nodules found either blocking or surrounding the airways and causing them to narrow.
Mediastinal Tumors
Mediastinal tumors are also rare and develop in the mediastinum. The mediastinum separates the lungs in the center of the chest. The trachea (or windpipe), esophagus, heart, connective tissues, and other organs are part of the mediastinum. In adults, most mediastinal tumors form in the front of the mediastinum.
Mediastinal tumors typically fall into one of the following categories:
Germ cell tumors
Malignant, or cancerous, lymphomas
Thymomas
Other extremely rare forms of lung cancer include sarcomatoid carcinoma of the lung and malignant granular cell lung tumors.