Overview and Terms to Know

By Lynne Eldridge, MD 

Updated on July 01, 2022

 Medically reviewed by Doru Paul, MD

The are more than 200 different types of cancer, each of which is grouped under a larger cancer category like carcinomas, myelomas, leukemias, and so forth. Because of this, simply learning that you or someone you know has cancer doesn't tell you a whole lot. Cancer is not a single disease, and different types of cancers have different origins, treatments, and prognoses.¹

Some cancers are grouped based on the cell, tissue, or body region where they start. Others types of cancer are described by their genetic profile, tumor grade, or cancer stage. Learn all about them here.

 The History of Cancer: Discovery and Treatment

Primary vs. Metastatic

Primary cancer refers to the original tumor in the body. In some cases, cancer may start and be treated effectively enough to stay in the area in which it began.

That definition is pretty straightforward. Confusion over the term tends to lie in its use for cancer that has spread to another part of the body.

When a cancer travels (metastasizes) from its original site, it is named for the type of cancer cell or organ in which it began—not for the region of the body it has spread to. For example, if breast cancer begins in the breast and later spreads to the lung, it would not be called lung cancer. Instead, it would be referred to as primary breast cancer metastatic to the lungs.

A diagnosis of "invasive" cancer does not mean that your cancer has spread. Even a stage 1 cancer is referred to in this way, based on the appearance of the tumor under a microscope.

You may also hear the term secondary cancer. This is a second primary cancer unrelated to the original tumor that is found in another part of the body. In other words, the additional cancer just so happens to have occurred at the same time as the first cancer, but it did not happen because of spreading of cancer cells.

Healthcare providers are unable to determine where a cancer began in about 3% to 5% of cases, and only find evidence of cancer where it has spread.² This is referred to as an unknown primary, or cancer of unknown origin, with metastasis to the location where the cancer is discovered.

 Primary vs. Secondary Cancers

By Cell or Tissue Type

Verywell / Laura Porter

The name for many cancers derives from the type of cells in which the cancer begins. For example, you may have been told you have kidney cancer, but kidney cancers can differ significantly based on the type of kidney cell in which a tumor starts.

There are six major types of cancer based on cell type:³

NIH National Cancer Institute. Cancer Classification.

• Carcinomas

• Sarcomas

• Myelomas

• Leukemias

• Lymphomas

• Mixed types (including blastomas)

Carcinomas

Carcinomas are the most common cell type of cancer, accounting for 80% to 90% of cancers. These cancers arise in epithelial cells, which include the cells of the skin and those that line body cavities and cover organs.³

Carcinomas may be further broken down into:

• Adenocarcinomas: Adenocarcinomas begin in glandular cells that manufacture fluids, such as breast milk.

• Squamous cell carcinomas: Examples of squamous cells include those in the top layer of the skin, the upper portion of the esophagus and airways, and the lower portion of the cervix and vagina.

• Basal cell carcinomas: Basal cells are only present in the skin and are the deepest layer of skin cells.

• Transitional cell carcinomas: Transitional cells are epithelial cells that are "stretchy" and are present in the bladder and parts of the kidney.

In addition to these more specific cell types, carcinomas may be named based on their location. For example, breast carcinomas that arise in the milk ducts would be referred to as ductal carcinomas, whereas those that arise in the lobules are considered lobular carcinomas.

Carcinomas are the only cancer cell type that have a noninvasive phase, and therefore are the only cancers for which screening is routinely done.

Cancers that are still "contained" and have not spread through the basement membrane are referred to as carcinoma in situ (CIN). Cancer detected at this early, pre-invasive stage has an excellent prognosis.⁴

Sarcomas

Sarcomas are cancers of the bone and soft tissues of the body that are made up of cells called mesenchymal cells.⁵ This type of cancer affects bone, muscles (both skeletal and smooth muscle), tendons, ligaments, cartilage, blood vessels, nerves, synovial tissues (joint tissues), and fatty tissues.

Examples of sarcomas include:

• Osteosarcoma (bone cancers)

• Chondrosarcoma (cartilage cancers)

• Liposarcoma (fatty tissue cancers)

• Rhabdomyosarcoma (skeletal muscle cancers)

• Leiomyosarcoma (smooth muscle cancers)

• Angiosarcoma (blood vessel cancers)

• Mesothelioma (cancers of the mesothelium, the tissues that line the chest and abdominal cavities)

• Fibrosarcoma (cancers of fibrous tissues)

• Glioma and astrocytoma (cells of the connective tissue in the brain)

What's In a Name?

Generally speaking, cancerous tumors usually include the name of the particular cell type in which they began followed by "sarcoma." For example, a benign bone tumor might be called an osteoma, but a malignant tumor, an osteosarcoma.

Myelomas

Myeloma, also called multiple myeloma, is a cancer of cells in the immune system known as plasma cells. Plasma cells are the cells that manufacture antibodies.

Leukemias

Leukemias are cancers of the blood cells, and they originate in the bone marrow. Among blood-related cancers, leukemias are considered "liquid cancers" in contrast to myelomas and lymphomas.³ Since these cancers involve cells that circulate in the bloodstream, they are often treated like solid cancers that have spread. Examples include:

• Lymphocytic leukemias: These are cancers of white blood cells known as lymphocytes.

• Myelocytic leukemias: These are cancers of mature or immature cells known as myelocytes, such as neutrophils.

Both lymphocytic and myelocytic leukemias have forms that progress quickly (acute) and forms that take longer to develop (chronic).

Lymphomas

Lymphomas are a type of cancer that arises from cells of the immune system. These cancers may arise in lymph nodes or from extranodal sites such as the spleen, stomach, or testicles. These are broken down into:

• Hodgkin lymphoma

• Non-Hodgkin lymphoma

Blood-Related vs. Solid Cancer Types

Cancers may also be referred to as "solid" or blood-related cancers. Blood-related cancers include leukemias, lymphomas, and myelomas, while solid cancers include all others.

Mixed Types

It's not uncommon for a cancer to have characteristics of more than one type of tissue. Cancer cells differ from normal cells in many ways, one of which is referred to as differentiation.

Some cancers can look very much like the normal cells in which they originate. They are called well-differentiated tumors. Others may bear little resemblance to normal cells. You may see them described as undifferentiated on a pathology report.

In addition to this, most tumors are heterogeneous. This means that the cells in one part of a tumor may look very different from cells in another part of a tumor.⁶

For example, a lung cancer may have some cells that look like adenocarcinoma and others that appear to be squamous cell carcinoma. On a pathology report, this is called adenosquamous features.

Blastomas are a type that is sometimes separated out from the rest. These are cancers that occur in embryonic cells—cells that have not yet chosen a path to become epithelial cells or mesenchymal cells.

By Body Part/System

Types of cancer are also often described by the organs or organ systems in which they begin.

Central Nervous System Cancers

Central nervous system cancers include those that originate in tissues of either the brain or the spinal cord. Cancers that spread to the brain are not considered brain cancers, but rather brain metastases, and are far more common than primary brain cancers.⁷

Cancers that commonly spread to the brain include:

• Lung cancer

• Breast cancer

• Melanoma

Unlike tumors in other regions of the body, brain cancers do not often spread outside of the brain. Overall, however, the incidence of brain cancer has been increasing in recent years. Improving overall cancer survival rates means more metastatic cases (the longer someone lives with cancer, the greater the chances of it spreading).

 Gliomas and Brain Cancer

Head and Neck Cancers

Head and neck cancers can affect any region of the head and neck, from the tongue to the vocal cords. In the past, these cancers were most commonly seen in people who were both heavy drinkers and smokers.⁸

In recent years, however, human papillomavirus (HPV) has become an important cause of these cancers, with close to 10,000 people developing HPV-related head and neck cancers each year in the United States alone.

Two such cancers are:

• Oral cancer: Roughly 60-70% of all head and neck cancers are oral cancers.⁹ These cancers may involve the mouth, tongue, tonsils, throat (pharynx), and the nasal passageways.

• Laryngeal cancer (cancer of the vocal cords)

Breast Cancers

Many people are aware that breast cancer is an all-too-common cancer in women, but it's important to point out that men get breast cancer also. Approximately 1 in 100 breast cancers occur in men.¹⁰ The most common type of breast cancer is ductal carcinoma.

Since most breast cancers are carcinomas, they may sometimes be detected before they have become invasive. This is considered carcinoma in situ, or stage 0 breast cancer.

Breast cancer stages 1 through 4 are invasive stages of the disease. You may hear these more specific names:

• Ductal carcinoma in situ of the breast (DCIS) and lobular carcinoma in situ (LCIS): Carcinoma in situ is the earliest stage at which breast cancer can be detected and is considered stage 0. These cancers have not yet penetrated through the basement membrane and are considered non-invasive. They are most often detected when a biopsy is done for an abnormality on a screening mammogram.¹¹

• Invasive (infiltrating) breast cancer (both ductal and lobular): Once a breast cancer penetrates through the basement membrane, it is considered invasive.

• Inflammatory breast cancer: Inflammatory breast cancer, in contrast to other breast cancers, does not usually present as a lump. Rather, the early stages of the disease look like a redness and rash on the breast.

• Male breast cancer: When breast cancer occurs in men, it is more likely that there is a genetic component. A family history of breast cancer should prompt a discussion with your healthcare provider.

Respiratory Cancers

Cancers of the lung and bronchial tubes are the leading cause of cancer deaths in both men and women in the United States.¹² While smoking is a risk factor for these diseases, lung cancer occurs in never-smokers as well. In fact, lung cancer in these individuals is the sixth-leading cause of cancer deaths in the United States.

Lung cancer rates are decreasing overall, likely related to a decrease in smoking. But they are increasing in young adults, especially young, never-smoking women. The reason is not understood and remains under study at this time.

Types you may hear about include:

• Non-small cell lung cancer: Subtypes of non-small cell lung cancer (responsible for around 80-85% of lung cancers) include lung adenocarcinoma, squamous cell carcinoma of the lungs, and large cell lung cancer.¹³

• Small cell lung cancer: Small cell lung cancer accounts for around 15% of lung cancers and is more likely to occur in people who have smoked.¹⁴

• Mesothelioma: Mesothelioma is a cancer of the pleural mesothelium, the lining surrounding the lungs. It is strongly linked with exposure to asbestos.¹⁵

Digestive System Cancers

Digestive tract cancers may occur anywhere from the mouth to the anus. Most of these cancers are adenocarcinomas, with squamous cell carcinomas occurring in the upper esophagus and most distant portion of the anus. Types include:

• Esophageal cancer: The most common form of esophageal cancer has changed in recent years. Whereas squamous cell esophageal cancer (often related to smoking and drinking) was once the most common form of the disease, it has been surpassed by esophageal adenocarcinoma (often related to long-standing acid reflux).¹⁶

• Stomach cancer: Stomach cancer is uncommon in the United States, but is a common type of cancer worldwide.

• Pancreatic cancer: Pancreatic cancer is less common than some other cancers, but is the fourth most common cause of cancer-related deaths in both men and women.¹² It is most often diagnosed in the later stages of the disease, when surgery is unfortunately no longer possible.

• Liver cancer: Cancer metastatic to the liver is much more common than primary liver cancer. Risk factors for liver cancer include alcohol abuse and chronic infections with hepatitis B or C.¹²

• Colon cancer: Colon cancer is often referred to as colorectal cancer and includes both cancers of the rectum and the upper colon. It is the third leading cause of cancer deaths in both men and women.¹²

• Anal cancer: Anal cancer differs from colon cancer both in treatments and causes. Studies now show that 91% of all anal cancers are associated with HPV virus, the majority linked to just two subtypes (HPV-16 and HPV-18).¹⁷

 How Human Papillomavirus (HPV) Is Treated

Urinary System Cancers

The genitourinary system involves the kidneys, the bladder, the tubes connecting the kidneys and bladder (called the ureters), and the urethra (the passageway out from the bladder). This system also includes structures such as the prostate gland. Types include:

• Kidney cancer: The most common types of kidney cancer include renal cell carcinoma (around 90% of cases),¹⁸ transitional cell carcinoma, and Wilms' tumor in children.

• Bladder cancer: Roughly half of bladder cancers are caused by tobacco exposure.¹² Those who work with dyes and paints are also at higher risk.

• Prostate cancer: Prostate is the second leading cause of cancer death in men, but now has a very high five-year survival rate.¹²

Reproductive System Cancers

Reproductive organ cancers may occur in men and women. Ovarian cancer is the fifth most common cause of cancer deaths in women, and though curable in the early stages, is often diagnosed when it has already spread. Types include:

• Testicular cancer

• Ovarian cancer (including germ cell tumors)

• Uterine cancer (also called endometrial cancer)

• Fallopian tube cancer

• Cervical cancer

Endocrine Cancers

The endocrine system is a series of glands that produce hormones and, as such, may have symptoms of an over- or underproduction of these hormones.

Most endocrine cancers, with the exception of thyroid cancer, are fairly rare. A combination of different endocrine cancers may run in families and is referred to as multiple endocrine neoplasia, or MEN.¹⁹

The incidence of thyroid cancer is increasing in the United States at a higher rate, but the survival rate for many of these cancers also is high.

Bone and Soft Tissue Cancers

In contrast to primary bone and soft tissue cancers, which are uncommon, cancer that is metastatic to bone is common. Bone cancer, either primary or metastatic, often presents with symptoms of pain or of a pathologic fracture—a fracture that occurs in a bone that is weakened by the presence of tumor.²⁰ Types include:

• Osteosarcoma

• Kaposi's sarcoma: Kaposi's sarcoma is a soft tissue cancer often seen in people with HIV/AIDS.

• Ewing's sarcoma: Ewing's sarcoma is a bone cancer that primarily affects children.

Blood-Related Cancers

Blood-related cancers include both those involving blood cells and those involving solid tissue of the immune system, such as lymph nodes.

The risk factors for blood-related cancers differ somewhat from solid cancers in that environmental exposures as well viruses, such as the Epstein-Barr virus, play a significant role.

Blood-related cancers are the most common cancers in children. They include:²¹

• Hodgkin lymphoma

• Non-Hodgkin lymphoma

• Acute lymphocytic leukemia

• Chronic lymphocytic leukemia

• Acute myelogenous leukemia

• Chronic myelogenous leukemia

• Myeloma

Skin Cancers

Skin cancers are often separated into two primary groups: melanoma and non-melanoma. While non-melanoma skin cancers are much more common, melanomas are responsible for most skin cancer deaths.²²

Examples of skin cancers include:

• Basal cell carcinoma

• Squamous cell carcinoma of the skin

Skin cancer is the most common type of cancer overall in the United States, according to the Centers for Disease Control and Prevention (CDC).²³

Other Classification Methods

In addition to grouping cancers in the above ways, tumors are often classified by:

• Tumor grade: Grade is a measure of the aggressiveness of a tumor. A grade 1 tumor is less aggressive, and the cells may closely resemble the normal cells in which the cancer began. A grade 3 tumor, in contrast, is usually more aggressive, and the cells look very different than normal cells.

• Tumor stage: Tumors are staged in different ways, but many are given a number between 1 and 4, with 4 being the most advanced stage of the cancer.

• Non-hereditary cancer vs. hereditary cancer: Some cancers are referred to as hereditary cancers. For example, around 5-10% of breast cancers are referred to as such.²⁴ There is much overlap, and genetics play a role in many cancers.

• DNA/molecular profiles: As our understanding of genetics improves, tumors are more frequently being classified in terms of genetic profile. For example, some lung cancers have EGFR mutations, while others have ALK rearrangements.

 Genetic Tests for Cancer

A Word From Verywell

There are many types of cancer in addition to those mentioned here. With an increased understanding of genetics, it's likely that the classification of cancers will improve significantly over the next decade.

The treatments for, and survival from, cancer have been improving in recent years, too. Ask your healthcare provider if you have questions about a specific cancer.

If you are diagnosed with a rare cancer, it may be worth asking for a second opinion at one of the large National Cancer Institute-designated cancer centers. These larger centers are more likely to have oncologists on staff who take a special interest in less common—but no less important—cancers.