Rare types of cancer, such as chronic myeloid leukemia and Ewing sarcoma, affect fewer than 15 people per 100,000 each year. Rare cancers can affect any part of the body and have different risk factors, symptoms, and outlooks.

You may be familiar with some of the most common types of cancer. According to the American Cancer Society, these include lung cancer, breast cancer, prostate cancer, and colorectal cancer.

However, some cancers are much rarer. The National Cancer Institute defines rare cancer as a cancer that affects fewer than 15 per 100,000 people each year.

Many cancers are rare. In this article, we touch on just a few of the rarest types of cancer that you may or may not have heard of.

Language matters

You’ll notice that the language used to share stats and other data points is pretty binary, fluctuating between the use of “male” and “female” or “men” and “women.”

Although we typically avoid language like this, specificity is key when reporting on research participants and clinical findings.

Unfortunately, the studies and surveys referenced in this article didn’t report data on, or include, participants who were transgender, nonbinary, gender nonconforming, genderqueer, agender, or genderless.

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Adrenal cortex carcinoma (ACC) affects the outer part of the adrenal gland, which makes hormones like cortisol. ACC is very rare, affecting approximately 1 person per 1 million in the United States. It’s more common in females than in males.

ACC can develop at any time, but mostly occurs in middle aged adults. People with certain inherited conditions like Li-Fraumeni syndrome and Beckwith-Wiedemann syndrome are at a higher risk.

ACC tumors can produce hormones in excess. As such, the symptoms of this cancer are often related to those of an excess of cortisol or sex hormones like estrogen or testosterone.

A 2022 study that analyzed survival rates in 47 people with ACC found that the median overall survival was 3 to 4 years. Survival rates were reduced to 15 months for those with advanced or metastatic ACC.

The table below shows the 5-year relative survival rates for all adrenal cancers (ACC is a type of adrenal cancer):

Stage of cancer5-year relative survival rate

About 5-year survival rates

A 5-year survival rate is the percentage of people with a certain type and stage of cancer that are alive 5 years after diagnosis.

The Surveillance, Epidemiology, and End Results (SEER) database of the National Cancer Institute uses three different stages:

  • Localized means that the cancer is still limited to the organ or tissue it started in.
  • Regional is when the cancer has spread to nearby tissues or lymph nodes.
  • Distant means that the cancer has spread to other parts of the body, such as the lungs, bones, or liver. This is typically referred to as metastatic or stage 4 cancer.

The 5-year survival rates are only statistics. They don’t account for individual factors like age and overall health. They also don’t always reflect recent advances in cancer treatment.

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Chronic myeloid leukemia (CML) is a slow growing type of leukemia that affects myeloid stem cells that eventually become blood cells like neutrophils.

Even though it’s one of the four main types of leukemia, CML is rare. In 2018, it was estimated to occur in 1 out of 100,000 people globally.

The risk of CML increases with age, and it’s also more common in males. Previous exposure to radiation is the only other known risk factor.

Symptoms of CML can include:

  • weakness and fatigue
  • fever
  • night sweats
  • unintentional weight loss
  • bone pain
  • enlarged spleen, which can cause a feeling of fullness on your left side below your ribs

The overall 5-year survival rate for people with CML is 70.4%.

Ewing sarcoma is an aggressive type of bone cancer that mainly affects children and adolescents. Despite being the second most common type of bone cancer in this age group, it only affects 1 to 3 out of a million people each year.

Most cases of Ewing sarcoma are diagnosed in adolescents. This cancer is also slightly more common in males.

The symptoms of Ewing sarcoma can include pain and swelling in the area of the tumor. Other more general symptoms can include fatigue, fever, and unintentional weight loss.

The table below shows the 5-year relative survival rates for Ewing sarcoma.

Stage of cancer5-year relative survival rate

Eye cancer is any type of cancer that begins in the eye. Ocular melanoma is the most common type of eye cancer in adults, but only affects 5 out of 1 million people in the United States. Other eye cancers are less common and include:

The risks for eye cancer can depend on the specific type of cancer. For example, some risk factors for ocular melanoma include older age, a family history of melanoma, and having lighter colored skin or eyes.

General symptoms of eye cancer can include things like:

Survival rates for eye cancer can vary based on the type. The table below shows the 5-year relative survival rates for ocular melanoma, the most common eye cancer in adults.

Stage of cancer5-year relative survival rate

Gallbladder cancer starts in the gallbladder, which stores bile used for digestion. In the United States, it occurs in 1.4 out of 100,000 females and 0.8 out of 100,000 males.

Some of the known risk factors for gallbladder cancer include:

The symptoms of gallbladder cancer can include:

The table below shows the 5-year relative survival rates for gallbladder cancer.

Stage of cancer5-year relative survival rate

Hairy cell leukemia (HCL) is a type of slow growing leukemia that affects B cells, which are immune cells that make antibodies. In HCL, the affected cells appear “hairy” under a microscope.

HCL is more common in men and is estimated to affect 0.3 out of 100,000 males and 0.1 out of 100,000 females globally. The risk of HCL increases with age.

People with HCL typically have low blood counts, which can lead to anemia, an increased risk of infection, and easy bruising or bleeding. The spleen may also become enlarged, leading to abdominal swelling and pain.

When it’s treated, the 5-year event-free survival for HCL is about 90%. Some research has also found that people with HCL can have a typical life span with treatment.

Hepatoblastoma is a type of liver cancer that mainly affects children. Despite being the most common type of liver cancer in this age group, it’s still very rare. Hepatoblastoma affects 1.5 out of 1 million people each year.

While many cases of hepatoblastoma happen randomly, about one-third are associated with inherited conditions like Beckwith-Weidemann syndrome and familial adenomatous polyposis. A low birth weight also increases risk.

Symptoms of hepatoblastoma can include:

  • an abdominal lump that can be painful and continues to get larger
  • abdominal swelling
  • reduced appetite
  • unintentional weight loss
  • nausea and vomiting

Research has found that the overall 5-year survival for hepatoblastoma is 81.9%.

Kaposi sarcoma (KS) starts in cells that line your blood vessels. It’s caused by infection with a virus called Kaposi sarcoma-associated herpesvirus (KSHV). KS affects 6 out of 1 million people in the United States each year.

Throughout the world, there are many more people with KSHV than with KS. This is because the main risk factor for KS is a weakened immune system, which can happen due to living with HIV, receiving an organ transplant, or the natural process of aging.

The symptoms of KS can include:

  • skin lesions, which:
    • most often occur on the lower body and face, may be raised or flat, and are typically red, brown, or purple in color
    • can cause pain and swelling
  • mouth or throat lesions
  • lesions inside the body that may bleed or interfere with the functions of affected organs and tissues

The table below shows the 5-year relative survival rates for KS.

Stage of cancer5-year relative survival rate

Lip cancer is type of oral cancer that starts on the lips. In the United States, it affects 0.5 out of 100,000 people every year.

Some of the risk factors for oral cancers like lip cancer are:

People with lip cancer may have symptoms like:

The table below shows the 5-year relative survival rates for lip cancer.

Stage of cancer5-year relative survival rate

While breast cancer most often affects the breasts of females, it can also occur in the breasts of males. In 2017, the Centers for Disease Control and Prevention (CDC) found that this rare type of breast cancer affected 1.28 out of 100,000 males.

The factors that increase the risk of breast cancer in males include:

  • older age
  • a family history of breast cancer, especially if other fathers or brothers in the family have had it
  • certain gene mutations, like those in BRCA1 and BRCA2
  • previous radiation exposure
  • high estrogen levels
  • Klinefelter syndrome

The main symptom of breast cancer in males is a lump or bump in your breast that you can feel and that’s typically painless. Other symptoms can include:

  • changes to the skin of your breast, such as redness or dimpling
  • changes in the size or shape of your breast
  • pain or discharge from your nipple
  • a nipple that turns inward

The table below shows the 5-year relative survival rates.

Stage of cancer5-year relative survival rate

Retinoblastoma is a type of cancer that affects the retina of the eye in children. It’s the most common eye cancer in children, affecting 11 out of 1 million children younger than age 5 worldwide.

Retinoblastoma is caused by having a gene change that can be inherited. Because of this, having a family history of retinoblastoma puts a child at a higher risk of having this type of cancer.

The symptoms of retinoblastoma can include:

More than 90% of children with retinoblastoma can go into remission (meaning that cancer isn’t detectable and isn’t expected to return) with treatment. In fact, research has found that the 5-year survival rate is 96.3% when retinoblastoma impacts one eye and is 92.5% when both eyes are affected.

Vaginal cancer is cancer that starts in the vagina, which is the part of the female reproductive tract that connects the cervix to the outside of the body.

The CDC estimates that 0.6 out of 100,000 women in the United States received a vaginal cancer diagnosis in 2019.

The risk factors for vaginal cancer are:

  • older age
  • HPV infection
  • a history vaginal, vulvar, or cervical precancers
  • smoking
  • exposure to the drug diethylstilbestrol (DES)

Some of the symptoms of vaginal cancer are:

The table below shows the 5-year relative survival rates for vaginal cancer.

Stage of cancer5-year relative survival rate

There are many types of rare cancer. These cancers can occur in any part of the body and can vary in their associated risk factors, symptoms, and outlook.

Generally speaking, the outlook for any cancer is best when it’s diagnosed and treated early. It’s recommended that you talk with a doctor if you develop concerning symptoms that are persistent or continue to get worse.