What Are the Rarest Cancers?

Medically Reviewed on 6/9/2022
Rare cancer can be challenging for patients, doctors, and scientists due to the limited information available.

Rare cancer occurs in fewer than 15 out of 100,000 people every year.

Some of the characteristics of the rarest cancer are:

  • Difficult to prevent, diagnose, and treat than the more common cancers
  • Research is difficult because there are a few cases
  • They make up just over a quarter of all cancers
  • Rare cancer can cause a quarter of all cancer deaths
  • Finding a new treatment for a rare cancer is extremely challenging

Rare cancer chart

The rarest types of cancer are presented in the table below.

Table. Some of the rarest cancer and their occurrence, survival rate, and the body parts affected
Types of rare cancer Number of people affected every year The area of the body affected Symptoms Is it treatable? Survival rate
Hyalinizing clear cell carcinoma of minor salivary gland tumor 51 cases
  • Salivary glands
  • Tongue
  • Palate
  • Swelling
  • Difficulty swallowing
  • Ulceration
Treatable with surgery High survival rate
Heart cancer Reported one to two patients per year Heart
  • Heart failure
  • Irregular heartbeat
Yes The 5-year survival rate is 17 percent
Ewing’s sarcoma 3 per 1 million people
  • Bone or soft tissue of the pelvis
  • The femur (thigh bone)
  • The humerus (upper arm bone)
  • The ribs
  • The mandible (jaw)
  • The clavicle (collar bone)
  • A lump near the skin that feels warm and soft to the touch
  • Persistent low fever
  • Limping because the legs hurt
  • Bone pain that worsens while exercising or during the night
  • Broken bones that happen without an injury
  • Weight loss
  • Feeling tired constantly
  • Paralysis or loss of bladder control if the tumor occurs near the spine
Yes The 5-year survival rate for tumors that have not spread is about 70 percent and 30 percent for tumors that have spread to other locations
Thymic carcinoma 400 cases per year Thymus gland
  • A cough that does not go away
  • Shortness of breath
  • Chest pain
  • A hoarse voice
  • Swelling in the face, neck, upper body, or arms
Yes The 5-year survival rate is between 30 and 50 percent
Wilms’ tumor 1 in 10,000 children each year (about 500 to 650 in the United States) Kidneys
  • An abdominal mass
  • Abdominal swelling
  • Abdominal pain
  • Fever
  • Blood in the urine
  • Nausea or vomiting or both
  • Constipation
  • Loss of appetite
  • Shortness of breath
  • High blood pressure
Yes High: The 5-year survival rate is about 90 percent
Merkel cell carcinoma About 2000 cases in the United States each year Skin cancer typically found on the face, head, or neck
  • Painless, shiny lumps of the skin
  • Red, pink lumps
Yes The 10-year survival rate of about 57 percent (about 71 percent if caught early)
Glioblastoma (a type of brain tumor) 0.59 to 5 cases per 100,000 people Found in the brain
  • Headaches
  • Nausea
  • Memory loss
  • Difficulty balancing 
  • Vision problems
Yes Low: People live less than a year after diagnosis
Hepatoblastoma 50 to 75 new cases Liver
  • Pain or swelling in the abdomen
  • Loss of appetite
  • Weight loss
Yes The five-year survival rate in children is 81.5 percent
Male breast cancer About 2550 cases each year in the United States Male breast tissue
  • Redness or sores on the chest or nipple area
  • An inverted nipple (nipple is pulled inward)
  • Discharge from the nipple
  • Redness or scaling of the skin covering the breast
  • Thickening of the breast tissue
  • Nipple pain
  • Enlarged lymph nodes under the arm
Yes The five-year survival rate is 84 percent
Fibrosarcoma 5 per 1 million A type of soft tissue cancer that begins in fibrous tissue, which holds bones, muscles, and other organs in place
  • Pinched nerve
  • Unusual swelling
  • Unintended weight loss
  • A painful soft lump
Yes The five-year survival rate is 40 to 60 percent


Skin Cancer Symptoms, Types, Images See Slideshow

Why is rare cancer challenging?

Rare cancer can be challenging for patients, doctors, and scientists due to the limited information available.

For patients

  • The time taken to identify any symptoms and the time taken by the doctor to identify the type of cancer can be time-consuming.
  • Because there is limited information available on the rarest cancer, it would be difficult to find doctors who are aware of cancer and its treatment.
  • They might experience a dilemma if the doctors do not agree on how to treat cancer.
  • There might be a need to travel away from home to a distant place to get appropriate treatment for cancer.

For doctors

  • It would be difficult for them to explain to their patients the outcome of the disease and treatment modalities due to the limited information available.
  • They may have a lack of experience or training to treat this type of cancer.
  • Lack of availability of experts in rare cancer to whom they can ask their concerns or refer the patient.

For scientists

  • Due to lack of information, they may not be sure about drugs that could help treat this type of cancer.
  • Lack of animal or cell models of rare cancer to test their ideas.
  • Insufficient tumor samples from rare cancer patients are available to move further in the research.
  • Finding enough patients with rare cancers is difficult. They are extremely important to execute the ideas about the drugs that could probably treat rare cancer.
Medically Reviewed on 6/9/2022
Image Source: iStock image

American Cancer Society. Rare Cancers, Cancer Subtypes, and Pre-Cancers. https://www.cancer.org/cancer/rare-cancers.html#F-L

National Cancer Institute. Rare cancer. https://www.cancer.gov/publications/dictionaries/cancer-terms/def/rare-cancer