Is sickle cell a cancer?

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Blood cancer is a term that describes several cancer types that affect the blood, bone marrow, or lymphatic system. It occurs when something goes wrong with the development of blood cells.

Although there are abnormalities within blood cells in both blood cancer and SCD, SCD is not cancer. It is a disorder of the red blood cells. Some other differences between blood cancers and SCD are below:

Causes

Leukemia, lymphoma, and myeloma are common types of blood cancer.

• Leukemia: This condition involves the bone marrow producing excessive amounts of abnormal white blood cells.
• Lymphoma: This occurs when lymphocytes — a type of white blood cell — form a mutation and multiply rapidly.
• Myeloma: This condition develops when cancerous plasma cells accumulate in the bone marrow.

SCD involves a change in the gene that tells the body to make hemoglobin. Hemoglobin delivers oxygen to the organs and tissues and transports carbon dioxide back to the lungs.

The abnormal hemoglobin associated with SCD causes red blood cells to become rigid, sticky, and distorted into a C-shape. SCD does not typically affect the shape or function of white blood cells.

Learn more about sickle cell disease.

Blood cell lifespan

Cancer cells do not mature and die in the same way as standard cells. They continue to reproduce other abnormal cells that accumulate and eventually overwhelm the production of healthy cells.

Unlike cancer cells, sickle cells die early, causing an ongoing shortage of red blood cells. Typical red blood cells live around 90–120 days, but sickle cells only live for 10–20 days.

Genetic influence

Issues in a person’s DNA cause blood cancer, but that does not mean it occurs because the genes for blood cancer pass from parent to child.

Evidence suggests that having a family member with blood cancer may slightly increase a person’s risk for the condition. But it is not clear whether this is due to a genetic mutation that passes down or for another reason. According to the American Cancer Society (ACS), only about 5–10% of all cancers have a strong link between the disease and gene mutations inherited from a parent.

People can inherit SCD, meaning that it runs in families. People with SCD inherit two faulty hemoglobin genes — one from each parent. They have the condition from birth. If a person inherits one faulty hemoglobin gene and one standard hemoglobin gene, they have sickle cell trait (SCT). A person with SCT is usually healthy but can pass the faulty gene to their children.

Learn more about SCT.

Prevalence

Around 1.5 million people in the U.S. have or are in remission from blood cancers. Although millions of individuals worldwide have SCD, it is a relatively rare blood disorder, affecting approximately 100,000 people in the U.S.

SCD treatment aims to reduce pain episodes, relieve symptoms, and prevent complications with lifestyle changes, medications, and other strategies.

Doctors may suggest applicable lifestyle changes to prevent or reduce pain, such as:

• drinking enough water
• maintaining a comfortable temperature
• avoiding exposure to high altitudes, such as flying or mountain climbing
• avoiding exposure to low oxygen levels, such as excessive exercise or mountain climbing
• quitting smoking

Treatments for SCD may include:

• Voxelotor (Oxbryta): This medication prevents red blood cells from becoming a sickle shape and sticking together, lowering the risk of anemia and improving blood flow.
• Crizanlizumab (Adakveo): This drug prevents blood cells from sticking to the walls of the blood vessels and causing a blockage to blood flow, which reduces inflammation and periodic episodes of extreme pain called pain crises.
• Hydroxyurea (Droxia): This medication reduces the frequency of pain crises, improves anemia, and decreases the need for transfusions.
• L-glutamine oral powder (Endari): This drug reduces the frequency of pain crises and hospital admissions.
• Over-the-counter pain relief: Acetaminophen (Tylenol) or ibuprofen (Advil) can help treat mild to moderate pain. A doctor may prescribe stronger pain relief medications called opioids for severe pain.
• Penicillin: Some people may require penicillin throughout their lives to lower their chances of serious infection in the bloodstream.
• Blood transfusions: Some people may receive transfusions from a donor, such as:
  • acute transfusions
  • red blood cell transfusions
  • ongoing blood transfusions to prevent complications associated with SCD
• Stem cell transplant: This procedure replaces bone marrow affected by SCD with healthy bone marrow from a donor.

Some of the treatments for SCD are similar to those for blood cancers. For example, hydroxyurea is an antimetabolite drug that treats chronic myeloid leukemia. Antimetabolites are a form of chemotherapy drug that interferes with the division and functioning of cells.

People with blood cancers may also have a stem cell transplant to replace affected bone marrow with healthy bone marrow.

Most infants do not experience SCD symptoms until they are 5–6 months old. The symptoms of SCD can vary between people and over time. They may include the following:

• Painful episodes: Severe pain that lasts for days or weeks can occur when sickle cells block the blood vessels to a particular area of the body, commonly the limbs or back.
• Frequent infections: People with SCD are more likely to develop infections that range from mild, such as colds, to severe, such as meningitis.
• Anemia: Most people with SCD have a shortage of red blood cells, known as anemia. A red blood cell shortage reduces the oxygen circulating in the body and causes fatigue.
• Swelling of hands and feet: The sickle-shaped cells block blood circulation, causing the hands and feet to swell.
• Vision problems: Sickle cells clogging the tiny blood vessels in the eyes can cause damage to the retina, the part of the eye that processes visual images. This can lead to vision difficulties.
• Delayed growth: Red blood cells provide the oxygen and nutrients children need to develop. A shortage of healthy red blood cells may slow growth and delay puberty in teenagers.

The outlook for a person with SCD depends on the type of SCD, the treatments they receive, and any complications they may experience.

Overall, people with SCD tend to have a shorter life expectancy than the average person by around 20–30 years. However, with ongoing advances in treatments, people with SCD live longer and have an improved quality of life.

SCD is a red blood cell disorder where the red blood cells become crescent-shaped, stiff, and sticky. It is a noncancerous condition. However, some of the treatments for SCD also treat blood cancers such as leukemia, lymphoma, and myeloma.

Healthy cells tend to live up to 120 days, but sickle cells only live for around 10–20 days. Where sickle cells tend to die early, causing a shortage of red blood cells transporting oxygen around the body, cancer cells have a prolonged existence and multiply rapidly.

People with SCD typically have a decreased life expectancy, but treatment advances prolong survival, reduce complications, and improve quality of life.