Low Platelet Count (Thrombocytopenia) During Cancer Treatment

Symptoms, Diagnosis, Treatments, and Coping

lab technician drawing blood to test for low platelets during chemotherapy
What is thrombocytopenia and what should you know about this condition during chemotherapy?. istockphoto.com

Thrombocytopenia is defined as a decreased number of platelets in the blood. A low platelet count can, in turn, result in bleeding and/or the need to delay chemotherapy. Thrombocytopenia is usually defined as less than 150,000 platelets per cubic millimeter of blood on a complete blood count, although significant bleeding does not usually occur until the level drops below 20,000 or even 10,000. Symptoms may include easy bruising, joint and muscle pain, and bleeding, such as heavy menstrual periods, nosebleeds, and rectal bleeding. Treatments depend on the level and the timing in relation to chemotherapy and may include transfusions or medications to stimulate platelet production. It's important to note that chemotherapy is only one potential cause of a low platelet level during cancer treatment, such as tumors that spread to the bone marrow or even antibodies your own body may produce against your platelets.

While less often a problem than issues such as a low white blood cell count, a low platelet count can sometimes be serious, with some chemotherapy drugs more likely than others to result in low counts. Let's look at what you need to know about thrombocytopenia and what you can do yourself to reduce your risk of complications.

Signs and Symptoms

It's common for people to learn that they have a low platelet count based on blood tests alone, and before any symptoms occur. When signs and symptoms are present, they may include:

  • Easy bruising: Large, reddish blue patches known as ecchymoses may occur
  • Petechiae: Red spots on your skin (most common on the lower legs), that do not turn white when you press on them with your fingers
  • Joint and muscle pain
  • External bleeding: Bleeding may occur from the nose (nosebleeds), the mouth (especially with brushing teeth,) the rectum (black or bloody bowel movements), the stomach (vomiting blood or coffee-appearing material), or the vagina (often as heavier than normal periods)
  • Internal bleeding: One of the most serious complications of thrombocytopenia is internal bleeding, into the brain, chest, or abdomen. Internal bleeding may result in symptoms of shock, guarding (not wanting the abdomen to be touched), coughing up blood, or neurological symptoms such as headaches, weakness on one side of the body, visual changes, or loss of balance.

Diagnosis

Your doctor will order a complete blood count (CBC) before and after chemotherapy to see if you have a low platelet level.

Normal Range

A normal platelet count (thrombocyte count) is usually defined as having 150,000 to 400,000 platelets per cubic millimeter of blood. A level below 150,000 is considered abnormal, or thrombocytopenia.

Low Levels: Mild and Severe

Most of the time a level of platelets greater than 50,000 is not associated with any major problems. A level of 10,000 to 20,000 may sometimes cause bleeding, but most often counts can drop to 10,000 or less before causing significant bleeding.

In general, levels less than 10,000 are usually treated (most often with a platelet transfusion) but levels less than 20,000 may also be treated, especially if associated with a fever. For those going through chemotherapy, levels of even 50,000 to 100,000 may result in a delay of chemotherapy. It's important to note that everyone is different, and the same count in two different people could be worrisome for one and of little concern in another.

Causes During Cancer Treatment

The most common cause of thrombocytopenia in people with cancer is bone marrow suppression related to chemotherapy. (See other causes below.) Chemotherapy destroys rapidly dividing cells, such as those in the bone marrow which become platelets. In addition to thrombocytopenia, bone marrow suppression from chemotherapy may result in a low red blood cell count (chemotherapy-induced anemia) and a low level of the type of white blood cells known as neutrophils (chemotherapy-induced neutropenia) which defend against bacterial infections.

Chemotherapy Drugs

Many chemotherapy drugs do not affect platelet levels to a degree which is significant enough to require treatment, but some drugs are much more likely than others to reduce counts.

Drugs commonly associated with thrombocytopenia include:

  • Platinum-based drugs such as Paraplatin (carboplatin) and Platinol (cisplatin)
  • Gemzar (gemcitabine)
  • Taxol (paclitaxel) 

How Long do Low Counts Last?

Thrombocytopenia related to chemotherapy is often a short term problem. Platelet levels begin to drop around one week after a chemotherapy session and reach the lowest level (the nadir) at around 14 days following an infusion.

Platelets in the bloodstream live approximately 8 to 10 days and are rapidly replenished. When levels are low, they most often return to normal in around 28 to 35 days (unless another chemotherapy infusion is received), but may take up to 60 days to reach pre-treatment levels.

Other Causes of Thrombocytopenia in People with Cancer/Different Diagnosis

There are several reasons why platelet counts may be lower in people with cancer in addition to chemotherapy. These may include:

  • Immune thrombocytopenia (ITP): Immune thrombocytopenia occurs when your body makes antibodies against your own platelets. This is most common with cancers such as Hodgkin disease and chronic lymphocytic leukemia.
  • Infections, especially viral infections
  • Other medications which can cause low platelets such as the antibiotic vancomycin, and anti-viral medications
  • Tumor spread to the bone marrow (most commonly lymphomas, breast cancer, and lung cancer)
  • Thrombotic microangiopathy (a condition in which the inner cell lining of blood vessels is damaged which sometimes occurs with chemotherapy drugs such as Mitomycin C and gemcitabine.)

Treatment/Prevention

It's important to first determine the cause of your thrombocytopenia as there could be different reasons for your low platelet level which are treated in different ways. For example, if it is related to chemotherapy drugs, treatment may include delaying chemotherapy, whereas if it related to immune causes, steroids may be part of the recommended treatment.

Depending upon the level of your platelets, and whether or not you have any symptoms, your doctor may recommend treatment to raise your platelet count. Options include:

Platelet transfusions

Platelet transfusions are the most common method of treating thrombocytopenia, especially short-term thrombocytopenia related to chemotherapy drugs. Transfusions can be used as a therapy (to increase platelets in those who are actively bleeding) or preventatively (for those with a low or expected low platelet count but who are not bleeding). The most common side effect is a temporary fever. Rare side effects can include transfusion reactions or transmission of infections such as hepatitis.

Delaying chemotherapy

Delaying chemotherapy, or adjusting the dose may sometimes be necessary.

Medications that stimulate the formation of platelets

Medications are sometimes used to stimulate the bone marrow to make more platelets, though these are used infrequently in people who have thrombocytopenia due to chemotherapy. The drug most commonly used is Neumaga (oprelvekin), though the medications Nplate (romiplostim) and Promacta (eltrombopag) are sometimes used, though approved for low platelet counts due to autoimmune conditions.

Clinical trials

Clinical trials are ongoing, looking at other methods to lower the risk of thrombocytopenia during chemotherapy.

Complementary and Alternative Treatments

There are not currently any alternative treatments or dietary supplements that significantly improve platelet counts. That said, vitamins such as vitamin B12 and folate, and minerals such as iron are needed to produce healthy platelets, and eating a healthy diet rich in these nutrients is important as you rebuild your platelet count after chemotherapy. Most oncologists believe that dietary sources of these and other nutrients is the way to go, as some vitamins and minerals may interfere with chemotherapy.

Coping

In addition to any treatment recommended by your doctor, there are several things you can do yourself to reduce your risk of complications from a low platelet count.

Avoid Irritation and Injuries

  • Use a gentle toothbrush. Many oncologists recommend that you avoid using dental floss as well, but this has not yet been proven to help.
  • Use an electric razor to avoid cuts.
  • Blow your nose gently.
  • Try not to become constipated, and if you do, avoid straining or using suppositories. Some pain medications, as well as dietary changes, can cause constipation, and your doctor may recommend a stool softener or other medications for you during chemotherapy to prevent this.
  • Avoid situations where you could be injured or otherwise hurt yourself. Take extra care when using scissors, while cooking, and using tools. Avoid contact sports.

Avoid Medications That Can Increase Bleeding

There are several categories of medications that can increase bleeding, and hence, be additive with a low platelet count from chemotherapy. Certainly blood thinners, such as anticoagulants and anti-platelet drugs can be a problem. Non-steroidal anti-inflammatory medications such as Advil (ibuprofen) as well as aspirin also raise risk. It's important to note that many over-the-counter drugs as well as dietary supplements may increase bleeding as well, and it's important to talk to your oncologist about any of these preparations before using them.

Limit Alcohol Use

Alcoholic beverages can increase bleeding time. Drinking in excess also increases the risk of injuries that could lead to bleeding.

When to Call the Doctor

You should let your doctor know if you develop any of the signs or symptoms of thrombocytopenia discussed above. Call her immediately if you have bleeding that you are unable to stop, severe abdominal or chest pain, a new headache, blurred vision or weakness.

A Word From Verywell

Low platelet counts due to chemotherapy can often be managed conservatively, that is, by paying attention to symptoms and avoiding things that could risk bleeding. At times, however, thrombocytopenia will need to be treated. Being aware of your lab results, and keeping careful records, can help you be your own advocate in your care and recognize concerns before they become a problem.

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