Low Platelet Count (Thrombocytopenia) During Cancer Treatment

Thrombocytopenia in people with cancer is commonly caused by chemotherapy. Defined as a decreased number of platelets in the blood, it can sometimes be serious, with some chemotherapy drugs more likely than others to result in low counts. A low platelet count can, in turn, result in bleeding and/or the need to delay chemotherapy.

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 with others, such as tumors that spread to the bone marrow or even antibodies your own body may produce against your platelets, potentially contributing as well.

A 2019 study looking at thrombocytopenia in people with cancer in the U.S. found that the incidence is high and is associated with substantial complications and cost.

This article covers symptoms and causes of thrombocytopenia during chemotherapy and how it can be treated.

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: These are red spots on your skin (most common on the lower legs), that do not turn white when you press on them with your fingers.
• 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, bleeding into the brain, chest, or abdomen may result in symptoms of shock, guarding (not wanting abdomen touched), coughing up blood, or neurological symptoms such as headaches, one-sided weakness, visual changes, or loss of balance.
• Joint and muscle pain
• Severe headaches
• Feeling dizzy or weak

Diagnosis

Your healthcare provider 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 450,000 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.

Evaluating Causes

As noted earlier, a low platelet count is sometimes due to more than one cause during cancer treatment. Looking at platelet counts over time (serial platelet measurements) can often be helpful in understanding whether chemotherapy alone is the culprit.

One of the indices given on a CBC, mean platelet volume, describes the average size of platelets in the blood and is also helpful in evaluating other causes of thrombocytopenia.

Causes During Cancer Treatment

The most common cause of thrombocytopenia in people with cancer is bone marrow suppression related to chemotherapy. Chemotherapy destroys rapidly dividing cells, such as those in the bone marrow which become platelets. This is usually temporary.

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) 

Other Causes

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 (Hodgkin lymphoma) and chronic lymphocytic leukemia.
• Infections: Especially viral infections
• Other medications that can cause low platelets: Such as the antibiotic vancomycin, and anti-viral medications.
• Tumor has 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

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 healthcare provider 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 preventively (for those with a low or expected low platelet count but who are not bleeding). This type of treatment is considered temporary, as the platelets from a transfusion only last for around three days.

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 Platelet Formation

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, and there is currently little evidence to support their routine use.

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

Currently there are no 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. Eating a healthy diet rich in these nutrients is important as you rebuild your platelet count after chemotherapy.

Most oncologists believe that using 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 healthcare provider, there are several things you can do yourself to reduce your risk of complications from a low platelet count.

Avoid Irritation and Injuries

To avoid situations that could lead to bleeding:

• 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.
• Be careful with cutting fingernails and toenails. Nails should be cut straight across and kept relatively to short to avoid tears that could potentially bleed. Many oncologists recommend avoiding manicures and pedicures during chemotherapy both due to the risk of bleeding and the risk of infection.
• 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 healthcare provider may recommend a stool softener or other medications for you during chemotherapy to prevent this.
• Avoid situations where you could be injured. Take extra care when cooking, gardening, or using scissors or tools. Avoid contact sports. Pets should have nails trimmed. Avoid animals that may bite. Special precautions should be taken with pets during chemotherapy to reduce your risk of infection as well.

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. 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.

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.