A low platelet count is a common side effect of chemotherapy. If your platelet counts drops too low, your doctor may reduce, delay, or discontinue chemotherapy treatment.

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Platelets are special blood cells that help your blood clot. A low platelet count is medically known as thrombocytopenia.

If you have thrombocytopenia, you may have symptoms such as:

  • prolonged bleeding from small cuts
  • easy bruising
  • frequent nosebleeds or gum bleeding
  • heavy menstrual bleeding

You can develop thrombocytopenia for many reasons, including undergoing chemotherapy. When chemotherapy is the underlying cause, it’s called chemotherapy-induced thrombocytopenia.

A normal platelet count is usually considered between 150 and 450 billion platelets per liter of blood. Chemotherapy-induced thrombocytopenia is usually defined as a platelet count under 100 billion per liter.

This article will look at how chemotherapy affects your platelet count and how chemotherapy-induced thrombocytopenia is treated.

Chemotherapy (also referred to as chemo) drugs contain chemicals that destroy cancer cells or slow down their growth. These chemicals act broadly on all cells in your body that replicate quickly. The cells in your bone marrow that create platelets are particularly prone to damage from chemo.

A reduced platelet count is a common chemotherapy side effect. In a recent study, researchers found that 13% of more than 15,000 people with solid tumors developed thrombocytopenia within 3 months of starting chemo treatment.

Chemotherapy-induced thrombocytopenia is divided into grades based on its severity:

GradePlatelet count (billions per liter)
Grade 175–100
Grade 250–75
Grade 325–50
Grade 4less than 25

Chemotherapy regimens and platelet count

Many types of chemo drugs are used to treat cancer, and doctors often administer multiple drugs at the same time to target cancer cells in different ways.

Some drugs or combinations of drugs come with a higher risk of damaging your platelets than others.

In a 2020 study, researchers examined the rates of thrombocytopenia among 523 people undergoing treatment for a type of non-Hodgkin’s lymphoma called diffuse large B-cell lymphoma.

They reported the following rates:

Regimen nameDrugs includedPercentage of people who developed thrombocytopenia
ACVBP• cyclophosphamide
• doxorubicin
• vincristine
• bleomycin
• prednisone
CHOP• cyclophosphamide
• doxorubicin hydrochloride (Adriamycin)
• vinblastine
• prednisone
DHAP• dexamethasone
• high-dose cytarabine
• cisplatin
EPOCH• cyclophosphamide
• etoposide
• doxorubicin
• vinblastine
• prednisone
GDP• gemcitabine
• dexamethasone
• cisplatin
GEMOX• gemcitabine hydrochloride
• oxaliplatin
ICE• ifosfamide
• carboplatin
• etoposide

If you develop thrombocytopenia, future doses of chemotherapy may be:

  • reduced
  • delayed
  • discontinued

There’s no universally agreed-on minimum platelet count for when doctors decide to delay or discontinue chemotherapy. Your doctor will use their best judgment based on your symptoms and the results of your blood tests to decide when you may be able to resume treatment.

Your doctor may want to administer chemo and radiation therapy with caution at platelet levels under 100 billion per liter. A platelet count of less than 50 billion per liter of blood can complicate surgery.

You usually wouldn’t have bleeding complications or need platelet transfusion unless your platelet count drops under 25 billion per liter.

Most standard combinations of chemo drugs have a low risk of thrombocytopenia that is severe enough to limit the dosage of chemotherapy. Platelet levels often return to normal within 4–6 days.

Symptoms are often worse 10–14 days after receiving your first session of chemotherapy.

Learn more about low platelet symptoms.

You may need a platelet transfusion if your platelet count drops severely low or if you have bleeding complications.

A platelet transfusion involves injecting platelets from donors into your blood. Unlike red blood cells, platelets don’t have blood types so you can receive platelets from almost anybody. Often platelets in transfusions come from 6–10 units of donated platelets.

When do doctors recommend platelet transfusions?

Doctors usually only recommend platelet transfusions if your platelet count drops severely low or if you’re having reoccurring bleeding complications.

Some chemo regimens are more likely to drop your platelet low enough for you to require a platelet transfusion than others. Here are some examples of low platelet rates based on different cancer regimens:

ibritumomab tiuxetannon-Hodgkin’s lymphoma30%
ICEnon-Hodgkin’s lymphoma23%
gemcitabine and cisplatinunknown originating location15%
gemcitabine and cisplatinnon-small cell lung cancer9%
topotecansmall cell lung cancer5.8%

Medications for low platelet count

No drugs have been FDA-approved to specifically treat chemotherapy-induced thrombocytopenia.

Drugs called antifibrinolytic agents are currently being tested for treatment of thrombocytopenia, but the results and benefits aren’t yet known. These drugs help your blood clot by breaking down a protein called fibrin.

Supporting treatment

Treating other causes of thrombocytopenia may help raise your platelet count. Treatment might consist of:

  • stopping certain antibiotics
  • treating underlying infections
  • controlling genetic diseases linked to problems with blood clotting
  • making dietary improvements

Taking steps to avoid bleeding or bruising may help reduce thrombocytopenia complications. Steps you can take include:

  • flossing your teeth gently
  • using a soft bristle toothbrush
  • using moisturizers and lip balm to prevent skin dryness or cracking
  • avoiding activities with a high risk of injury, such as contact sports
  • taking care when using knives, razors, or sharp objects
  • wearing shoes and socks to protect your feet
  • removing clutter on the floor to reduce the risk of tripping or falling

Chemicals in chemotherapy drugs can damage healthy cells in your body that replicate quickly. The cells in your bone marrow that produce platelets are particularly vulnerable to damage from chemo.

A low platelet count is a common side effect of chemo. Platelet counts often return to normal within 4–6 days. If your platelet count drops too low, your doctor may reduce, delay, or discontinue chemo treatment.