Chemotherapy-Induced Bleeding
Bleeding linked to low platelets during cancer treatment
Quick Facts
- Type: Treatment-related blood disorder
- Main cause: Low platelet count (thrombocytopenia)
- Common signs: Bruising, nosebleeds, bleeding gums
- Emergency: Heavy or uncontrolled bleeding, blood in vomit or stool
Overview
Chemotherapy-induced bleeding is abnormal bruising or bleeding that develops because cancer treatment affects the bone marrow, where blood cells are made. Many chemotherapy drugs temporarily reduce the number of platelets, the cell fragments that help blood clot. When platelets fall low enough, a condition called thrombocytopenia, the blood does not clot as well and bleeding can occur more easily.
This is one of the more common side effects of chemotherapy. It is usually temporary and improves as the bone marrow recovers between treatment cycles, but it needs to be monitored closely because severe bleeding can be dangerous. Care teams check blood counts regularly to catch low platelets early.
Symptoms
Signs of chemotherapy-related bleeding range from minor to serious.
- Easy or unexplained bruising
- Tiny red or purple dots on the skin (petechiae)
- Nosebleeds and bleeding gums
- Heavier or longer menstrual periods
- Blood in urine or stool, or black, tarry stools
- Prolonged bleeding from small cuts
Serious warning signs include vomiting blood or material that looks like coffee grounds, coughing up blood, a sudden severe headache, confusion, or heavy bleeding that will not stop. These require emergency care.
Causes
The main cause is a drop in platelets caused by the treatment.
- Bone marrow suppression: Chemotherapy targets rapidly dividing cells, including the marrow cells that produce platelets, lowering their numbers.
- Timing of the cycle: Platelet counts often reach their lowest point (the nadir) a week or two after a chemotherapy dose, then recover.
- The cancer itself: Some cancers affect the bone marrow or clotting and add to the risk.
- Other medications: Blood thinners, aspirin, and certain anti-inflammatory drugs can increase bleeding when platelets are already low.
Risk Factors
- Higher-dose or combination chemotherapy regimens
- Cancers that involve the bone marrow
- Previous radiation or chemotherapy
- Use of blood thinners, aspirin, or NSAIDs
- Other conditions that affect clotting or platelets
- Liver disease, which can reduce clotting factors
Diagnosis
The care team evaluates bleeding with blood tests and a review of symptoms.
- Complete blood count (CBC): Measures the platelet count and other blood cells to gauge bleeding risk.
- Clotting tests: Assess how well the blood is forming clots.
- Physical examination: Looks for bruising, petechiae, and sources of bleeding.
- Further tests: If bleeding is internal, imaging or endoscopy may be used to find the source.
Treatment
Treatment depends on how low the platelets are and how much bleeding is present.
- Monitoring and dose adjustment: The oncologist may delay, reduce, or change chemotherapy to let counts recover.
- Platelet transfusions: Given when counts are very low or there is significant bleeding.
- Medications: In some cases, drugs that stimulate platelet production may be used.
- Local measures: Pressure on a bleeding site, treating nosebleeds, and stopping medications that worsen bleeding.
Most cases improve as the bone marrow recovers between cycles. Severe or uncontrolled bleeding is treated as an emergency.
Prevention
- Attend all scheduled blood tests so low counts are caught early
- Avoid aspirin, NSAIDs, and blood thinners unless approved by your team
- Use a soft toothbrush and an electric razor to prevent cuts
- Take care to avoid falls, bruises, and injuries
- Avoid contact sports and activities with a high injury risk when counts are low
- Report any new bleeding or bruising to your care team promptly
When to See a Doctor
Contact your cancer care team right away for new bruising, frequent nosebleeds, bleeding gums, or blood in urine or stool. Seek emergency care immediately for:
- Bleeding that will not stop after applying pressure
- Vomiting blood or coughing up blood
- Black, tarry, or bloody stools
- Sudden severe headache, confusion, vision changes, or weakness, which can signal bleeding in the brain
- Dizziness, fainting, or a racing heartbeat
Frequently Asked Questions
Why does chemotherapy cause bleeding?
Many chemotherapy drugs suppress the bone marrow, where platelets are made. Platelets help blood clot, so when their numbers fall (thrombocytopenia), bleeding and bruising happen more easily. Counts usually recover between treatment cycles.
When are platelets lowest after chemotherapy?
Platelet counts often reach their lowest point, called the nadir, about one to two weeks after a chemotherapy dose, then gradually recover before the next cycle. Your team schedules blood tests around this to monitor your risk.
What bleeding signs are an emergency during chemo?
Seek emergency care for bleeding that will not stop, vomiting or coughing up blood, black or bloody stools, or a sudden severe headache with confusion or weakness. These can indicate serious or internal bleeding.
What can I do to prevent bleeding during treatment?
Avoid aspirin and anti-inflammatory drugs unless approved, use a soft toothbrush and electric razor, prevent falls and injuries, and avoid contact sports when counts are low. Keep all blood test appointments so low platelets are caught early.
Will the bleeding go away after chemotherapy ends?
In most people, platelet counts and bleeding risk return to normal as the bone marrow recovers after treatment. The timing depends on the drugs used and your overall health, so your team will continue to monitor your blood counts.
References
- National Cancer Institute (NCI). Bleeding and bruising during cancer treatment.
- American Cancer Society. Low platelet count (thrombocytopenia).
- MedlinePlus, U.S. National Library of Medicine. Bleeding during cancer treatment.
- Mayo Clinic. Thrombocytopenia (low platelet count).