What Cancer Causes Low Neutrophils?
Some cancers directly lower neutrophil levels by affecting the bone marrow, where these white blood cells form. Blood cancers such as leukemia and lymphoma are the most common examples. These cancers interfere with normal blood cell production, which can lead to neutropenia, a condition marked by low neutrophil counts.
Other cancers may also play a role, but the drop in neutrophils often comes from the treatments used to fight the disease. Chemotherapy and radiation can damage healthy bone marrow cells along with cancer cells, making neutropenia a frequent side effect.
Definition of Symptom
Neutropenia means a low neutrophil count. Neutrophils are a type of white blood cell (WBC) that help the body fight infection. When these cells drop below normal levels, the body may struggle to respond to bacteria, fungi, or other harmful organisms.
Doctors measure this condition using the absolute neutrophil count (ANC). A normal ANC is usually between 2,500 and 5,000 cells per microliter of blood. Neutropenia is typically defined when the ANC falls below 1,500. Severe neutropenia is often considered when the ANC is below 500.
A complete blood count (CBC) is the most common blood test used to detect neutropenia. This test measures not only neutrophils but also other WBCs such as lymphocytes, monocytes, eosinophils, and basophils. A low neutrophil count may appear alongside a low total WBC count, which is called leukopenia. Key points include:
- Neutrophils: Main defenders against bacterial infection.
- Low Neutrophil Count: Increases risk of infection.
- CBC Test: shows neutrophil levels and other blood cell counts.
- Leukopenia vs. Neutropenia: Leukopenia means low total WBCs, while neutropenia refers specifically to neutrophils.
In many cancer patients, treatments like chemotherapy or radiation reduce the bone marrow’s ability to make new WBCs, leading to neutropenia. Certain blood cancers, such as leukemia or lymphoma, may also directly lower the neutrophil count. Some people may have mild neutropenia without frequent infections, while others may experience serious complications when the ANC drops very low.
Possible Causes/Diseases Condition
Low neutrophil counts, known as neutropenia, can result from several medical conditions and treatments. Some causes are temporary, while others are long-term or linked to serious diseases.
- Cancer and Cancer Treatments: Certain cancers, such as leukemia, lymphoma, and myeloma, directly affect the bone marrow, reducing its ability to produce neutrophils. Treatments like chemotherapy and radiation therapy also damage bone marrow cells, making neutropenia a common side effect of cancer care.
- Bone Marrow Disorders: Diseases that weaken or destroy bone marrow can lower neutrophil production. Aplastic anemia is one example, where the marrow fails to make enough blood cells. A bone marrow transplant may also temporarily reduce neutrophil counts until recovery occurs.
- Autoimmune Conditions: In some cases, the immune system mistakenly attacks neutrophils. Conditions such as lupus and rheumatoid arthritis can cause this type of neutropenia.
| Cause/Condition | How It Leads to Low Neutrophils |
|---|---|
| Leukemia/Lymphoma | Cancer cells overpopulate the bone marrow, pushing out healthy cells. |
| Chemotherapy | Damages bone marrow during treatment. |
| Radiation Therapy | Decreases bone marrow activity in the affected regions. |
| Aplastic Anemia | Marrow fails to produce blood cells. |
| HIV/AIDS | Weakens immune system and marrow. |
| Autoimmune Diseases | Immune system destroys neutrophils. |
Neutropenia can appear in different forms, from mild to severe, depending on the cause.
Other Non-Disease Causes
Not all cases of low neutrophils come from cancer or other diseases. Certain outside factors and lifestyle conditions can also lower counts for a short or long period.
- Medications are one of the most common non-disease causes. Some antibiotics can reduce neutrophil levels as a side effect. Other drugs, such as those used for autoimmune conditions, may also suppress bone marrow activity.
- Infections can temporarily lower neutrophils even after the illness has cleared. Viruses, including COVID-19, often cause short-term drops. Bacteria and fungi may also trigger changes in white blood cell production.
- Nutrient deficiencies play a role as well. Low levels of folate, vitamin B12, or copper can interfere with the body’s ability to make healthy neutrophils. Correcting these deficiencies usually helps restore normal counts.
- Medical treatments not tied to cancer, such as certain vaccines, can sometimes cause a brief dip in neutrophils. This effect is usually mild and does not last long.
The table below highlights common non-disease factors:
| Factor | Example or Detail | Effect on Neutrophils |
|---|---|---|
| Medications | Antibiotics, immune-suppressants | Lower production |
| Infections | Viruses (COVID-19), bacteria, fungi | Temporary decrease |
| Nutrient issues | Folate, vitamin B12, copper | Impaired formation |
| Vaccines | Routine immunizations | Short-term reduction |
People can sometimes have low neutrophils without a higher infection risk. This is called benign neutropenia and may not need treatment.
How It Causes the Symptom
The bone marrow, the soft tissue inside bones, produces most blood cells, including neutrophils. When cancer affects the bone marrow directly, it crowds out normal cells and reduces the number of neutrophils released into the bloodstream.
Cancers such as leukemia, lymphoma, and multiple myeloma start in the bone marrow itself. These cancers disrupt normal blood cell production by replacing healthy cells with cancer cells. This lowers neutrophil counts and weakens the immune system.
Other cancers may not begin in the bone marrow but still cause neutropenia. Tumors can spread into the marrow or trigger an enlarged spleen, which may trap and destroy neutrophils. Both processes reduce the number of circulating white blood cells.
Cancer treatments also play a major role. Chemotherapy and radiation therapy target fast-growing cells, including cancer cells, but they also damage bone marrow cells. This side effect often leads to a temporary drop in neutrophil levels. Key mechanisms include:
- Bone marrow infiltration by cancer cells.
- Suppression of marrow activity by chemotherapy or radiation.
- Immune system dysfunction caused by cancer or its treatment.
- Spleen enlargement that removes neutrophils from circulation.
Fewer neutrophils make it harder for the body to fight infections. This increases vulnerability to bacteria, fungi, and other microbes that a healthy immune system would usually control.
Possible Complications
Low neutrophil counts make the body less able to fight infections. Even minor illnesses can become more serious when neutrophils are very low, a condition called severe neutropenia.
Common warning signs include fever, chills, and cough. These may signal that the body is struggling to control an infection. Doctors often treat these symptoms quickly to prevent further problems.
Digestive issues such as diarrhea and vomiting may also occur. These can result from infections, medications, or the cancer itself. Loss of fluids from these symptoms can increase weakness and delay recovery. The table below highlights possible complications linked to low neutrophils:
| Complication | Possible Sign or Symptom | Why It Matters |
|---|---|---|
| Infection | Fever, chills, cough | Body cannot fight bacteria or viruses |
| Gastrointestinal issues | Diarrhea, vomiting | Risk of dehydration and malnutrition |
| Severe neutropenia | Very low neutrophil count | High risk of life-threatening infection |
Infections may spread quickly in people with neutropenia. Because the immune system is weakened, even everyday bacteria can cause complications.
When to Seek Medical Attention
People with low neutrophil counts face a higher risk of infection. Even minor infections can become serious quickly, so it is important to know when to get medical help. Seek medical care right away if any of these occur:
- Fever of 100.4°F (38°C) or higher.
- Chills, shaking, or sweats.
- New or worsening cough, sore throat, or shortness of breath.
- Burning sensation when urinating.
- Redness, swelling, or pain around a wound.
A fever with low neutrophil counts, called febrile neutropenia, needs urgent treatment because the body may not fight infection well. Other warning signs include mouth ulcers, unusual fatigue, or frequent infections.
These can signal very low neutrophil levels and a struggling immune system. When neutrophil counts drop below 500 cells per microliter of blood, the risk of severe infection rises sharply. At this level, even bacteria that normally live in the mouth, skin, or gut can cause illness.
People receiving chemotherapy, radiation, or living with cancers that affect the bone marrow should stay alert to these signs. Quick medical attention can prevent complications and lower the risks linked to neutropenia.
