Low White Blood Cells in Ovarian Cancer: Meaning, Risks, and What to Do

Low white blood cells especially low neutrophils (called neutropenia) often happen during or after ovarian cancer treatments and mainly mean a higher risk of infection, not that your cancer is worsening. ^[1] When counts drop, your body has fewer infection‑fighting cells, so even minor germs can cause serious illness, which is why this side effect deserves attention and prompt action when red‑flag symptoms appear. ^{[2] [3]}

What “Low White Blood Cells” Means

• White blood cells (WBCs) defend against germs; neutrophils are a key subtype that quickly attack bacteria and fungi. ^[2]
• Neutropenia generally means neutrophils below about 1,000 per microliter, and it is considered severe below 500, which carries the highest infection risk. ^[3]
• In ovarian cancer care, several treatments including chemotherapy and some targeted therapies like PARP inhibitors can lower neutrophils, making infections more likely and sometimes causing treatment delays until counts recover. ^{[1] [4]}

Common Causes in Ovarian Cancer Care

• Chemotherapy damages fast‑growing cells, including healthy white blood cells in the bone marrow, which is why neutropenia is common 7–14 days after a chemo dose. ^{[5] [6]}
• Certain targeted therapies used in advanced or recurrent ovarian cancer (for example, niraparib) can also reduce neutrophils and increase infection risk. ^[4]
• Other factors (prior treatments, nutritional status, infections, or individual variability) may add to the risk, but treatment‑related marrow suppression is the most common cause. ^[7]

Why It Matters

• With too few neutrophils, infections can escalate quickly; even your mouth or gut’s normal bacteria can cause serious illness during severe neutropenia. ^[3]
• Infections during low counts can be dangerous and may require hospital care, and they can force your oncology team to delay or adjust your treatment plan. ^[1]

Red‑Flag Symptoms That Need Urgent Care

Seek immediate medical attention (often the emergency department) if you develop any of the following while your counts are low or you’re receiving treatment:

• Fever of 38.0°C (100.4°F) or higher, chills, or sweats. ^[8]
• Sore throat, new cough or shortness of breath, burning with urination, abdominal pain, or persistent diarrhea. ^[8]
• Feeling faint, very unwell, or any rapidly worsening symptom. ^[8]

Fever during neutropenia is an emergency because the body may not show typical infection signs, and prompt antibiotics can be lifesaving. ^[8]

How Your Team May Manage It

• Temporary treatment hold or dose adjustment until counts recover; this is common and done to keep you safe. ^[1]
• Growth factor injections (G‑CSF such as filgrastim or pegfilgrastim) to help the bone marrow make neutrophils faster, especially if you’ve had febrile neutropenia or prolonged low counts. ^{[9] [10]}
• More frequent blood count checks during high‑risk periods (often about a week after chemo when the “nadir,” or lowest count, is expected). ^[1]

Practical Prevention Tips You Can Use

• Practice strict hand hygiene and avoid close contact with people who are sick. ^[11]
• Ask your care team when your counts are likely to be lowest so you can be extra cautious during that window (commonly 7–14 days post‑chemo). ^[12]
• Cook meats thoroughly, wash fruits/vegetables well, and avoid raw seafood or undercooked eggs to reduce foodborne infections. ^[13]
• Keep skin and mouth healthy: gentle oral care, treat cuts promptly, and avoid activities that may cause injuries when counts are low. ^[13]
• Stay current on recommended vaccines per your oncology team’s guidance, and report new symptoms early rather than waiting. ^[11]

Should You Be Concerned?

It’s understandable to feel worried, but low white blood cells during ovarian cancer treatment are common and often manageable with monitoring, prevention strategies, and timely interventions. ^[1] The key is to recognize symptoms early, follow infection‑prevention steps, and keep close communication with your oncology team, who can adjust doses or use growth factors when needed to reduce risk. ^{[1] [9]}

Quick Reference: Neutropenia Levels and Actions

Term	Approximate neutrophil count (per microliter)	What it can mean	Typical actions
Mild neutropenia	1,000–1,500	Lowered defenses, often no symptoms	Monitor counts; reinforce hygiene
Moderate neutropenia	500–999	Higher risk of infection	Closer monitoring; consider precautions and adjustments
Severe neutropenia	<500	Highest risk; infections can become serious quickly	Urgent evaluation for fever; possible antibiotics; consider G‑CSF and treatment modifications [3] [1] [9]

Bottom Line

• Low white blood cells in ovarian cancer most often reflect treatment effects on the bone marrow and signal an increased infection risk rather than cancer progression. ^[1]
• Stay alert for fever or sudden illness and seek urgent care if they occur, because fast treatment matters. ^[8]
• Many people safely continue therapy with monitoring, preventive steps, and, when needed, growth factor support or dose adjustments. ^{[1] [9]}