White blood cells (WBCs) fight infections from bacteria, viruses, fungi, and other germs. One important type of WBC is the neutrophil. These cells are made in the bone marrow and travel in the blood throughout the body. They sense infections, gather at sites of infection, and destroy the germs.
When the body has too few neutrophils, the condition is called neutropenia. This makes it harder for the body to fight off infection, and a person is more likely to get sick. In general, an adult who has fewer than 1,000 neutrophils in a microliter of blood has neutropenia.
If the neutrophil count is very low, fewer than 500 neutrophils in a microliter of blood, it is called severe neutropenia. When the neutrophil count gets this low, even the bacteria normally living in a person's mouth, skin, and gut can cause serious infections.
Neutropenia and cancer; Absolute neutrophil count and cancer; ANC and cancer
A person with cancer can develop a low WBC count from the cancer or from treatment for the cancer. Cancer may be in the bone marrow, causing fewer neutrophils to be made. The WBC count can also go down when cancer is treated with chemotherapy drugs, which slow bone marrow production of healthy WBCs.
When your blood is tested, ask for your WBC count and specifically, your neutrophil count. If your counts are low, do what you can to prevent infections. Know the signs of infection and what to do if you have them.
Prevent infections by taking the following measures:
If you have any of the following symptoms, contact your health care provider:
American Cancer Society website. Why people with cancer are more likely to get infections. www.cancer.org/cancer/managing-cancer/side-effects/low-blood-counts/infections/why-people-with-cancer-are-at-risk.html. Updated March 13, 2020. Accessed May 8, 2023.
Centers for Disease Control and Prevention website. Preventing infections in cancer patients. www.cdc.gov/cancer/preventinfections/index.htm. Updated January 9, 2023. Accessed May 8, 2023.
Freifeld AG, Kaul DR. Infection in the patient with cancer. In: Niederhuber JE, Armitage JO, Kastan MB, Doroshow JH, Tepper JE, eds. Abeloff's Clinical Oncology. 6th ed. Philadelphia, PA: Elsevier; 2020:chap 34.