Immunocompromised — Weakened Immunity in Cancer Care

An immunocompromised state, also referred to as immunosuppression or immunodeficiency, occurs when one or more components of the immune system are depleted, absent, or malfunctioning. In an oncology setting, this most commonly manifests as secondary or acquired immunosuppression. The body lacks sufficient quantities of functional white blood cells—such as neutrophils, lymphocytes, or monocytes—or cannot produce adequate immunoglobulins.

Without these vital defensive mechanisms, the body struggles to neutralise common environmental pathogens. Even micro-organisms that normally live harmlessly on the skin or within the digestive tract, known as opportunistic pathogens, can cross compromised physical barriers and cause life-threatening systemic infections, severe sepsis, or organ failure.

Knowing you are immunocompromised shifts the priorities of daily care. A mild fever or minor cough that might normally be dismissed requires urgent clinical assessment when immunity is compromised. Recognizing this state empowers you and your caregivers to practice infection control, adjust food safety habits, maintain up-to-date non-live immunisations, and seek rapid medical attention at the first sign of illness before complications escalate.

A standard laboratory test called a complete blood count (CBC) or full blood count (FBC) with differential is used to evaluate immune status. Oncologists monitor the absolute neutrophil count (ANC) to detect neutropenia, absolute lymphocyte counts, and sometimes serum immunoglobulin levels to measure overall humoral immunity.

Immunosuppression is particularly pronounced in haematological malignancies, such as acute and chronic leukaemias, multiple myeloma, and non-Hodgkin or Hodgkin lymphomas, which directly disrupt bone marrow function. It also affects patients with solid tumours undergoing intensive systemic chemotherapy or radiation.

When patients are severely immunocompromised, cancer therapies may be paused or dose-reduced to allow bone marrow recovery. Clinical teams often prescribe prophylactic antibiotics, antivirals, or antifungals, alongside granulocyte colony-stimulating factors (G-CSF) to stimulate white blood cell production. Immediate emergency hospitalisation is required if a fever develops during periods of neutropenia.