A fever, an elevated body temperature of 100.4°F (38°C) or higher, commonly signals an infection. However, it can also be a symptom of cancer. Though less frequent than infections, cancer-related fever often appears with other symptoms that warrant medical evaluation.
Cancers Commonly Associated with Fever
Certain cancers are commonly linked to fever, especially hematologic malignancies (blood, bone marrow, lymph nodes). These include lymphomas (Hodgkin and non-Hodgkin), where fever can be prominent. The fever may be low-grade, fluctuating, and without an apparent infectious cause. In lymphomas, fever often accompanies systemic symptoms like night sweats and unexplained weight loss.
Leukemias (acute and chronic) also commonly cause fever. This can result directly from cancer cells or from infections due to a weakened immune system. Abnormal white blood cells in leukemia may trigger inflammatory responses.
Kidney cancer (renal cell carcinoma or RCC) is another malignancy linked to fever. Fever in RCC often stems from paraneoplastic syndromes, where the tumor releases substances causing systemic effects unrelated to direct tumor spread. For some, fever can be an initial symptom.
Liver cancer (hepatocellular carcinoma) can also cause fever due to inflammation. Soft tissue sarcomas may also induce fever. Less commonly, other solid tumors like ovarian, pancreatic, stomach, colon, breast, and lung cancers can cause fever if they become necrotic, lead to obstructions, or metastasize extensively. Widespread inflammation from cancer spread, particularly to the liver or bones, can also result in fever.
How Cancer Leads to Fever
Fever in cancer develops through several physiological mechanisms. One way is the release of pyrogenic substances, particularly cytokines. Cancer cells or immune cells responding to the tumor produce these fever-inducing proteins (e.g., Interleukin-1, Interleukin-6, Tumor Necrosis Factor-alpha). These cytokines travel to the brain’s hypothalamus, the body’s thermostat, elevating core body temperature.
Tumor necrosis, the death of cancer cells, is another factor. As these cells die, they release inflammatory substances into tissues and the bloodstream. This cellular debris and inflammatory mediators can trigger a systemic inflammatory response, leading to fever.
The immune system also generates heat in response to cancer. Its attempt to fight cancer cells activates immune pathways, producing heat as a byproduct. Certain immune cells, like gamma-delta T cells, are thought to be involved.
A tumor can also cause fever indirectly by obstructing ducts or organs. These blockages create an environment for bacterial growth, leading to infections. For example, a tumor blocking a bile duct or urinary tract can result in an infection and fever. Here, the fever is from the infection, but the cancer is the underlying cause.
Recognizing Cancer-Related Fever
Distinguishing cancer-related fever from more common fevers involves observing its characteristics and accompanying symptoms. One notable feature is its unexplained origin, occurring without a clear infectious cause, such as a cold, flu, or other common illnesses.
The fever may be persistent or recurrent, lasting days to weeks or repeatedly returning. While temperature can vary, it is frequently low-grade, typically between 99.5°F (37.5°C) and 100.3°F (37.9°C).
Cancer-related fevers are often accompanied by other systemic symptoms, sometimes referred to as “B symptoms.” These include unexplained weight loss (defined as a loss of at least 10% of body weight over six months), drenching night sweats, and significant fatigue that does not improve with rest. A nocturnal pattern, where the fever is worse at night, can also be observed.
When to Consult a Healthcare Professional
Any persistent, recurrent, or unexplained fever warrants evaluation by a healthcare professional. Seek medical attention if the fever is accompanied by other concerning symptoms, such as unexplained weight loss, significant fatigue, drenching night sweats, new lumps or swellings, or persistent localized pain.
Fever can signal numerous health conditions, from common infections to serious diseases. Only a healthcare professional can accurately determine its cause through evaluation and diagnostic tests. Avoid self-diagnosing; consult a medical provider for any unexplained or concerning fever.