Systemic Lupus Erythematosus, commonly known as lupus, is a chronic autoimmune disease. It occurs when the body’s immune system mistakenly attacks its own healthy tissues and organs, leading to widespread inflammation. This can affect various parts of the body, including the skin, joints, kidneys, brain, blood cells, and heart. For individuals living with lupus, or for their families, understanding the potential connection between this condition and cancer is a common and understandable concern.
The Link Between Lupus and Cancer
Lupus does not directly cause cancer in the same way an infection might; rather, individuals with lupus have a statistically increased risk of developing certain cancers when compared to the general population. This means that while the risk is elevated, it is not a certainty, and most people with lupus will not develop cancer. A comprehensive meta-analysis involving 247,575 lupus patients found a 62% increased risk of overall cancer. Another study from 2021 suggests that lupus patients face a 50% increased risk of dying from cancer compared to the general public.
Cancers Associated with Lupus
Several types of cancer show a statistically significant association with lupus:
Lymphomas, particularly non-Hodgkin lymphoma, are consistently linked, with some studies reporting a relative risk ranging from 4.39 to 44.4. This increased risk is thought to stem from the disease process itself, including B-cell overstimulation and immune system defects.
Leukemia, another blood cancer, also shows an increased association, with lupus patients having a reported 13 times higher risk compared to the general population.
Lung cancer is approximately 1.4 to 1.63 times more common. Smoking remains a significant risk factor for lung cancer in lupus patients, similar to the general population.
Cervical cancer has an elevated risk in women with lupus, potentially due to immune dysregulation affecting the body’s response to human papillomavirus (HPV). Women with lupus are at twice the risk of developing cervical dysplasia or invasive cervical cancer.
Other cancers with reported associations include cancers of the liver, kidney, thyroid, bladder, esophagus, and non-melanoma skin cancers.
Why Lupus Might Increase Cancer Risk
Several factors contribute to the elevated cancer risk in lupus patients. Chronic inflammation, a hallmark of lupus, plays a role as persistent inflammation can damage DNA and promote cellular changes that may lead to cancer. This environment can promote tumor growth.
Immune system dysregulation is another contributing factor. A dysfunctional immune system, characteristic of lupus, may be less effective at detecting and eliminating cancerous cells (impaired immune surveillance). This imbalance can lead to overproduction of cytokines, causing immune system overactivity, increased inflammation, and tissue injury.
Certain immunosuppressive medications used to treat lupus can also increase cancer risk by suppressing the immune system. For instance, long-term use of azathioprine can increase cancer risk, and cyclophosphamide has been linked to an elevated risk of bladder cancer and hematological malignancies. However, some research suggests that the risk of cancer is highest during the earlier stages of lupus, implying that immunosuppressive therapy is not the sole link.
What to Know About Screening and Risk
For individuals with lupus, regular medical check-ups are important for monitoring their health. It is also important to adhere to general cancer screening guidelines recommended for the general population based on age and sex, such as mammograms, colonoscopies, and Pap tests.
Women with lupus, especially those on immunosuppressive drugs, are at a higher risk for HPV-related cervical cancer and should undergo regular Pap testing.
Open communication with healthcare providers, including rheumatologists and primary care physicians, is important for discussing specific lupus symptoms, medications, family history of cancer, and any new or unusual symptoms.
Maintaining a healthy lifestyle, including avoiding smoking and maintaining a healthy weight, also contributes to overall disease prevention and can help reduce cancer risk.