The question of whether steroids can cause brain cancer requires distinguishing between the two main types of steroids used in medicine and illicitly, and examining current scientific evidence. A direct, causal link between typical steroid use and the initiation of brain cancer is not supported by current epidemiological data. However, the topic is complex because certain steroids are used extensively in treating existing brain tumors, and both types can have significant neurological effects.
Differentiating Steroid Classes
The term “steroids” covers two fundamentally different classes of compounds with distinct functions. The first class is Anabolic-Androgenic Steroids (AAS), synthetic derivatives of the male hormone testosterone. AAS are known for their anabolic effects, promoting the growth of skeletal muscle and bone, and their androgenic effects, which relate to the development of male characteristics.
The second class is Corticosteroids, modeled after the natural hormone cortisol produced by the adrenal glands. These agents are powerful anti-inflammatory and immunosuppressive drugs used to treat conditions such as asthma, allergies, inflammatory bowel disease, and autoimmune disorders. While AAS are associated with building tissue, corticosteroids are catabolic, working by suppressing immune responses and breaking down tissue.
Reviewing the Direct Cancer Link
Current scientific understanding does not establish a direct causal link between the use of corticosteroids or anabolic steroids and the initiation of primary brain cancer, such as gliomas, in healthy individuals. Gliomas are the most common type of malignant brain tumor and are the primary concern regarding brain tumors.
Epidemiological studies have not identified a clear association between typical steroid exposure and an increased risk of developing these tumors. However, some research suggests that the body’s natural steroid hormones may influence glioma development, as these tumors sometimes express sex hormone receptors. This indicates that while external drugs may not cause cancer, hormonal pathways might play a role in tumor biology.
For anabolic-androgenic steroids, the primary cancer concern focuses on organs like the liver and prostate, where AAS abuse has been linked to an increased risk of certain tumors. Although AAS act on receptors distributed throughout the body, including the brain, the high-dose misuse of AAS has not been definitively tied to the development of brain cancer. Robust human data supporting a direct carcinogenic link for brain tumors is currently lacking.
Steroid Use and Existing Brain Tumors
Corticosteroids are a mainstay in the supportive care of patients who already have brain tumors. These medications are used to manage peritumoral edema, a complication involving swelling around the tumor site.
The tumor or its treatment can compromise the blood-brain barrier, allowing fluid to leak into the surrounding tissue. This fluid accumulation increases intracranial pressure, causing severe symptoms like headaches, vomiting, and neurological deficits. Corticosteroids, particularly Dexamethasone, reduce the permeability of tumor capillaries, rapidly decreasing this vasogenic edema.
The administration of corticosteroids provides temporary symptomatic relief and can improve neurological function in approximately 70% of patients with cerebral metastases. Neuro-oncologists prefer Dexamethasone due to its high potency and minimal mineralocorticoid activity, which reduces the risk of water retention. Despite managing symptoms immediately, corticosteroids may affect tumor biology and potentially diminish the effectiveness of some cancer treatments, such as immunotherapy, by suppressing the immune response.
Known Neurological Side Effects
Although the link to cancer initiation is weak, both classes of steroids have significant neurological side effects that directly impact the brain. For corticosteroids, which are widely prescribed, neuropsychiatric adverse effects have been documented, including mood changes, depression, anxiety, and mania. These effects arise because glucocorticoid receptors are widely expressed in the brain, and their long-term modulation can lead to functional and anatomical changes.
Prolonged use of prescribed corticosteroids can cause structural alterations in the brain, including changes in the volume of white and gray matter. White matter volume changes can slow down neural communication, contributing to cognitive issues and slower response times. The incidence of psychiatric symptoms is notable, with studies reporting depression rates as high as 40.5% and mania around 27.8% in users.
The misuse of Anabolic-Androgenic Steroids (AAS) is associated with severe neurological and psychiatric consequences. Chronic AAS exposure is linked to mood disturbances, including increased aggression (“roid rage”), anxiety, and depression. These effects result from AAS interacting with androgen receptors in brain regions responsible for emotion and cognition, such as the amygdala and hippocampus.
Neuroimaging research indicates that prolonged, high-dose AAS use can lead to structural changes, including a reduction in gray matter volume in areas like the cortex. This neurotoxicity can manifest as cognitive deficits, impaired impulse control, and accelerated brain aging in long-term users. Withdrawal from AAS can exacerbate these issues, leading to severe depression, fatigue, and suicidal ideation.