Observational study finds supplemental testosterone linked to 38% lower death risk in glioblastoma — Evidence Review
Published in Nature, by researchers from Cleveland Clinic, NIH's National Cancer Institute
Researched by
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Table of Contents
Researchers from Cleveland Clinic found that testosterone supplementation was associated with a significantly lower risk of death in men with glioblastoma, suggesting the hormone may help limit tumor growth. Most related studies broadly support a protective or regulatory role for testosterone in brain cancer, though some findings are mixed regarding whether higher or lower levels are beneficial (1, 3, 4, 5, 6, 7). For more details, see the original publication in Nature.
- Several animal and human studies indicate testosterone may act as a tumor suppressor in glioblastoma, potentially through immune system regulation and modulation of brain barriers, consistent with the new findings (3).
- Some research reports that androgen deficiency is linked to better prognosis in glioblastoma, in apparent contrast to the current study, highlighting the complexity of hormone effects in the brain cancer context (1).
- Broader research on testosterone and mortality suggests higher testosterone is often associated with reduced mortality from various causes, including cancer, but not all studies find a direct link in brain tumors specifically (4, 5, 6, 7).
Study Overview and Key Findings
Glioblastoma is a highly aggressive brain tumor with limited effective treatments and a higher incidence in men. The reasons for this sex difference have long been unclear, with androgens such as testosterone previously suspected to contribute to increased risk. This new NIH-funded study from Cleveland Clinic challenges that assumption by suggesting testosterone may instead help restrain tumor growth, with loss of androgen signaling leading to a more immunosuppressive brain environment and poorer outcomes. The study combined preclinical mouse models with analyses of survival data in over 1,300 men with glioblastoma, providing a multi-layered approach to investigating how testosterone impacts disease progression.
| Property | Value |
|---|---|
| Study Year | 2026 |
| Organization | Cleveland Clinic, NIH's National Cancer Institute |
| Journal Name | Nature |
| Authors | Juyeun Lee, Yoon-Mi Chung, Daniel J. Silver, Yue Hao, Dylan Scott Lykke Harwood, Alyssa Ealy, Amanda M. Serapiglia, Lee Curtin, Julia R. Benedetti, Christine Ann Pittman Ballard, Kamya Lapsley, Andrea Alvarez-Vazquez, Jessica Goldberg, Cathy Li, Sehaj Kaur, Rian Neal, Sabrina Z. Wang, Kristen E. Kay, Josephine Volovetz, Ellen S. Hong, R’ay Fodor, Jakub Jarmula, Michael Nicosia, Joshua B. Rubin, Kristin R. Swanson, Quinn T. Ostrom, Nikhil Panicker, Bjarne Winther Kristensen, Michael Berens, Nima Sharifi, Justin D. Lathia |
| Population | Men with glioblastoma |
| Sample Size | n=1,300 |
| Methods | Observational Study |
| Outcome | Survival outcomes and tumor growth |
| Results | Supplemental testosterone linked to 38% lower death risk. |
Literature Review: Related Studies
To place these findings in context, we searched the Consensus paper database (over 200 million research papers) using several targeted queries to identify relevant literature. The following search queries were used:
- testosterone brain cancer survival rates
- testosterone effects on cancer mortality
- hormonal therapy brain tumor outcomes
Below, we summarize key themes and findings from the literature:
| Topic | Key Findings |
|---|---|
| How does testosterone influence glioblastoma prognosis and survival? | - Some studies indicate testosterone acts as a tumor suppressor in glioblastoma, improving survival by regulating immune responses (3). - Other research finds androgen deficiency may be linked to better prognosis in glioblastoma, suggesting complex effects (1). |
| What is the relationship between testosterone levels and overall mortality or cancer mortality in men? | - Higher endogenous testosterone levels are associated with reduced mortality from all causes, cardiovascular disease, and cancer in men (4, 5, 6, 8). - Not all studies find a direct association between testosterone levels and cancer mortality, and some report no significant link in large population cohorts (7). |
| How do sex hormones and hormonal therapies affect brain tumor risk and progression? | - Female sex hormones may be protective against glioma, while hormone replacement therapy and oral contraceptive use are associated with reduced glioma risk (9, 12). - Cross-sex hormone therapy can increase risk of certain benign brain tumors in transgender individuals, with complex effects depending on hormone type (10). |
| Does hormone therapy impact survival in patients with brain tumors or brain metastases? | - Endocrine therapy after diagnosis of brain metastases in breast cancer is associated with improved survival (11). - Long-term testosterone replacement in men is linked to reduced mortality and cardiovascular events, while short-term use may increase risk (6, 5). |
How does testosterone influence glioblastoma prognosis and survival?
The relationship between testosterone and glioblastoma prognosis is complex and context-dependent. The new Cleveland Clinic study suggests that testosterone supplementation may protect against glioblastoma progression, aligning with animal research indicating that testosterone can suppress tumor growth via effects on immune regulation within the brain (3). However, another study found that androgen deficiency—defined by lower circulating testosterone—was associated with better progression-free survival in glioblastoma patients (1), highlighting the nuanced and possibly opposing effects depending on the disease context, patient population, or local hormone environment.
- Testosterone appears to support anti-tumor immunity in animal models, potentially by modulating T cell responses and glucocorticoids (3).
- Androgen deprivation or deficiency may, in some cases, coincide with improved outcomes in glioblastoma, suggesting a context-specific effect (1).
- The new study's finding that supplemental testosterone is linked to lower mortality supports the possibility of a protective immune-regulatory role for testosterone in certain settings (3).
- Overall, the evidence points to a need for further mechanistic studies to clarify testosterone's role in glioblastoma progression (1, 3).
What is the relationship between testosterone levels and overall mortality or cancer mortality in men?
Multiple large observational studies have reported that higher endogenous testosterone levels are associated with decreased risk of death from all causes, including cardiovascular disease and cancer (4, 5, 6, 8). However, some studies do not find a direct relationship between testosterone and cancer mortality specifically, with factors such as age, co-morbidities, and hormone regulation pathways (e.g., LH/T ratio) potentially modifying this association (7).
- Higher testosterone is often linked to lower mortality rates, including from cancer, in general male populations (4, 5, 6, 8).
- Testosterone therapy in men with low testosterone has been associated with reduced mortality, but findings are observational and require confirmation from randomized trials (5, 6).
- Some studies find no significant association between testosterone and cancer mortality, suggesting possible confounding or population-specific effects (7).
- Duration of testosterone therapy may influence risk, with long-term therapy associated with benefit, but short-term therapy potentially increasing risk (6).
How do sex hormones and hormonal therapies affect brain tumor risk and progression?
Sex hormones, both endogenous and exogenous, have diverse effects on brain tumor risk and progression. In epidemiological studies, female sex hormones such as estrogens appear to be protective against gliomas, potentially explaining the lower incidence in women (9, 12). Hormone replacement therapy and oral contraceptives are associated with reduced glioma risk, but may increase risk for other tumors like meningioma. In transgender individuals, cross-sex hormone therapy (especially with certain anti-androgens or estrogens) is associated with increased risk for specific benign brain tumors (10).
- Estrogens are thought to have neuroprotective effects and may lower glioma risk (9, 12).
- Cross-sex hormone therapy can increase the incidence of certain benign brain tumors, such as meningioma and prolactinoma, depending on the hormonal regimen (10).
- Later menarche and menopause are associated with increased glioma risk, supporting a protective role for female hormones (9).
- The complexity of hormonal effects highlights the need for individualized approaches in hormone-related therapies for brain tumors (9, 10, 12).
Does hormone therapy impact survival in patients with brain tumors or brain metastases?
Hormonal therapies appear to influence survival outcomes in patients with certain brain tumors or metastases. Endocrine therapy in breast cancer patients with brain metastases has been associated with prolonged survival (11). In men, testosterone replacement therapy is linked to reduced mortality and cardiovascular events, though observational data suggest risks may depend on therapy duration (5, 6). These findings, while not specific to glioblastoma, indicate that hormone-based interventions can have meaningful impacts on survival in neuro-oncology settings.
- Endocrine therapy after brain metastasis in breast cancer is associated with improved overall survival (11).
- Testosterone replacement in men with low testosterone is linked to decreased mortality, but causality is not yet established (5, 6).
- Short-term hormone therapy may increase risks, emphasizing the importance of therapy duration and patient selection (6).
- Further clinical trials are needed to determine the efficacy and safety of hormonal therapies in primary brain tumors (5, 6, 11).
Future Research Questions
While the new study offers important insights into the role of testosterone in glioblastoma, many questions remain. Further research is needed to clarify the mechanisms involved, understand the differing effects seen in previous studies, and evaluate the safety and efficacy of hormonal interventions in brain tumor patients.
| Research Question | Relevance |
|---|---|
| Does testosterone supplementation improve survival in men with glioblastoma? | Randomized trials are needed to determine if the observed association between supplemental testosterone and reduced mortality is causal and to assess safety and efficacy in this population (3, 5, 6). |
| How do androgens modulate immune responses in the glioblastoma microenvironment? | Understanding the immunomodulatory role of androgens could reveal new therapeutic targets and clarify why testosterone appears protective in some studies but not others (3, 1). |
| Why do some studies find androgen deficiency beneficial while others find testosterone protective? | Reconciling these contradictory findings is essential to guide clinical recommendations and may point to additional factors (such as tumor genetics, patient age, or comorbidities) that influence hormone effects (1, 3, 4, 7). |
| What is the effect of testosterone replacement therapy duration on brain tumor outcomes? | Existing evidence suggests therapy duration may significantly impact benefit or risk, but this has not been specifically studied in glioblastoma (6). |
| How do sex hormones interact with other molecular pathways in glioblastoma progression? | Elucidating the interplay between hormones and molecular drivers of glioblastoma could help identify patient subgroups most likely to benefit from hormonal interventions and improve personalized therapy approaches (12, 9). |