Low Testosterone and the Risk of Prostate Cancer Progression
Low Testosterone May Raise Risk of 'Extreme' Prostate Cancer Progression | MedPage Today
A Surprising Twist on an Old Story
A landmark study from MD Anderson Cancer Center turns decades of conventional wisdom on its head — finding that men with low testosterone may face greater risk of their prostate cancer becoming more aggressive while under watchful waiting.
- A new study of 924 men on active surveillance found that those with low testosterone (≤300 ng/dL) had a 61% higher risk of their cancer progressing to an aggressive Grade Group 3 or higher.
- This challenges the century-old belief that high testosterone "feeds" prostate cancer. New science suggests it's actually low testosterone that may allow early-stage disease to become more dangerous.
- Experts stress that this study does not mean men should rush to seek testosterone therapy. Results are preliminary and no clinical change is recommended yet — but the findings call for urgent prospective research.
- The study also did not find a significant link between low testosterone and moderate (Grade Group 2) progression, suggesting the effect is specific to higher-grade, more aggressive disease.
- Measuring baseline testosterone at the start of active surveillance may eventually become a standard tool to help identify which men need closer monitoring.
The Study That Changed the Conversation
For most of the past century, the prevailing wisdom was simple and intuitive: testosterone feeds prostate cancer the way gasoline feeds a fire. This belief traced back to the pioneering work of Dr. Charles Huggins in the 1940s, who demonstrated that removing the source of testosterone — through castration — could shrink prostate tumors. His discovery eventually earned him the Nobel Prize and gave birth to androgen deprivation therapy (ADT), which remains a cornerstone of treatment for advanced prostate cancer today.
"Understanding how hormonal factors influence prostate cancer biology may help us refine surveillance strategies." — Dr. Justin R. Gregg, MD Anderson Cancer Center
But a major new study published in February 2026 in The Journal of Urology presents a striking counterintuitive finding: for men with early-stage prostate cancer who are being monitored under active surveillance, having lower testosterone may actually be the more dangerous condition.
Researchers at The University of Texas MD Anderson Cancer Center found that prostate cancer patients with low testosterone levels may have a higher risk of cancer progressing to a more aggressive form while under active surveillance. The findings suggest that baseline testosterone may serve as a useful clinical marker to better stratify risk and tailor monitoring strategies for patients choosing active surveillance.
What the Study Did — and What It Found
Researchers conducted a retrospective cohort study of 924 men enrolled in an active surveillance program between 2001 and 2024, with a median follow-up of 46.1 months among those who did not progress. Serum testosterone levels were categorized as low if they met a threshold of ≤300 ng/dL, based on established clinical guidelines. The primary outcomes studied were biopsy progression to Grade Group 2 (moderate progression) or Grade Group 3 or higher (what the researchers termed "extreme" progression).
The study group was representative of typical active surveillance patients: the mean age was 63.6 years, the average PSA density was 0.13 ng/mL², and the average baseline testosterone was 394 ng/dL — but notably, 29.4% of the 924 men had a testosterone level at or below 300 ng/dL. That is nearly one in three men on surveillance who might be classified as having low testosterone by current medical guidelines.
The critical result: patients with low baseline testosterone levels (300 ng/dL or lower) had a significantly higher likelihood of their cancer progressing to Grade Group 3 or higher, with a hazard ratio of 1.61 (95% confidence interval 1.03–2.51, P = 0.04). In plain terms, men with low testosterone at the start of active surveillance had about a 61% higher relative risk that their cancer would escalate to an aggressive grade during follow-up.
The researchers also reported that low testosterone was not associated with risk of progression to Grade Group 2 disease or higher. The association was specific to the most dangerous type of escalation — a distinction that may carry important biological meaning.
| Grade Group | Gleason Score | What It Means |
|---|---|---|
| GG 1 | ≤6 | Low-risk; slow-growing; most men qualify for active surveillance |
| GG 2 | 3+4=7 | Favorable intermediate-risk; still often surveillance-eligible |
| GG 3 | 4+3=7 | Unfavorable intermediate-risk; more aggressive behavior expected |
| GG 4 | 8 | High-risk; treatment typically recommended |
| GG 5 | 9–10 | Very high-risk; most aggressive form |
Importantly, low testosterone levels were associated with an increase in the likelihood of disease progression even after accounting for other factors including age, PSA, body mass index (BMI), tumor density, and tumor size. This means the finding holds up even when the researchers tried to rule out competing explanations — strengthening confidence that testosterone itself (or its biological correlates) plays an independent role.
Why This Seems Backwards — and Why It Might Not Be
To understand why low testosterone might actually be bad news for prostate cancer patients, it helps to understand how the scientific thinking on this topic has evolved over the past two decades.
The old "androgen hypothesis" held that more testosterone meant more cancer fuel. But as researchers tested this hypothesis in clinical settings, the evidence grew contradictory. Men with higher testosterone didn't consistently have worse cancer. Men given testosterone therapy didn't reliably develop new prostate cancers. Something didn't add up.
"Nature has designed a system where low doses of hormones stimulate cancer cell proliferation and high doses cause differentiation and suppress growth." — Dr. Donald McDonnell, Duke Cancer Institute, Nature Communications (2024)
The answer began to emerge with the development of the "testosterone saturation model," proposed by Dr. Abraham Morgentaler and colleagues. This model suggests that prostate growth is exquisitely sensitive to variations in androgen concentrations at very low concentrations but becomes insensitive to changes in androgen concentrations at higher levels — consistent with the observation that androgens exert their prostatic effects primarily via binding to the androgen receptor, and that maximal androgen-androgen receptor binding is achieved at serum testosterone concentrations well below the physiologic range.
In other words, once testosterone rises above a certain threshold, adding more has little effect on prostate tissue. But below that threshold — in the low-testosterone zone — the prostate may become highly sensitive to even small hormonal fluctuations.
A landmark 2024 study from Duke University's Cancer Institute, published in Nature Communications, provided the most detailed molecular explanation yet. The researchers found that prostate cancer cells are hardwired with a system that allows them to proliferate when testosterone levels are very low. When androgen levels are low, the androgen receptor is encouraged to "go solo" in the cell — activating pathways that cause cancer cells to grow and spread. However, as androgens rise, the androgen receptors are forced to work in pairs, creating a form of the receptor that halts tumor growth.
This molecular "solo vs. pair" mechanism elegantly explains decades of clinical paradoxes — and lends strong biological plausibility to the MD Anderson finding that low testosterone could be associated with the most aggressive prostate cancer progression.
What Expert Commentators Are Saying
The Journal of Urology published an accompanying editorial from Dr. Jeffrey J. Tosoian of Vanderbilt University Medical Center and colleagues, who called the findings significant and noted that they "further challenge the historical paradigm, now suggesting that low serum testosterone may in fact increase the risk of meaningful progression during active surveillance." The editorial described low testosterone as a "potentially modifiable risk factor" — language that opens the door to future clinical intervention trials.
Lead study author Dr. Justin R. Gregg was careful to put the findings in perspective. He told MedPage Today: "It does raise the prospect that a low testosterone level may be associated with an increased risk of future progression. It's not to the point where you would recommend some kind of clinical change — for example, giving testosterone, or automatically checking testosterone levels, in someone who starts on surveillance. But I think it does call for the need for further study to really validate this and see if this is a consistent finding."
The Broader Landscape: Related Research You Should Know About
Low testosterone and mortality. A 2025 study published in Cancer Medicine extended the concern beyond progression risk alone. In a post-randomization analysis, patients in otherwise good health with low versus normal testosterone had a significantly higher prostate cancer-specific and all-cause mortality risk. This suggests the potential impact of testosterone deficiency may reach further than just biopsy grade changes.
Prior evidence linking low testosterone to worse pathology. A 2017 Italian study (Ferro et al.) found that low serum testosterone predicted cancer "upgrading" and "upstaging" at radical prostatectomy in men who met active surveillance criteria — an earlier signal consistent with the new MD Anderson findings. This work was cited in a major 2025 systematic review of testosterone therapy safety.
Is testosterone therapy safe for men on active surveillance? Multiple recent studies have addressed this directly. A 2024 population-based analysis published in European Urology Open Science examined men on active surveillance who received testosterone therapy versus those who did not. The study demonstrated that testosterone therapy does not appear to increase the risk of conversion to active treatment, or prostate cancer-specific or overall mortality in men with untreated prostate cancer on active surveillance — results that align with the saturation model concept.
A 2025 study from Baylor College of Medicine (Applewhite et al.), published in The Journal of Sexual Medicine, likewise examined the impact of testosterone replacement in hypogonadal men specifically on active surveillance. While the use of testosterone replacement therapy in men undergoing active surveillance for prostate cancer has been historically contraindicated, recent studies have contributed to a paradigm shift to this approach.
A comprehensive 2025 systematic review by Santucci et al. in BJU International reviewed 19 studies spanning active surveillance, post-prostatectomy, and post-radiotherapy patients. Progression rates on active surveillance ranged from 0% to 32% and did not differ significantly from non-exposed controls on retrospective comparison at follow-up as long as 70 months. The authors concluded that retrospective evidence supports cautious use of testosterone therapy in low-to-intermediate-risk disease on active surveillance.
A scoping review published in Nature / International Journal of Impotence Research (2025) analyzed 12 studies from 2005 through 2025. Across all studies reviewed, testosterone replacement therapy was not associated with increased risk of biochemical recurrence or cancer progression. Instead, it demonstrated consistent efficacy in restoring serum testosterone levels and alleviating symptoms of hypogonadism.
Institutional guidelines: a divide remains. There is currently a notable split among major professional organizations on this issue. The European Association of Urology still considers localized and metastatic prostate cancer an absolute contraindication for testosterone replacement therapy. The American Urological Association states there is no strong evidence linking testosterone replacement with increased risk of developing prostate cancer. A January 2026 British Society for Sexual Medicine consensus statement, published in World Journal of Men's Health, reviewed the evidence and similarly called for individualized decision-making in carefully selected patients — particularly those on active surveillance after thorough discussion with their physicians.
What This Means for You as a Patient
- Don't panic — but do ask questions. If you are on active surveillance, ask your urologist whether your testosterone level has been measured and what it was. This is not yet a standard part of active surveillance protocols, but it may become one.
- Low testosterone is common. Nearly 30% of the men in this study had testosterone at or below 300 ng/dL. If you are in this range, more frequent or intensive surveillance monitoring may be warranted — discuss this with your physician.
- Do not self-medicate. The evidence is not yet strong enough to recommend testosterone replacement therapy as a way to prevent cancer progression. This study is retrospective and needs prospective validation before clinical guidelines change.
- Understand the grade group system. The risk identified in this study was specifically for progression to Grade Group 3 or higher — the threshold that typically prompts a transition from surveillance to active treatment. Talk with your doctor about your current grade and what progression would mean for your care plan.
- Broader health context matters. Low testosterone is associated with multiple health concerns beyond prostate cancer, including cardiovascular risk, metabolic syndrome, and reduced quality of life. This is another reason to discuss your hormone levels with your physician as part of overall health management.
Important Limitations to Keep in Mind
The MD Anderson study is a significant contribution, but it carries important caveats that the authors themselves acknowledged. The study was retrospective — meaning it analyzed existing medical records rather than a prospective controlled trial. Patients were all treated at a single institution, which may limit how broadly the results apply. Additionally, the study was completed during an era in which MRI-based prostate cancer risk stratification was not routinely used, which may have led to imprecise initial grading. Today's active surveillance protocols, which typically include multi-parametric MRI (mpMRI), are more precise.
The study also did not assess whether testosterone levels changed over time during surveillance, nor did it evaluate whether treating low testosterone altered progression outcomes. Those critical questions will require prospective, randomized trials — the gold standard for clinical evidence.
Looking Ahead: What Research Is Needed
Both the study authors and their editorial commentators call for the same next step: prospective validation. This means designing a forward-looking clinical trial in which men starting active surveillance have their testosterone measured at baseline and are then followed carefully — comparing outcomes between those with low and normal testosterone, and potentially testing whether testosterone replacement in hypogonadal men reduces progression rates.
Such trials would ideally incorporate modern MRI-based staging, liquid biopsy markers, and genomic assays alongside testosterone measurement — providing a comprehensive picture of the hormonal, biological, and imaging factors that predict who needs earlier intervention.
For now, the MD Anderson study stands as a compelling hypothesis-generator. It raises profound questions about a hormonal relationship that medicine has studied for 80 years — and suggests the story is far more nuanced than "testosterone is the enemy." For the roughly 1 in 3 men on active surveillance who may have low testosterone, that nuance could eventually translate into more personalized, better-targeted care.
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