Does TRT Cause Prostate Cancer? The Evidence Says No

The Fear That Kept Men Suffering

For decades, testosterone replacement therapy and prostate cancer were linked in the medical imagination like smoking and lung cancer. The belief was so deeply held that men with low testosterone — men with fatigue, depression, sexual dysfunction, and metabolic disease — were denied treatment based on a fear that was never supported by quality evidence.

That era is ending. Here is what we actually know.

Where the Myth Came From

In 1941, Charles Huggins published research showing that castration (removing testosterone) caused prostate cancer to regress, and that testosterone administration caused it to grow. He won the Nobel Prize for this work, and his findings were extrapolated into a blanket assumption: if removing testosterone shrinks prostate cancer, then adding testosterone must cause it.

The problem: Huggins studied men who already had metastatic prostate cancer. His findings were about treating existing advanced cancer, not about whether testosterone causes cancer in healthy men. That distinction got lost for 70 years.

What Modern Evidence Actually Shows

The TRAVERSE Trial (2023)

This was the study the field needed. TRAVERSE was a randomized, placebo-controlled trial of over 5,000 men with hypogonadism, followed for an average of 33 months. The primary endpoint was cardiovascular safety, but prostate outcomes were a key secondary endpoint.

Results: No statistically significant increase in prostate cancer in men receiving testosterone versus placebo. The incidence was low and similar between groups.

The Saturation Model

Abraham Morgentaler proposed the saturation model, which fundamentally changed our understanding. The concept: prostate tissue has a finite number of androgen receptors. Once those receptors are saturated (which occurs at relatively low testosterone levels — around 250 ng/dL), additional testosterone does not further stimulate prostate growth.

This explains why:

• Castrate levels of testosterone (near zero) allow cancer regression
• Normal physiologic levels saturate receptors
• Supraphysiologic levels do not add additional stimulation beyond saturation

Think of it like watering a plant. A bone-dry plant grows when you water it. But once the soil is adequately moist, adding more water does not make it grow faster — it just runs off.

Meta-Analyses

Multiple systematic reviews have now confirmed:

• TRT does not increase prostate cancer incidence in hypogonadal men
• TRT does not increase PSA beyond the first 6 months (initial normalization)
• TRT does not worsen outcomes in men with treated, low-risk prostate cancer

A 2016 meta-analysis in European Urology pooling over 250,000 patient-years found no causal association between testosterone therapy and prostate cancer.

What About PSA?

PSA (prostate-specific antigen) often rises when men start TRT. This alarms patients and providers alike. But understanding why reduces the panic:

• Low testosterone causes the prostate to atrophy (shrink)
• When testosterone normalizes, the prostate returns to its healthy baseline size
• A healthy-sized prostate produces more PSA than an atrophied one
• This PSA rise is physiologic normalization, not pathology

The typical pattern: PSA rises 0.3-0.5 ng/mL in the first 3-6 months, then stabilizes. If PSA continues rising rapidly after 12 months, that warrants investigation — but it is not common.

When Is Caution Still Warranted?

Evidence has not given us blanket permission to ignore the prostate. These situations require careful consideration:

Active Prostate Cancer

Men with untreated, active prostate cancer should not start TRT. The saturation model tells us that existing cancer cells with unsaturated receptors could be stimulated. Androgen deprivation therapy remains appropriate for advanced prostate cancer.

Recently Treated Prostate Cancer

This area is evolving rapidly. Growing evidence suggests that men with treated low-risk prostate cancer (Gleason 6, post-prostatectomy with undetectable PSA) can safely receive TRT. Multiple observational studies show no increased recurrence. However, this should be managed by a provider experienced in both urology and endocrinology.

High-Risk Features

Men with very high PSA, abnormal digital rectal exam, strong family history of prostate cancer, or BRCA2 mutations deserve more cautious surveillance while on TRT. This does not mean TRT is contraindicated — it means monitoring should be more frequent.

Appropriate Monitoring on TRT

Every man on testosterone therapy should have:

• Baseline PSA before starting treatment
• PSA at 3-6 months to establish the new baseline after normalization
• Annual PSA thereafter
• Digital rectal exam per standard screening guidelines
• Investigation if PSA rises more than 1.4 ng/mL from post-treatment baseline or exceeds 4.0 ng/mL

This is good preventive medicine regardless of TRT status. Every man over 50 should be having these conversations with their provider.

The Real Cost of the Myth

While we debated whether testosterone causes prostate cancer, millions of men suffered with:

• Depression attributed to aging
• Fatigue blamed on lifestyle
• Sexual dysfunction treated with pills instead of hormone correction
• Metabolic syndrome left unaddressed
• Osteoporosis diagnosed only after fractures

Low testosterone is not a cosmetic concern. It is a medical condition with serious downstream consequences. The myth that treating it causes cancer kept men — and their providers — from addressing it.

The Bottom Line

The weight of modern evidence is clear: testosterone replacement therapy in hypogonadal men does not cause prostate cancer. It does require appropriate monitoring, like any hormone therapy. And men with active prostate cancer need specialized evaluation before considering testosterone.

If you have been told you cannot have TRT because of prostate cancer risk — or if you have been afraid to ask about it — the science has evolved. Bring your questions to a provider who keeps up with the evidence.

At Coral, we prescribe TRT with appropriate monitoring and evidence-based protocols. [Start your visit](/start) and let us evaluate whether testosterone therapy is right for you.

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