Back to Studies

Study analysis · The Journal of urology · 2026

Low testosterone could be an early warning sign for aggressive prostate cancer in men who choose active surveillance – but only for the highest-risk progression.

Men with low testosterone (≤300 ng/dL) were 61% more likely to see their low-risk prostate cancer turn aggressive (Grade Group 3 or higher), but not more likely for moderate progression.

Reading level
Moderate certainty
Level 2b · Individual cohort studyAssociation, not causationNo causal claims

Overview

What the study found

The study in plain English — the bottom line, every takeaway we extracted, and what to do with them.

In simple terms

This study watched men with low-risk prostate cancer who decided to wait before treatment. The researchers checked their testosterone levels and later saw whose cancer got worse. They found that men with low testosterone were more likely to have their cancer become a bit more serious, but this doesn't prove that low testosterone caused it—it just shows a connection.

What’s the bottom line?

This study looked at men with low-risk prostate cancer who chose active surveillance (regular check-ups instead of immediate treatment). It found that men with low testosterone levels were more likely to see their cancer become more aggressive over time.

How strong is this study?

This study was done carefully: they looked at many men over many years and tried to account for things like age and weight that could affect the results. But because they didn't do an experiment—just watched what happened—we can't be sure that low testosterone is the real reason. Also, some important details like what other medicines the men took were missing, so we need more studies to confirm.

Reporting

75 / 100

  • COI disclosure+40/40
  • Data availability+35/35
  • Code availabilitycode not shared
Methodology

37 / 100

  • Randomizationnot randomized
  • Blindingnot blinded
  • Control groupno control group
  • Sample size (n=924)+19.8/20
  • Follow-up+10/10
Publication

100 / 100

Statistical

77 / 100

  • P-values+15/15
  • Effect size+20/20
  • Confidence intervals+15/15
  • Pre-registrationnot pre-registered

Each component is scored out of 100 and then capped by the study design — a case series cannot reach the ceiling a randomised trial can, however well it is reported.

Where it sits

RCT reviews

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Cohort Studies
Level 2b
67

67 / 100

Probability of being correct

Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.

This design cannot establish causation — the findings describe an association, not a cause. As a retrospective cohort study, it lacks randomization and a control group, so it can only show associations. Residual confounding from unmeasured factors (e.g., medication use, genetic factors) cannot be ruled out. Causal claims are not justified.

COI Unknown

Could not determine conflict of interest status

No conflict of interest or funding information is provided in the accessible text. All authors are affiliated with academic institutions.

The full text is not accessible; only the abstract and metadata were analyzed. No COI or funding statements are visible.

Key takeaways

  1. 01

    About 29 out of 100 men had low testosterone.

  2. 02

    Those with low testosterone were 61% more likely to develop a high-grade cancer (Grade Group 3 or higher) compared to men with normal levels.

  3. 03

    A 61% increase is significant for individual patients, but because the overall risk of progression is still relatively low, the absolute increase is moderate.

Surprising findings

  • Low testosterone linked to higher, not lower, risk of aggressive prostate cancer progression.Many people assume testosterone fuels prostate cancer, so low levels would be protective. This study suggests the opposite for extreme progression.
  • The effect appears only for Grade Group 3+ progression, not Grade Group 2.One might expect a consistent effect across all progression grades, but the association is specific to the most aggressive cases.

Practical takeaways

Men starting active surveillance for prostate cancer should consider having their testosterone levels checked (morning blood draw) to assess risk.

This is based on a single retrospective study; discuss with your urologist before changing surveillance protocol.

medium confidence

If testosterone is low (≤300 ng/dL), consider more frequent monitoring or earlier biopsy to catch progression.

The study lacked MRI-based risk stratification, so combining with MRI might improve accuracy.

medium confidence

Don't assume low testosterone is protective – this study suggests the opposite for aggressive disease.

The absolute risk of progression is still relatively low; the 61% increase represents a moderate absolute increase.

medium confidence

Why this study matters

The 61% risk jump

Among 924 men on active surveillance, those with low testosterone had a 61% higher risk of extreme progression to Grade Group 3 or higher (HR 1.61, p=0.04). That's a significant bump for a cancer often considered low-risk.

This gives doctors a new way to identify which patients need closer monitoring or earlier treatment.

Moderate progression unaffected

Low testosterone was not significantly linked to progression to Grade Group 2 (HR 1.25, p=0.13). So it's not about all progression – just the most dangerous kind.

Shows that the effect is specific to aggressive disease, not just any worsening.

Nearly 1 in 3 men affected

29.4% of men starting active surveillance had low testosterone (≤300 ng/dL). That's a large subgroup that could benefit from risk stratification.

Highlights a common, underappreciated risk factor in a growing patient population.

Study limitations matter

The study is retrospective, single-center, lacked MRI-based risk stratification, and testosterone wasn't always taken in the morning – all of which weaken confidence.

Viewers appreciate honest science – show them how to weigh evidence.

Want the whole report?

Detailed mode opens the full scientific breakdown — every score component, the methodology, conflicts of interest, the evidence analysis behind each claim, and the raw study data.