Peter Attia MD310 - The relationship between testosterone and prostate cancer, TRT, and more
CHAPTERS
- 0:00 – 2:35
Cold Open and Setup for the TRAVERSE Discussion
The episode opens with a clip of Ted Schaeffer saying he would keep a patient on TRT if low-grade prostate cancer is found. Peter Attia then introduces the short, single-topic format and the TRAVERSE trial, which found that exogenous testosterone did not raise ASCVD risk.
- •Cold open previews Schaeffer's view on continuing TRT after a low-grade cancer diagnosis
- •This is a shorter episode focused on testosterone and prostate cancer
- •TRAVERSE asked whether exogenous testosterone raises ASCVD risk in men and found that it did not
- •The open question is what the trial showed about prostate cancer
- 2:35 – 6:30
What TRAVERSE Showed About Prostate Cancer
Schaeffer describes the trial population: hypogonadal men in their sixties with low PSAs, a small testosterone bump, and a high dropout rate. No more prostate cancers were diagnosed on testosterone than on placebo, and the total number was very low.
- •Participants were hypogonadal and low-risk, with a mean PSA around 0.9
- •Testosterone rose only about 140 ng/mL, and dropout at five years was above 60%
- •About 23 prostate cancers were detected, with no excess in the testosterone arm
- •Men diagnosed with cancer had higher baseline PSAs and bigger PSA shifts
- •PSA can be used in much the same way in men on exogenous testosterone
- 6:30 – 9:52
Was TRAVERSE Too Small or Short? Benign vs. Cancer Cell Sensitivity
Attia notes that the incidence curves diverge slightly and asks whether the trial was too short or too small to detect a difference. Schaeffer says he doesn't expect moving men from hypogonadal to eugonadal to drive cancer. He explains that benign prostate cells have higher androgen receptor density and are more sensitive to testosterone, which fits the worsening BPH symptoms seen in studies.
- •Attia raises the possibility of a longer or larger study showing a difference
- •Schaeffer doesn't think restoring eugonadal levels will induce or propagate prostate cancer
- •Benign prostate cells have denser androgen receptors than cancer cells
- •Testosterone supplementation in eugonadal men more often worsens BPH or urinary symptoms
- 9:52 – 12:57
The Androgen Receptor Saturation Theory
Schaeffer explains that once the androgen receptor in an organ is fully engaged, extra testosterone or DHT adds little. He says saturation thresholds differ by organ, with prostate and hair follicles saturating at low serum levels and muscle needing much higher ones.
- •The receptor moves from cytoplasm to nucleus and drives androgen-dependent genes
- •Prostate saturation is modeled at roughly 200-250 ng/mL serum
- •Muscle probably needs much higher levels for anabolic effects
- •Hair follicles resemble the prostate because of high 5-alpha reductase
- •Saturation is common among receptor superfamilies, so raising serum T has limited impact on prostate cancer growth
- 12:57 – 16:17
Checking the Numbers: DHT Amplification and Real-World Effects
Attia restates the saturation figures and notes that most men are already above the prostate saturation level. Schaeffer explains that 5-alpha reductase converts testosterone to DHT, which is about ten times more potent. He cites PSA as an androgen-responsive gene that does not jump when men go from 300 to 800.
- •Attia says roughly 90% of men are already at or above the prostate saturation level
- •DHT is about 10 times more potent than testosterone
- •Raising testosterone from 300 to 800 usually causes little PSA change and only subtle urinary effects
- •The same raise can produce a clear benefit in muscle mass
- •PSA is an androgen-responsive gene used to estimate saturation
- 16:17 – 20:22
Low Testosterone, High-Grade Cancer, and Androgen Receptor Activity
Attia revisits the New England Journal of Medicine paper linking lower testosterone to higher-grade prostate cancer. Schaeffer describes his lab's androgen receptor activity signature, which found that more aggressive tumors show less canonical AR output and rely on other growth mechanisms.
- •The earlier paper linked lower PSA and testosterone with higher-grade tumors
- •Schaeffer's team built a signature measuring androgen receptor output within tumors
- •More aggressive tumors showed lower AR activity
- •Aggressive tumors depend on other growth pathways and have different vulnerabilities to therapy
- 20:22 – 26:29
The ARA Signature and the Decipher Assay
Schaeffer explains that the ARA score is an mRNA expression assay on biopsy or surgical tissue, built from nine canonical androgen-responsive genes. He describes a garden-weeds analogy for low and high AR tumors and says the CLIA-approved Decipher test and its GRID data make this available through a physician.
- •The assay measures gene expression, not mutations, and can be run on biopsy, resected, or metastatic tissue
- •Larger gene sets of 250 or 600 genes tell the same story
- •High-AR tumors are like big weeds with tiny roots, while low-AR tumors show MYC and other aggressive signaling
- •Decipher gives a single aggressiveness score, and the GRID adds AR activity and basal/luminal features
- 26:29 – 31:13
Using Molecular Scores in Treatment Decisions and Radiation Trials
Using a Gleason 3+3 example, Schaeffer says molecular scores matter less for low-grade tumors, where only about 7% are aggressive by Decipher. For higher-grade tumors, ongoing NRG radiation trials are testing whether low-ARA tumors need intensified androgen suppression with newer agents.
- •Gleason 3+3 tumors are rarely molecularly aggressive
- •Standard surveillance can also identify outliers
- •Low-ARA tumors may be more sensitive to doublet therapy, according to Phase 3 trial analyses
- •NRG trials stratifying by genomics should report within about two years
- 31:13 – 33:12
Surgery vs. Radiation and Androgen Deprivation in Low-ARA Tumors
Attia asks whether a low-ARA Gleason 3+4 tumor points toward surgery rather than radiation with androgen deprivation. Schaeffer agrees that avoiding systemic hormonal therapy is a major win, and explains that androgen deprivation increases radiation sensitivity through DNA damage.
- •Surgery leaves nothing to modify with ADT, so it can spare patients total androgen suppression
- •Avoiding the morbidity of ADT is a major benefit
- •Radiation does not increase androgen sensitivity
- •Androgen suppression induces DNA damage and works synergistically with radiation
- 33:12 – 39:05
TRT in Patients With Low-Grade Prostate Cancer
Attia asks what gives Schaeffer pause about TRT, and Schaeffer says he can't think of a scenario to advise against it in a symptomatic, cancer-free man. He would keep a man on TRT after a low-grade diagnosis, arguing that testosterone is a differentiating factor and that a man at 800 on TRT is like any man naturally at 800.
- •Low T carries cardiovascular, bone, muscle and cognitive risks beyond prostate cancer
- •Schaeffer would continue TRT in a man diagnosed with low-grade cancer on surveillance
- •No evidence shows exogenous T accelerates prostate cancer, and about 30% of men naturally have T of 800 or higher
- •Testosterone differentiates prostate cells, and tumors arising in low-T settings are less androgen-dependent and more worrisome
- 39:05 – 43:47
Higher-Grade Cancer: Surgery, Radiation, and Testosterone Recovery
For cancers that need treatment, such as Gleason 4+3 or higher, Schaeffer says radiation requires aggressive androgen suppression that drops T to zero. He may advise surgery so testosterone can be maintained, noting that radiation oncologists hesitate to restart T and that only 50 to 60% of men recover normal T after two years of ADT.
- •Radiation with ADT takes testosterone to zero, which is highly symptomatic
- •With surgery and favorable pathology, TRT can continue, perhaps at about 400
- •Radiation leaves residual benign tissue, so restarting T risks a false-positive recurrence signal
- •Only 50 to 60% of men recover normal T after two years of hormonal suppression
- •Three NRG trials are testing intensification and de-intensification of ADT
- 43:47 – 48:20
Adjuvant Therapy, PSA as a Biomarker, and Closing
Attia compares adjuvant anti-estrogen therapy in breast cancer with prostate cancer. Schaeffer says PSA is an exquisitely sensitive biomarker that detects recurrence early, so prostate care can rely on early salvage therapy rather than universal adjuvant suppression. They discuss how liquid biopsies could help breast cancer and then close the episode.
- •Women with ER-positive breast cancer typically get adjuvant anti-estrogen therapy, with serious side effects
- •Prostate cancer has PSA, which can detect recurrence of as few as 100 to 200 cells
- •Early salvage therapy lets clinicians act like a sniper rather than use a bazooka
- •Cell-free DNA tests may let breast cancer follow a similar targeted approach
- •Attia says this mini-drive format was an experiment
