# Testosterone after cancer treatment in men

Source: https://onco.cc/technologies/testosterone-after-cancer-treatment/  
OnCo record `testosterone-after-cancer-treatment` (Technology). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Low testosterone is common after cancer treatment and is rarely looked for: it was present in 38.5 per cent of 491 men treated for testicular cancer, in about half of a separate cohort whether or not they had chemotherapy, and in a third of adults given cranial radiotherapy. Replacement is straightforward where it is indicated; men with a prostate cancer history are the uncertain group.

## Summary

Three routes lead to low testosterone after cancer. Direct damage to the testis from chemotherapy, radiotherapy or the removal of one or both testicles; damage to the pituitary from cranial radiotherapy; and androgen deprivation given deliberately for prostate cancer, which is a different situation because the low testosterone is the treatment.

The numbers are larger than most follow-up clinics assume. Among 491 survivors of testicular cancer at a median age of 38, 38.5 per cent had hypogonadism, defined as testosterone at or below 3.0 nanograms per millilitre or current replacement, and they were more likely to be taking cholesterol or blood pressure medication and to report erectile dysfunction and neuropathy. A separate cohort of 199 men found biochemical hypogonadism in 48 per cent overall, 51 per cent after surgery and chemotherapy and 45 per cent after surgery alone, so chemotherapy is not the whole explanation. After cranial radiotherapy for a non-pituitary brain tumour, 88.8 per cent of 107 adults developed some pituitary hormone deficiency over a median eight years, with gonadotrophin deficiency in 34.6 per cent, and "incidence of all pituitary hormone deficiencies almost doubling between years 2 and 7 of follow-up". That last point is the practical one: a single normal result soon after treatment does not settle the question.

What replacement does and does not require. The Endocrine Society recommends diagnosing hypogonadism "only in men with symptoms and signs consistent with testosterone deficiency and unequivocally and consistently low serum T concentrations", confirmed on a repeat morning fasting sample, and recommends against starting it in men with breast or prostate cancer among other conditions. The American Urological Association uses a total testosterone below 300 nanograms per decilitre as a reasonable diagnostic cut-off, says clinicians "should inform patients of the absence of evidence linking testosterone therapy to the development of prostate cancer", and on the specific question says that men "with a history of prostate cancer should be informed that there is inadequate evidence to quantify the risk-benefit ratio of testosterone therapy". It advises aiming for a level in the middle of the normal range and measuring it every six to twelve months on treatment. That is an expert opinion, not a trial result, and the best primary evidence is a series of 82 hypogonadal men with prostate cancer given testosterone, whose authors wrote that their study "supports the hypothesis that testosterone therapy may be oncologically safe" but only "in the absence of randomized, placebo controlled trials".

On cardiovascular safety more generally, the TRAVERSE trial of 5,246 hypogonadal men with or at high risk of cardiovascular disease found testosterone non-inferior to placebo for major cardiovascular events, with a higher incidence of atrial fibrillation, acute kidney injury and pulmonary embolism. Men with prostate cancer were excluded, so it does not answer the prostate question.

What comes back, and when: testicular function after chemotherapy often recovers over one to three years and sometimes does not, and the deficiency after cranial radiotherapy accumulates rather than resolves. Testosterone replacement is a treatment that continues rather than a repair, and it suppresses sperm production, so anyone who may want children should have semen analysis and banking discussed before it starts.

## Fields

- Kind: Technology
- Status: established
- Last checked: 2026-10-02
- Tags: rejuvenation; survivorship; evidence:moderate
- Principle: Alkylating agents and radiation damage the Leydig cells that make testosterone and the germinal epithelium that makes sperm, the latter at much lower doses. Cranial irradiation damages the hypothalamic-pituitary axis progressively over years. Exogenous testosterone restores circulating hormone but suppresses gonadotrophins and therefore spermatogenesis, which is why fertility comes first in the conversation.
- Strengths: Prevalence is high and a blood test finds it; Clear diagnostic thresholds and monitoring intervals in two major guidelines; Symptoms, bone density, body composition and mood respond to correction of a genuine deficiency
- Limitations: No randomised evidence for replacement in men with a history of prostate cancer; Guidelines recommend against starting it in men with breast or prostate cancer; It suppresses sperm production, so fertility must be settled first

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Hypogonadism
- Adverse health outcomes in relationship to hypogonadism after chemotherapy: a multicentre study of testicular cancer survivors (JNCCN 2019): https://doi.org/10.6004/jnccn.2018.7109
- Pituitary dysfunction following cranial radiotherapy for adult-onset nonpituitary brain tumours (Clin Endocrinol 2016): https://doi.org/10.1111/cen.12969
- Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline (JCEM 2018): https://doi.org/10.1210/jc.2018-00229
- Evaluation and management of testosterone deficiency: AUA guideline (J Urol 2018): https://doi.org/10.1016/j.juro.2018.03.115
- Testosterone therapy in patients with treated and untreated prostate cancer: impact on oncologic outcomes (J Urol 2016): https://doi.org/10.1016/j.juro.2016.04.069
- TRAVERSE: cardiovascular safety of testosterone-replacement therapy (NEJM 2023): https://doi.org/10.1056/NEJMoa2215025

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- terms: [Erectile dysfunction after prostate cancer treatment](https://onco.cc/terms/erectile-dysfunction-after-prostate-cancer/), [Late effects and survivorship toxicity](https://onco.cc/terms/late-effects/)
- bottlenecks: [Survivorship and late effects are neglected](https://onco.cc/bottlenecks/b-survivorship/)

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