Effect of topical testosterone on pre-diabetes and diabetes.

Overview of: Bhasin S, Lincoff AM, Nissen SE, et al. Effect of testosterone on progression from prediabetes to diabetes in men with hypogonadism: a substudy of the TRAVERSE randomized clinical trial. JAMA Intern Med. 2024. doi: 10.1001/jamainternmed.2023.7862. [Epub ahead of print 5 February 2024].

Effects of gender affirming hormone therapy with testosterone on coagulation and hematological parameters in transgender people assigned female at birth: A systematic review and meta-analysis.

BACKGROUND: Hormone replacement therapy is associated with an increased thromboembolic risk. The effects of testosterone (T) on coagulation markers in people assigned female at birth (AFAB) under gender affirming hormone therapy (GAHT) are not well described. METHODS: Systematic review and meta-analysis on English-language articles retrieved from PubMed, Scopus and Cochrane Library up to April 2023 investigating T therapy in AFAB people. Coagulation parameters included international normalized ratio (INR), fibrinogen, activated partial thromboplastin clotting time (aPTT), plasminogen activator inhibitor-1 (PAI-1); hematological variables included hemoglobin (Hb) and hematocrit (HCT). We also reported the rate of thromboembolic events. Data were combined as mean differences (MD) with a 95 % confidence interval (CI) of pre- vs post-follow-up values, using random-effects models. RESULTS: We included 7 studies (6 prospective and 1 retrospective) providing information on 312 subjects (mean age: 23 to 30 years) who underwent GAHT with variable T preparation. T therapy was associated with a significant increase in INR values [MD: 0.02, 95 % confidence interval (CI): 0.01-0.03; p = 0.0001], with negligible heterogeneity (I2 = 4 %). T therapy was associated with increased Hb (MD: 1.48 g/dL, 95%CI: 1.17 to 1.78; I2 = 9 %) and HCT (4.39 %, 95%CI: 3.52 to 5.26; I2 = 23 %) values. No effect on fibrinogen, aPTT and PAI-1 was found. None of the study reported thromboembolic events during the follow-up. CONCLUSION: Therapy with T increased blood viscosity in AFAB men. A slight increase in INR values was also found, but the clinical relevance and mechanism(s) of this finding needs to be clarified.

Management of Male Fertility in Hypogonadal Patients on Testosterone Replacement Therapy.

Testosterone is crucial in regulating several body functions in men, including metabolic, sexual, and cardiovascular functions, bone and muscle mass, and mental health. Therefore, optimizing testosterone levels in men is an important step to maintaining a healthy body and mind, especially as we age. However, traditional testosterone replacement therapy has been shown to lead to male infertility, caused by negative feedback in the hypothalamic-pituitary-gonadal (HPG) axis. Recent advances in research have led to the discovery of many new methods of administration, which can have more or less suppressive effects on the HPG axis. Also, the usage of ancillary medications instead of or after testosterone administration might help maintain fertility in hypogonadal patients. The goal of this narrative review is to summarize the newest methods for optimizing fertility parameters in patients undergoing treatment for hypogonadism and to provide the necessary information for healthcare providers to make the right treatment choices.

Reproductive late effects and testosterone replacement therapy in male childhood cancer survivors: A population-based study (the Fex-Can study).

Childhood cancer survivors are at risk of various endocrine late effects affecting their quality of life. The aim of this study was to assess the prevalence and predictors of endocrine and reproductive outcomes in young adult survivors. A secondary aim was to assess possible associations between testosterone replacement therapy (TRT) and other endocrine, cardiovascular and psychosocial late effects. This nationwide study comprised 1212 male childhood cancer survivors aged 19-40 years, identified through the National Quality Registry for Childhood Cancer in Sweden. Median age at diagnosis during 1981-2017 was 7 (range 0-17) and at study 29 (19-40) years. The study combined self-report survey data with cancer treatment data from the national registry. Hormone-induced puberty was self-reported by 3.8% of the survivors and ongoing TRT by 6.0%. In separate logistic regression analyses, these treatments were associated with hematopoietic stem cell transplantation and cranial radiotherapy. Hormone-induced puberty was additionally associated with younger age at diagnosis. Men with TRT had a higher prevalence of other endocrine deficiencies, cholesterol medication, depressive symptoms and fatigue as well as a lower probability of living with a partner, having a biological child or current occupation. In the total male cohort, 28.2% reported having a biological child. Reassuring reproductive outcomes after less intensive therapies and low frequency of TRT were observed in young adult male childhood cancer survivors treated in the most recent treatment era. However, men with TRT suffered from several other endocrine, cardiovascular and psychosocial late effects, indicating a need for long-term monitoring of this high-risk group.

Endometrial Cancer in a Transgender Man with Prolonged Exogenous Testosterone Use.

BACKGROUND: Hormone therapy (HT) in transgender males requires monitoring. For amenorrheic transmasculine individuals on HT, episodes of abnormal vaginal bleeding should be assessed promptly. CASE: A 33-year-old transgender man on exogenous testosterone therapy for medical gender transition was found to have stage IV endometrioid endometrial adenocarcinoma. Surgical resection was performed for symptom control, and the patient was treated with palliative chemotherapy. The tumor was androgen receptor-negative, and, after a multidisciplinary discussion of the risks and benefits of continuing exogenous testosterone, testosterone therapy was restarted postoperatively. CONCLUSION: Long-term androgen use may have unknown implications for the development of malignancy, and treating reproductive organ cancer in transgender males may be complicated by the desire to continue androgen therapy.

Testosterone Treatment and Fractures in Men with Hypogonadism.

BACKGROUND: Testosterone treatment in men with hypogonadism improves bone density and quality, but trials with a sufficiently large sample and a sufficiently long duration to determine the effect of testosterone on the incidence of fractures are needed. METHODS: In a subtrial of a double-blind, randomized, placebo-controlled trial that assessed the cardiovascular safety of testosterone treatment in middle-aged and older men with hypogonadism, we examined the risk of clinical fracture in a time-to-event analysis. Eligible men were 45 to 80 years of age with preexisting, or high risk of, cardiovascular disease; one or more symptoms of hypogonadism; and two morning testosterone concentrations of less than 300 ng per deciliter (10.4 nmol per liter), in fasting plasma samples obtained at least 48 hours apart. Participants were randomly assigned to apply a testosterone or placebo gel daily. At every visit, participants were asked if they had had a fracture since the previous visit. If they had, medical records were obtained and adjudicated. RESULTS: The full-analysis population included 5204 participants (2601 in the testosterone group and 2603 in the placebo group). After a median follow-up of 3.19 years, a clinical fracture had occurred in 91 participants (3.50%) in the testosterone group and 64 participants (2.46%) in the placebo group (hazard ratio, 1.43; 95% confidence interval, 1.04 to 1.97). The fracture incidence also appeared to be higher in the testosterone group for all other fracture end points. CONCLUSIONS: Among middle-aged and older men with hypogonadism, testosterone treatment did not result in a lower incidence of clinical fracture than placebo. The fracture incidence was numerically higher among men who received testosterone than among those who received placebo. (Funded by AbbVie and others; TRAVERSE ClinicalTrials.gov number, NCT03518034.).

Cost-effectiveness of testosterone treatment utilising individual patient data from randomised controlled trials in men with low testosterone levels.

BACKGROUND: Testosterone is safe and highly effective in men with organic hypogonadism, but worldwide testosterone prescribing has recently shifted towards middle-aged and older men, mostly with low testosterone related to age, diabetes and obesity, for whom there is less established evidence of clinical safety and benefit. The value of testosterone treatment in middle-aged and older men with low testosterone is yet to be determined. We therefore evaluated the cost-effectiveness of testosterone treatment in such men with low testosterone compared with no treatment. METHODS: A cost-utility analysis comparing testosterone with no treatment was conducted following best practices in decision modelling. A cohort Markov model incorporating relevant care pathways for individuals with hypogonadism was developed for a 10-year-time horizon. Clinical outcomes were obtained from an individual patient meta-analysis of placebo-controlled, double-blind randomised studies. Three starting age categories were defined: 40, 60 and 75 years. Cost utility (quality-adjusted life years) accrued and costs of testosterone treatment, monitoring and cardiovascular complications were compared to estimate incremental cost-effectiveness ratios and cost-effectiveness acceptability curves for selected scenarios. RESULTS: Ten-year excess treatment costs for testosterone compared with non-treatment ranged between £2306 and £3269 per patient. Quality-adjusted life years results depended on the instruments used to measure health utilities. Using Beck depression index-derived quality-adjusted life years data, testosterone was cost-effective (incremental cost-effectiveness ratio <£20,000) for men aged <75 years, regardless of morbidity and mortality sensitivity analyses. Testosterone was not cost-effective in men aged >75 years in models assuming increased morbidity and/or mortality. CONCLUSIONS AND FUTURE RESEARCH: Our data suggest that testosterone is cost-effective in men <75 years when Beck depression index-derived quality-adjusted life years data are considered; cost-effectiveness in men >75 years is dependent on cardiovascular safety. However, more robust and longer-term cost-utility data are needed to verify our conclusion.

Testosterone replacement in men with sexual dysfunction.

BACKGROUND: Clinical practice guidelines recommend testosterone replacement therapy (TRT) for men with sexual dysfunction and testosterone deficiency. However, TRT is commonly promoted in men without testosterone deficiency and existing trials often do not clearly report participants' testosterone levels or testosterone-related symptoms. This review assesses the potential benefits and harms of TRT in men presenting with complaints of sexual dysfunction. OBJECTIVES: To assess the effects of testosterone replacement therapy compared to placebo or other medical treatments in men with sexual dysfunction. SEARCH METHODS: We performed a comprehensive search of CENTRAL (the Cochrane Library), MEDLINE, EMBASE, and the trials registries ClinicalTrials.gov and World Health Organization International Clinical Trials Registry Platform, with no restrictions on language of publication or publication status, up to 29 August 2023. SELECTION CRITERIA: We included randomized controlled trials (RCTs) in men (40 years or over) with sexual dysfunction. We excluded men with primary or secondary hypogonadism. We compared testosterone or testosterone with phosphodiesterase-5 inhibitors (PDEI5I) to placebo or PDE5I alone. DATA COLLECTION AND ANALYSIS: Two review authors independently screened the literature, assessed the risk of bias, extracted data, and rated the certainty of evidence (CoE) according to GRADE using a minimally contextualized approach. We performed statistical analyses using a random-effects model and interpreted them according to standard Cochrane methodology. Predefined primary outcomes were self-reported erectile dysfunction assessed by a validated instrument, sexual quality of life assessed by a validated instrument, and cardiovascular mortality. Secondary outcomes were treatment withdrawal due to adverse events, prostate-related events, and lower urinary tract symptoms (LUTS). We distinguished between short-term (up to 12 months) and long-term (> 12 months) outcomes. MAIN RESULTS: We identified 43 studies with 11,419 randomized participants across three comparisons: testosterone versus placebo, testosterone versus PDE5I, and testosterone with PDE5I versus PDE5I alone. This abstract focuses on the most relevant comparison of testosterone versus placebo. Testosterone versus placebo (up to 12 months) Based on a predefined sensitivity analysis of studies at low risk of bias, and an analysis combing data from the similar International Index of Erectile Function (IIEF-EF) and IIEF-5 instruments, TRT likely results in little to no difference in erectile function assessed with the IIEF-EF (mean difference (MD) 2.37, 95% confidence interval (CI) 1.67 to 3.08; I² = 0%; 6 RCTs, 2016 participants; moderate CoE) on a scale from 6 to 30 with larger values reflecting better erectile function. We assumed a minimal clinically important difference (MCID) of greater than or equal to 4. TRT likely results in little to no change in sexual quality of life assessed with the Aging Males' Symptoms scale (MD -2.31, 95% CI -3.63 to -1.00; I² = 0%; 5 RCTs, 1030 participants; moderate CoE) on a scale from 17 to 85 with larger values reflecting worse sexual quality of life. We assumed a MCID of greater than or equal to 10. TRT also likely results in little to no difference in cardiovascular mortality (risk ratio (RR) 0.83, 95% CI 0.21 to 3.26; I² = 0%; 10 RCTs, 3525 participants; moderate CoE). Based on two cardiovascular deaths in the placebo group and an assumed MCID of 3%, this would correspond to no additional deaths per 1000 men (95% CI 1 fewer to 4 more). TRT also likely results in little to no difference in treatment withdrawal due to adverse events, prostate-related events, or LUTS. Testosterone versus placebo (later than 12 months) We are very uncertain about the longer-term effects of TRT on erectile dysfunction assessed with the IIEF-EF (MD 4.20, 95% CI -2.03 to 10.43; 1 study, 42 participants; very low CoE). We did not find studies reporting on sexual quality of life or cardiovascular mortality. We are very uncertain about the effect of testosterone on treatment withdrawal due to adverse events. We found no studies reporting on prostate-related events or LUTS. AUTHORS' CONCLUSIONS: In the short term, TRT probably has little to no effect on erectile function, sexual quality of life, or cardiovascular mortality compared to a placebo. It likely results in little to no difference in treatment withdrawals due to adverse events, prostate-related events, or LUTS. In the long term, we are very uncertain about the effects of TRT on erectile function when compared to placebo; we did not find data on its effects on sexual quality of life or cardiovascular mortality. The certainty of evidence ranged from moderate (signaling that we are confident that the reported effect size is likely to be close to the true effect) to very low (indicating that the true effect is likely to be substantially different). The findings of this review should help to inform future guidelines and clinical decision-making at the point of care.

Testosterone replacement therapy: clinical considerations.

INTRODUCTION: As an increasingly popular therapeutic option, testosterone replacement therapy (TRT) has gained significant notoriety for its health benefits in indicated populations, such as those suffering from hypogonadism. AREAS COVERED: Benefits such as improved libido, muscle mass, cognition, and quality of life have led to widened public interest in testosterone as a health supplement. No therapy exists without side effects; testosterone replacement therapy has been associated with side effects such as an increased risk of polycythemia, benign prostate hypertrophy (BPH), prostate cancer, gynecomastia, testicular atrophy, and infertility. Testosterone replacement therapy is often accompanied by several prophylactic co-therapies aimed at reducing the prevalence of these side effects. Literature searches for sections on the clinical benefits and risks associated with TRT were performed to include clinical trials, meta-analyses, and systematic reviews from the last 10 years. EXPERT OPINION: Data from clinical studies over the last decade suggest that the benefits of this therapy outweigh the risks and result in overall increased quality of life and remission of symptoms related to hypogonadism. With this in mind, the authors of this review suggest that carefully designed clinical trials are warranted for the investigation of TRT in symptomatic age-related hypogonadism.

Vaginal Cuff Dehiscence in Transgender Patients After Minimally Invasive Hysterectomy.

STUDY OBJECTIVE: To compare rates of vaginal cuff dehiscence (VCD) in transgender patients with cisgender patients after minimally invasive hysterectomy (MIH). DESIGN: We performed a single-surgeon, retrospective cohort analysis comparing the rates of VCD in patients undergoing MIH for gender affirmation with other indications (benign, malignant, prophylactic) with our study surgeon between January, 2015, and December, 2021. SETTING: Major, urban, academic tertiary care hospital in the United States. PATIENTS: 166 patients met inclusion criteria with 49 of those patients undergoing MIH (29.5%) for gender affirmation. Of the remaining 117 patients, 92 (78.6%) underwent MIH for cancer, 15 (12.8%) for prophylaxis, and 10 (8.5%) for benign indications. INTERVENTIONS: Not applicable. MEASUREMENTS: We assessed included patients for baseline demographics, presence of risk factors for VCD, details of index hysterectomy, and details of cuff dehiscence events. MAIN RESULTS: Transgender patients tended to be younger at the time of surgery, but demographics were otherwise similar between both groups. Most transgender patients (n = 36, 73.5%) had both ovaries removed at the time of hysterectomy, 100% were on testosterone therapy pre- and postoperatively, and none used supplementary estrogen. Three of the 49 transgender patients (6.1%) experienced postoperative dehiscence of the vaginal cuff compared with 2 of the 117 cisgender patients (1.7%). This failed to reach statistical significance; however, our descriptive analysis showed that all cases of dehiscence in the cisgender group had identifiable precipitating factors (i.e., trauma). By comparison, all cases of dehiscence in the transgender group were spontaneous with few identifiable risk factors. CONCLUSION: Transgender patients undergoing MIH may be at increased risk of VCD, although the rarity of this surgical complication precluded determination of statistical significance in our data set. We propose testosterone exposure as a possible risk factor for VCD, although we cannot exclude other factors, such as young age, as drivers of VCD in this population. Future studies of biospecimens are needed to evaluate for cellular differences in these patients.

Rises in Hematocrit Are Associated With an Increased Risk of Major Adverse Cardiovascular Events in Men Starting Testosterone Therapy: A Retrospective Cohort Claims Database Analysis.

PURPOSE: Elevated hematocrit (Hct) can result in increased risk of major adverse cardiovascular events (MACE) in men receiving testosterone therapy (TTh). However, the impact of the magnitude of the change in Hct from baseline after starting TTh has never been assessed. MATERIALS AND METHODS: To assess whether an increase in Hct after initiating TTh is associated with an increased risk of MACE within 3 and 24 months of initiating TTh, we queried the TriNetX Research network database for men over the age of 18 with Hct values obtained within 6 months before starting TTh, and who had follow-up Hct measurements within 3 and 24 months after beginning TTh from 2010 to 2021. Men with and without a subsequent increase in Hct after initiating TTh were propensity matched. MACE was defined as myocardial infarction, stroke, or death. RESULTS: After matching, 10,511 men who experienced an any increase in Hct after initiating TTh and an equal number of controls who did have an increase in Hct were included. Compared to controls who did not have an increase in Hct after starting TTh, the men who had an increase in subsequent Hct had a significantly increased risk of MACE compared to men with no change in Hct. CONCLUSIONS: We demonstrate that increases in Hct from baseline are associated with increased risk of MACE, compared to men whose Hct remains stable while receiving TTh.

Growth hormone and testosterone delay vertebral fractures in boys with muscular dystrophy on chronic glucocorticoids.

Glucocorticoid use in Duchenne and Becker muscular dystrophy prolongs ambulation but cause significant skeletal toxicity. Our analysis has immediate clinical implications, suggesting that growth hormone and testosterone have a stronger effect prior to first and subsequent vertebral fracture, respectively, relative to bisphosphonates alone in children with dystrophinopathies on chronic glucocorticoids. PURPOSE: Glucocorticoids prolong ambulation in boys with Duchenne muscular dystrophy; however, they have significant endocrine side effects. We assessed the impact of growth hormone (GH), testosterone, and/or zoledronic acid (ZA) on vertebral fracture (VF) incidence in patients with dystrophinopathies on chronic glucocorticoids. METHODS: We conducted a longitudinal retrospective review of 27 males with muscular dystrophy. Accelerated failure time (AFT) models were used to estimate the relative time to VF while on GH, testosterone, and/or ZA compared to ZA alone. Results are reported as failure time ratio, where >1 indicates prolonged time versus <1 indicates shorter time to next VF. RESULTS: The prevalence of growth impairment was 96% (52% utilized GH), pubertal delay was 86% (72% utilized testosterone), and low trauma fractures were 87% (72% utilized ZA). Multivariable analysis of the AFT models showed that participants on either GH or testosterone treatment relative to ZA alone experienced prolonged time to next VF (1.253, P<0.001), with GH being the significant contributor when analyzed independently from testosterone (1.229, P<0.001). Use of ZA with GH or testosterone relative to ZA alone resulted in prolonged time to next VF (1.171, P<0.001), with testosterone being a significant contributor (1.130, P=0.033). CONCLUSION: GH and testosterone each decreased VF risk in patients independent of or in combination with ZA, respectively.

Prostate Safety Events During Testosterone Replacement Therapy in Men With Hypogonadism: A Randomized Clinical Trial.

Importance: The effect of testosterone replacement therapy (TRT) on the risk of prostate cancer and other adverse prostate events is unknown. Objective: To compare the effect of TRT vs placebo on the incidences of high-grade prostate cancers (Gleason score ≥4 + 3), any prostate cancer, acute urinary retention, invasive prostate procedures, and pharmacologic treatment for lower urinary tract symptoms in men with hypogonadism. Design, Setting, and Participants: This placebo-controlled, double-blind randomized clinical trial enrolled 5246 men (aged 45-80 years) from 316 US trial sites who had 2 testosterone concentrations less than 300 ng/dL, hypogonadal symptoms, and cardiovascular disease (CVD) or increased CVD risk. Men with prostate-specific antigen (PSA) concentrations greater than 3.0 ng/mL and International Prostate Symptom Score (IPSS) greater than 19 were excluded. Enrollment took place between May 23, 2018, and February 1, 2022, and end-of-study visits were conducted between May 31, 2022, and January 19, 2023. Intervention: Participants were randomized, with stratification for prior CVD, to topical 1.62% testosterone gel or placebo. Main Outcomes and Measures: The primary prostate safety end point was the incidence of adjudicated high-grade prostate cancer. Secondary end points included incidence of any adjudicated prostate cancer, acute urinary retention, invasive prostate surgical procedure, prostate biopsy, and new pharmacologic treatment. Intervention effect was analyzed using a discrete-time proportional hazards model. Results: A total of 5204 men (mean [SD] age, 63.3 [7.9] years) were analyzed. At baseline, the mean (SD) PSA concentration was 0.92 (0.67) ng/mL, and the mean (SD) IPSS was 7.1 (5.6). The mean (SD) treatment duration as 21.8 (14.2) months in the TRT group and 21.6 (14.0) months in the placebo group. During 14 304 person-years of follow-up, the incidence of high-grade prostate cancer (5 of 2596 [0.19%] in the TRT group vs 3 of 2602 [0.12%] in the placebo group; hazard ratio, 1.62; 95% CI, 0.39-6.77; P = .51) did not differ significantly between groups; the incidences of any prostate cancer, acute urinary retention, invasive surgical procedures, prostate biopsy, and new pharmacologic treatment also did not differ significantly. Change in IPSS did not differ between groups. The PSA concentrations increased more in testosterone-treated than placebo-treated men. Conclusions and Relevance: In a population of middle-aged and older men with hypogonadism, carefully evaluated to exclude those at high risk of prostate cancer, the incidences of high-grade or any prostate cancer and other prostate events were low and did not differ significantly between testosterone- and placebo-treated men. The study's findings may facilitate a more informed appraisal of the potential risks of TRT. Trial Registration: ClinicalTrials.gov Identifier: NCT03518034.

The use of post-cycle therapy is associated with reduced withdrawal symptoms from anabolic-androgenic steroid use: a survey of 470 men.

BACKGROUND: Anabolic-androgenic steroids (AAS) mimic the effects of testosterone and may include testosterone itself; they are used for body enhancement within the general population. AAS use has been linked with increased mortality, cardiovascular disease, mental health disorders, and infertility. AAS-induced hypogonadism can persist for an uncertain time period despite cessation, during which men may report physical and neuropsychiatric symptoms. In an attempt to mitigate these symptoms and expedite testicular recovery, many men self-administer post-cycle-therapy (PCT), typically involving human chorionic gonadotrophin (hCG) and selective oestrogen receptor modulators (SERMs), which are known to potently stimulate testicular function. However, this practice has no objective evidence of effectiveness to lessen the severity or duration of hypogonadal symptoms. METHODS: An anonymous survey of four-hundred-and-seventy men using AAS explored the symptoms they experienced when ceasing AAS use; the effect of PCT on relieving their symptoms, and their perceived role for health service support. RESULTS: The majority of respondents were white, aged 18-30 years old, and working in skilled manual work. 51.7% (n = 243) reported no issues with AAS use, but 35.3% reported increased aggression. 65.1% (n = 306) of respondents had attempted AAS cessation and 95.1% of these experienced at least one symptom upon AAS cessation. Low mood, tiredness and reduced libido were reported in 72.9%, 58.5% and 57.0% of men stopping AAS use, respectively, with only 4.9% reporting no symptoms. PCT had been used by 56.5% of respondents with AAS cessation and mitigated cravings to restart AAS use, withdrawal symptoms and suicidal thoughts by 60%, 60% and 50%, respectively. The effect of stopping AAS on body composition and recovery of testosterone or fertility was a concern in 60.5% and 52.4%, respectively. Most respondents felt PCT should be prescribed under medical supervision in the community. CONCLUSIONS: Our survey suggests that the majority of men stopping AAS use are using some form of PCT. Some self-reported symptoms of AAS-induced hypogonadism such as cravings to restart AAS use reduce by 60% and suicidal thoughts reduce by 50%. These individuals are concerned about the negative effect of AAS use and cessation. This study provides crucial information for planning future research to evaluate the effects of PCT on symptoms when men stop AAS use.

Testosterone replacement therapy is not associated with increased prostate cancer incidence, prostate cancer-specific, or cardiovascular disease-specific mortality in Finnish men.

BACKGROUND: Concerns have been expressed over the safety of testosterone replacement therapy (TRT) in men with late-onset hypogonadism (LOH). Previous studies have shown controversial results regarding the association of TRT with the risk of cardiovascular events or prostate cancer (PCa) incidence, aggressiveness, and mortality. This study explores the overall risk of PCa and risk by tumor grade and stage, as well as mortality from PCa and cardiovascular disease (CVD), among men treated with TRT compared to men without LOH and TRT use. MATERIALS AND METHODS: The study included 78,615 men of age 55-67 years at baseline from the Finnish Randomized Study of Screening for Prostate Cancer (FinRSPC). Follow-up started at randomization and ended at death, emigration, or a common closing date January 1st, 2017. Cox proportional hazards regression model with time-dependent variables and adjustment for age, trial arm, use of other medications, and Charlson comorbidity index was used. Comprehensive information on TRT purchases during 1995-2015 was obtained from the Finnish National Prescription Database. PCa cases were identified from the Finnish Cancer Registry and causes of death obtained from Statistics Finland. RESULTS: Over the course of 18 years of follow-up, 2919 men were on TRT, and 285 PCa cases were diagnosed among them. TRT users did not exhibit a higher incidence or mortality rate of PCa compared to non-users. On the contrary, men using TRT had lower PCa mortality than non-users (HR = 0.52; 95% CI 0.3-0.91). Additionally, TRT users had slightly lower CVD and all-cause mortality compared to non-users (HR = 0.87; 95% CI 0.75-1.01 and HR = 0.93; 95% CI 0.87-1.0, respectively). No time- or dose-dependency of TRT use was evident in any of the analyses. CONCLUSION: Men using TRT were not associated to increased risk for PCa and did not experience increased PCa- or CVD-specific mortality compared to non-users. Further studies considering blood testosterone levels are warranted.