The overall purpose of the study is to evaluate the effect of 12 months testosterone replacement therapy in testicular cancer survivors with mild Leydig Cell Insufficiency in order to reduce the risk of cardiovascular disease.

The primary study objective is to evaluate changes in insulin sensitivity. The secondary study objective is to evaluate changes in the prevalence of metabolic syndrome, body composition, systemic inflammation and symptoms of testosterone deficiency.

This is a single-center, randomized, double-blind, placebo-controlled intervention study, designed to evaluate the effect of testosterone replacement therapy in testicular cancer survivors with mild Leydig Cell Insufficiency.

70 subjects will be randomized to receive either testosterone replacement therapy or placebo. The subjects will be invited for an information meeting where informed consent is signed. If a subject is suitable for participation in the trial, subject will be randomized to testosterone replacement therapy or placebo and baseline investigations will be performed. Afterwards, a 52-weeks treatment period begins in which subjects receive a daily dose of testosterone or placebo. Dose adjustment will be made three times during the first 8 weeks of the study. Evaluation of primary and secondary endpoints will be performed after 26 weeks, at the end of treatment (52 weeks) and three months after completion of treatment (week 64).

Inclusion Criteria:

• Signed informed consent.
• Previous treatment for testicular cancer.
• No signs of relapse 1 year after last treatment (orchiectomy, radiotherapy, chemotherapy).
• Free testosterone < the age-adjusted median and > -2 standard deviations (SD) from the age-adjusted median and LH > 2 SD from the age-adjusted median.

Exclusion Criteria:

• Treatment with testosterone within the last 6 months.
• Contraindications to testosterone treatment (prostate cancer, prostate specific antigen (PSA)> 4 ng/mL), malignancy suspect prostate by digital rectal examination, Alanine aminotransferase (ALT)> 1.5 upper reference level, Erythrocyte Volume Fraction (EVF) > 50%.
• Breast cancer.
• Symptomatic obstructive sleep apnoea syndrome
• Heart failure > NYHA II.
• Uncontrolled hypertension: (Systolic blood pressure > 160 mm Hg despite antihypertensive treatment, measured at two separate occasions)
• Inability to understand information about the trial
• Participation in any other clinical trial
• Allergy for the active substance or additives in Tostran or placebo.
• Known diabetes mellitus, or diabetes mellitus detected at screening or baseline tests.