Risk of low bone mineral density in testicular germ cell cancer survivors : Association with hypogonadism and treatment modality

The cure rate of testicular cancer exceeds 95%, but testicular cancer survivors (TCS) are at increased risk of hypogonadism (HG). It has been suggested that TCS have reduced bone mineral density (BMD), but it is unclear whether this is related to HG or a direct effect of cancer therapy. The aim of this study was to evaluate whether TCS have decreased BMD, and if BMD is related to HG and/or the cancer treatment given. We investigated 91 TCS (mean age at diagnosis: 31 years; mean 9.3 years follow-up) and equal number of age matched controls (mean age at inclusion 40.3 years and 41.2 years, respectively). Total testosterone and LH were measured. BMD was determined using dual-energy X-ray absorptiometry (DXA). Low BMD (LBD) was defined as Z-score <-1. Compared to eugonadal TCS, both TCS with untreated HG (mean difference: -0.063 g/cm2; 95% CI: -0.122; -0.004 p = 0.037) and TCS receiving androgen replacement (mean difference -0.085 g/cm2; 95% CI: -0.168; -0.003; p = 0.043) presented with statistically significantly 6-8% lower hip BMD. At the spine, L1-L4, an 8% difference reached the level of statistical significance only for those with untreated HG (mean difference: -0.097 g/cm2; 95% CI: -0.179; -0.014; p = 0.022). TCS with untreated HG had significantly increased OR for spine L1-L4 LBD (OR = 4.1; 95% CI: 1.3; 13; p = 0.020). The associations between the treatment given and BMD were statistically non-significant, both with and without adjustment for HG. In conclusion, TCS with HG are at increased risk of impaired bone health. Prevention of osteoporosis should be considered as an important part in future follow up of these men