33% radius evaluation to assess bone mineral density in prostate cancer patients

Bone Mineral Density of the 1/3 Radius Refines Osteoporosis Diagnosis, Correlates With Prevalent Fractures, and Enhances Fracture Risk Estimates

OBJECTIVE

To investigate the added value of 1/3 radius (1/3R) for the diagnosis of osteoporosis by spine and hip sites and its correlation with prevalent fractures and predicted fracture risk.

METHODS

Fracture Risk Assessment Tool (FRAX) scores for hip and major osteoporotic fractures (MOF) with/without trabecular bone score were considered proxy for fracture risk. The contribution of 1/3R to risk prediction was depicted via linear regression models with FRAX score as the dependent variable-first only with central and then with radius T-score as an additional covariate. Significance of change in the explained variance was compared by F-test.

RESULTS

The study included 1453 patients, 86% women, aged 66 ± 10 years. A total of 32% (n = 471) were osteoporotic by spine/hip and 8% (n = 115) by radius only, constituting a 24.4% increase in the number of subjects defined as osteoporotic (n = 586, 40%). Prior fracture prevalence was similar among patients with osteoporosis by spine/hip (17.4%) and radius only (19.1%) (P = .77). FRAX prediction by a regression model using spine/hip T-score yielded explained variance of 51.8% and 49.9% for MOF and 39.8% and 36.4% for hip (with/without trabecular bone score adjustment, respectively). The contribution of 1/3R was statistically significant (P < .001) and slightly increased the explained variance to 52.3% and 50.4% for MOF and 40.9% and 37.4% for hip, respectively.

CONCLUSION

Reclassification of BMD results according to radius measurements results in higher diagnostic output. Prior fractures were equally prevalent among patients with radius-only and classic-site osteoporosis. FRAX tool performance slightly improved by incorporating radius BMD. Whether this approach may lead to a better fracture prediction warrants further prospective evaluation.

Diffuse osteosclerosis in a patient with prostate cancer

A 61-year-old man was referred to our outpatient clinic because of severe bilateral upper leg pain for 1 year. On admission, the patient had anemia and a high serum alkaline phosphatase level. Lumbar and femoral neck T-scores were +10.5 and +9.6, respectively. His radius 33 % T-score was -2.8. Plain radiographs of the patient's pelvis, spine, and long bones revealed osteosclerosis. The patient had previously undergone a prostate biopsy, which showed prostate adenocarcinoma (Gleason score 3 + 4). The patient's total and free prostate-specific antigen were very high. According to previous records, the patient did not have anemia, and his serum alkaline phosphatase (ALP) level was normal. An abdominal radiograph taken 2 years earlier revealed a normal spine and pelvic bone. Bone scintigraphy yielded nontypical findings for prostate cancer metastasis. Computed tomography of the patient's thorax and abdomen showed heterogeneous sclerotic areas in all bones consistent with prostate cancer metastasis. A bone marrow biopsy disclosed disseminated carcinomatosis of bone marrow in association with prostate cancer. Clinicians should be aware of the possibility of prostate malignancy as a cause of high bone mineral density (BMD), even in the absence of typical localized findings on plain radiographs.

Changes in bone mineral density in men starting androgen deprivation therapy and the protective role of vitamin D

SUMMARY

Androgen deprivation therapy in 80 men was associated with declines in bone mineral density (BMD), which were greatest in the first year, and in the lumbar spine compared to controls. Vitamin D use was associated with improved BMD in the lumbar spine and in the first year.

INTRODUCTION

Decreased BMD is a common side effect of androgen deprivation therapy (ADT), leading to increased risk of fractures. Although loss of BMD appears to be greatest within the first year of starting ADT, there are few long-term studies of change in BMD, and risk factors for bone loss are not well-characterized.

METHODS

Men aged 50+ with nonmetastatic prostate cancer starting continuous ADT were enrolled in a prospective longitudinal study. BMD was determined by dual-energy x-ray absorptiometry at baseline and yearly for 3 years. Matched controls were men with prostate cancer not receiving ADT. Multivariable regression analysis examined predictors of BMD loss.

RESULTS

Eighty ADT users and 80 controls were enrolled (mean age 69 years); 52.5 % had osteopenia and 8.1 % had osteoporosis at baseline. After 1 year, in adjusted models, ADT was associated with significant losses in lumbar spine BMD compared to controls (-2.57 %, p = 0.006), with a trend towards greater declines at the total hip (p = 0.09). BMD changes in years 2 and 3 were much smaller and not statistically different from controls. Use of vitamin D but not calcium was associated with improved BMD in the lumbar spine in year 1 (+6.19 %, p < 0.001) with smaller nonsignificant increases at other sites (+0.86 % femoral neck, +0.86 % total hip, p > 0.10) primarily in the first year.

CONCLUSIONS

Loss of BMD associated with ADT is greatest at the lumbar spine and in the first year. Vitamin D but not calcium may be protective particularly in the first year of ADT use.

Skeletal complications of ADT: disease burden and treatment options

Therapy based on androgenic deprivation is one of the standard treatments that many prostate cancer patients receive. Moreover, its use is increasing owing to a clear expansion of the indications for this therapy in patients with localized prostate cancer. Despite classically being considered to be well tolerated, androgenic deprivation has adverse effects. Of these, the loss of mineral bone mass is particularly notable and can lead to osteoporosis, as well as an increased risk of bone fracture. Some fractures, such as hip fractures, may have serious consequences. Useful procedures such as bone densitometry can aid in the diagnosis of these conditions. Once diagnosed, decreases in mineral bone mass can be managed by dietary recommendations, general changes in lifestyle or medication. We review the most important randomized controlled trials evaluating different drugs (bisphosphonates, denosumab and toremifene) in the prevention of bone loss and in the reduction in fracture risk in prostate cancer patients treated with androgen-deprivation therapy. Following the applicable recommendations, urologists must carefully monitor the bone health of prostate cancer patients subjected to androgenic deprivation to obtain an early diagnosis and apply the appropriate general and/or therapeutic measures if necessary.