Androgen deprivation therapy and fracture risk in Chinese patients with prostate carcinoma

Conventional androgen deprivation therapy is associated with an increased risk of fracture in advanced prostate cancer, a nationwide population-based study

PURPOSE

Androgen deprivation therapy (ADT) is the standard of care in advanced prostate cancer. We conducted a Taiwan National Health Insurance Research Database (NHIRD) study to evaluate the association between ADT and fracture risk in patient with prostate cancer in Taiwan.

METHODS

Between 2001 and 2008, data from the Taiwan NHIRD was collected. We separated newly diagnosed prostate cancer patients into four groups: the injection of gonadotropin-releasing hormone agonists and antagonists group, the orchiectomy group, the oral antiandorgens group and the radical prostatectomy only group. A non-cancer matched control group was also assigned for comparison. T tests, chi-squared tests, multivariate Cox proportional hazard regression were performed. A subsequent fracture event was defined according to the appropriate diagnosis codes (ICD9-CM 800-829) with hospitalization. Patients with fracture before their diagnosis with prostate cancer were excluded.

RESULTS

Overall, 22517 newly diagnosed patients with prostate cancer were enrolled in the study. After exclusion criteria were applied, 13321 patients were separated into the injection group (5020 subjects), the orchiectomy group (1193 subjects), the oral group (6059 subjects) and the radical prostatectomy only group (1049 subjects). The mean age of the overall study population was 74.4 years. Multi-variant analysis disclosed a significantly increased risk of fracture in the injection group, the orchiectomy group, and the oral group (hazard ratio [HR] = 1.55, 95%, confidence interval [CI] 1.36 to 1.76, p<0.001, HR = 1.95, 95%, CI 1.61 to 2.37, p<0.001, HR = 1.37, 95%, CI 1.22 to 1.53, p<0.001, respectively). In contrast, a significantly decreased fracture risk was noted in the radical prostatectomy only group (HR = 0.51, 95%, CI 0.35 to 0.74, p = 0.001). Patients receiving osteoporosis medication had a significantly decreased fracture risk (HR = 0.26, 95%, CI 0.19-0.37, p<0.001).

CONCLUSIONS

ADT is associated with an increased risk of fracture. For patients receiving long-term prostate cancer castration therapy, doctors should always keep this complication in mind and arrange proper monitoring and provide timely osteoporosis medication.

Risk of Fracture During Androgen Deprivation Therapy Among Patients With Prostate Cancer: A Systematic Review and Meta-Analysis of Cohort Studies

Background: Androgen deprivation therapy (ADT) suppresses the production of androgen, and ADT is broadly used for intermediate or higher risk disease including advanced and metastatic cancer. ADT is associated with numerous adverse effects derived from the pharmacological properties. Previous meta-analysis on fracture risk among ADT users possessed limited data without further subgroup analysis. Risk estimation of updated real-world evidence on ADT-related fracture remains unknown. Objectives: To assess the risk of fracture and fracture requiring hospitalization associated with ADT among prostate cancer population on different disease conditions, treatment regimen, dosage level, fracture sites. Methods: The Cochrane Library, PubMed, and Embase databases were systematically screened for eligible cohort studies published from inception to March 2020. Two authors independently reviewed all the included studies. The risks of any fracture and of fracture requiring hospitalization were assessed using a random-effects model, following by leave-one-out, stratified, and sensitivity analyses. The Grading of Recommendations Assessments, Development and Evaluations (GRADE) system was used to grade the certainty of evidence. Results: Sixteen eligible studies were included, and total population was 519,168 men. ADT use is associated with increasing fracture risk (OR, 1.39; 95% CI, 1.26-1.52) and fracture requiring hospitalization (OR, 1.55; 95% CI, 1.29-1.88). Stratified analysis revealed that high-dose ADT results in an elevated risk of fracture with little statistical heterogeneity, whereas sensitivity analysis restricted to adjust for additional factors indicated increased fracture risks for patients with unknown stage prostate cancer or with no restriction on age with minimal heterogeneity. The GRADE level of evidence was moderate for any fracture and low for fracture requiring hospitalization. Conclusion: Cumulative evidence supports the association of elevated fracture risk with ADT among patients with prostate cancer, including those with different disease conditions, treatment regimens, dose levels, and fracture sites. Further prospective trials with intact information on potential risk factors on fracture under ADT use are warranted to identify the risky population.

Bone Fracture Incidence After Androgen Deprivation Therapy-Investigational Agents: Results From Cancer Therapy Evaluation Program-Sponsored Early Phase Clinical Trials 2006-2013

Introduction: Androgen deprivation therapy (ADT) is a primary treatment option for patients diagnosed with locally advanced-stage or metastatic prostate cancer. Androgen deprivation can be achieved either by radical orchiectomy or by medical castration using a gonadotropin-releasing hormone agonist. ADT has been linked to an initial 12-month loss of bone mineral density, a risk factor for weight-bearing bone fracture, and therefore, a confounding hazard for adverse event when patients are enrolled on early phase trials. To better understand the frequency of ADT-investigational agent-related bone fracture, we conducted a retrospective study of National Cancer Institute Cancer Therapy Evaluation Program (CTEP)-sponsored early phase trials to determine the number of fractures observed among enrolled prostate cancer patients. Patients and Methods: 464 locally advanced-stage or metastatic prostate cancer patients were identified among seven ADT-investigational agent trials conducted between 2006 and 2013. Demographic, co-morbidity, treatment, and adverse event variables were abstracted from CTEP databases and descriptive statistics were used. Results: 464 men had a median age of 64 years, were mostly white (90%), and had a performance status of 0 or 1 (98%). The number of new bone fractures occurring on or after ADT-investigational agent treatment was very low (4.6 per 1000 person-years). The median pretrial prostate specific antigen level was 29 ng/mL and most men (71%) had prostate cancer histopathology Gleason 7 score or higher. In these trials, 43 percent of men had bone only and 35 percent had bone and visceral metastatic disease. The most frequent grade 1 or 2 adverse events were fatigue (36%), hot flashes (27%), and anemia (17%). Grade 3 or higher adverse events were rare, with hypertension (3%) and hyperglycemia (3%) observed. Conclusions: Identifying bone health factors may still be relevant in selected early phase ADT-investigational agent trial patients, emphasizing the need for improved methods for capturing baseline bone health and studying ADT-investigational agent and concurrent medication interactions on bone health.

Androgens and Androgen Receptor Actions on Bone Health and Disease: From Androgen Deficiency to Androgen Therapy

Androgens are not only essential for bone development but for the maintenance of bone mass. Therefore, conditions with androgen deficiency, such as male hypogonadism, androgen-insensitive syndromes, and prostate cancer with androgen deprivation therapy are strongly associated with bone loss and increased fracture risk. Here we summarize the skeletal effects of androgens—androgen receptors (AR) actions based on in vitro and in vivo studies from animals and humans, and discuss bone loss due to androgens/AR deficiency to clarify the molecular basis for the anabolic action of androgens and AR in bone homeostasis and unravel the functions of androgen/AR signaling in healthy and disease states. Moreover, we provide evidence for the skeletal benefits of androgen therapy and elucidate why androgens are more beneficial than male sexual hormones, highlighting their therapeutic potential as osteoanabolic steroids in improving bone fracture repair. Finally, the application of selective androgen receptor modulators may provide new approaches for the treatment of osteoporosis and fractures as well as building stronger bones in diseases dependent on androgens/AR status.