Incidence of Skeletal-Related Events in Patients With Advanced and Metastatic Prostate Cancer Treated With Hormone Therapy in a Low- and Middle-Income Country

16 Background: Skeletal-related events (SREs) are fractures, radiotherapy to bone, or spinal cord compression that occurs concurrently with or after the first bone metastasis in men with prostate cancer (PC) and may result from hormone therapy (HT). In this work, we report the incidence of SREs in patients with PC who are treated with HT and highlight the burden of advanced and metastatic PC in a practice in a low- and middle-income country. Methods: Retrospective data was of newly diagnosed patients with PC with SREs who were treated with androgen deprivation therapy at the University of Abuja Teaching Hospital, Abuja, Nigeria, between January 2012 and December 2015. Results: Of 219 cases reviewed, 142 patients (64.8%) had American Joint Committee on Cancer stage IV PC and so commenced treatment with HT, with > 50% of these patients being older than 65 years (mean [standard deviation], 68.3 [± 9.5] years). Serum prostate-specific antigen range was 1.4 to 2,461.58 ng/mL (mean [standard deviation], 113.7 [± 288.9] ng/mL). Twenty-nine patients (20.5%) had one or more SREs: spinal cord compression (19.1%), pathological fractures (1.4%), and radiotherapy to the affected bone (1.4%) being the most common. Fifty additional patients (35.2%) had bone pain with localization to the lumbosacral spine in > 50% of them, whereas two patients with pathologic fractures had internal fixation and bone radiotherapy, respectively. HT was orchiectomy, luteinizing hormone-releasing hormone agonists (LHRH), antiandrogens, and complete androgen blockade (orchiectomy plus antiandrogens) in 14 (9.8%), 3 (2.1%), 44 (30.9%), and 81 (57%) patients, respectively. Conclusion: That 65% of our patients had advanced or metastatic PC at first diagnosis lends credence to late presentation with increased morbidity and mortality of PC in our environment where penetration of radiotherapy services and access to LHRH is significantly low, as evidenced by patients who had complete androgen blockade that was treated with orchiectomy plus antiandrogens. AUTHORS' DISCLOSURES OF POTENTIAL CONFLICTS OF INTEREST No COIs from either author.

Complete androgen blockade as second-line hormone manipulation and delay of chemotherapy in metastatic prostate cancer

e16141 Background: Complete androgen blockade (CAB) after failure of castration or androgen receptor blocker (ARB) has not shown to prolong survival in patients with metastatic prostate cancer, unlike docetaxel-based chemotherapy. The widely variable clinical benefit seen with CAB as second-line hormone manipulation still justifies the identification of the patients to whom it should be offered. Objective: to evaluate progression-free survival (PFS) and overall survival (OS) in patients treated with CAB after failure of castration or ARB and to identify clinical predictors of benefit. Methods: We performed a retrospective analysis of all patients with metastatic prostate cancer treated with CAB as second-line hormone manipulation in a single institution after September 2005. OS and PFS were estimated using Kaplan-Meyer plots. We identified 78 patients and evaluated correlations of prostate specific antigen (PSA), Gleason scores, age, type and length of first-line hormone manipulation with OS and PFS during CAB. Fifty-four patients had failed castration and 24 had failed ARB. Forty-four patients received chemotherapy after failing CAB. Results: With a median follow-up of 21 months, median PFS with CAB was 12 months (CI 6.8–17.2). We did not find any correlation of PFS with type of first-line hormone manipulation (castration vs ARB, p = 0.10), age group (≤70 or >70 years old, p = 0.10), level of PSA at diagnosis (≤50 or >50 ng/mL, p = 0.17) or length of first-line hormone manipulation (≤14m vs >14 m, p = 0.78). There was no significant correlation between PFS and Gleason score at diagnosis (score ≤7 or >7, p = 0.25), nor between the level of testosterone at the beginning of CAB and PFS. Median OS for patients on CAB after failing castration was 36 months (CI 24–48), and median OS of patients on chemotherapy was not reached at 9.5 months follow-up. Conclusions: Based on a PFS of 12 months, OS of 36 months and good patient tolerance, we believe CAB should still be used in CRPC, prior to initiation of chemotherapy. Predictors of clinical benefit are still to be identified. No significant financial relationships to disclose.