Karnes, J.

e17540 Background: The clinical course in metastatic castrate-resistant prostate cancer (mCRPC) can be complicated when patients have disease progression after treatment with 2nd generation hormone therapy (2nd-HT), such as enzalutamide or abiraterone. Currently, limited data exist regarding the optimal choice of chemotherapy for mCRPC after failing 2nd-HT. We sought to evaluate three common chemotherapy regimens in this setting. Methods: We retrospectively identified 150 patients with mCRPC with disease progression on enzalutamide or abiraterone. 92 patients were chemo-naïve, while 58 patients had previously received docetaxel chemotherapy prior to 2nd-HT. After failing 2nd-HT, 90 patients received docetaxel-alone (group A), 33 patients received carboplatin plus docetaxel (group B), while 27 patients received cabazitaxel-alone (Group C). Favorable response was defined by ≥50% reduction in PSA level from baseline after a complete course of chemotherapy. Survival outcome was assessed for 30-month overall survival. Results: Mean (SD) age was 71.2 (8.28), 69.5(8.38) and 67.2 (8.36) for group (A), (B) and (C), respectively. Mean (SD) pre-chemotherapy PSA was 63.8 (138.18), 58.5 (118.15) and 53.7 (88.15) for group (A), (B) and (C), respectively. Mean (SD) Gleason score was 7.9 (1.1), 8.4 (0.88) and 8.1 (1.06) for group (A), (B) and (C), respectively. Patients in group (B) were 2.6 times more likely to have a favorable response compared to group (A) (OR = 2.625, 95%CI: 1.15 - 5.99) and almost 3 times compared to patients in group (C) (OR = 2.975, 95%CI: 1.04 – 8.54) (p-value = 0.0442). We report a Hazard Ratio (HR) of 3.1 (95% CI 1.31-7.35; p = 0.0037) between patients in group (A) versus group (B), and a HR of 4.18 (95% CI 1.58-11.06; p = 0.0037) between patients in group (C) versus group (B). Thirty-month overall survival was 70.7%, 38.9%, and 30.3% for group (B), (A), and (C) respectively (p-value = 0.008). Conclusions: Our data demonstrate improved response and cancer-specific survival in patients with treatment-refractory mCRPC on docetaxel plus carboplatin compared to docetaxel or cabazitaxel alone. Selection bias is inherent in any retrospective study; however, our finding suggests that clinicians may consider docetaxel plus carboplatin in mCRPC patients who fail 2nd-HT. Further prospective studies are warranted.

5577 Background: Prostate specific antigen (PSA) has well-recognized limitations as a marker for treatment response and disease progression. A post hoc analysis of the PREVAIL trial reported 24.5% of chemotherapy naïve mCRPC patients on enzalutamide had radiographic progression on conventional imaging with non-rising PSA. In this study, we sought to retrospectively compare PSA levels with C-11 choline positron emission tomography/ computed tomography (PET/CT) images in patients with m-CRPC on 2nd-HT with prior use of chemotherapy. Methods: We identified 123 patients with mCRPC on 2nd-HT following prior use of docetaxel chemotherapy (Abiraterone, n = 106; Enzalutamide, n = 17). Patients underwent serial PSA testing and C-11 choline PET/ CTs every 3–6 months. Disease progression was defined by the increase in blood pool corrected maximum standardized uptake value (SUVmax) of the index lesion on C-11 choline PET/CT scan. Suspicious lesions were confirmed by biopsy and/or conventional imaging. Results: Approximately 43% (n = 53) of patients had radiographic disease progression while on 2nd-HT. At time of radiographic progression, 60.4% of patients showed a parallel rise in PSA (Group-A), while 39.6% showed a paradoxical response; defined as radiographic progression with stable or down-trending PSA (Group-B). Median PSA at time of progression was 3.1 ng/ml for Group-A, and 1.3 ng/ml for Group-B (p-value = 0.0176). Median SUVmax was the same (4.9 Group-A, 4.6 Group-B; p-value = 0.6072). Bone-predominance progression was more significant in Group-B (90%) versus Group-A (65%) (p-value = 0.0309). The median time for radiographic progression was 9.5 months versus 3.9 months for Group-A and Group-B, respectively (Log-Rank = 0.0063). Conclusions: Metabolic imaging is a useful tool that should complement PSA in the evaluation of treatment response and disease progression in mCRPC patients on 2nd-HT, especially considering the paradoxical response observed in our data.

144 Background: Despite having well-recognized limitations, urologists often rely on serial PSA testing as a marker for treatment response or disease progression. To determine if PSA was indeed a reliable marker for treatment response or disease progression, we compared PSA levels against C-11 choline PET/CT in the evaluation of patients with advanced prostate cancer treated with second generation hormonal therapy (2nd-HT). Methods: We retrospectively identified 239 patients who were undergoing treatment with 2nd-HT (enzalutamide or abiraterone) for advanced prostate cancer. While on treatment, patients underwent serial PSA testing and C-11 choline PET/ CTs every 3 – 6 months. Paradoxical response was defined as increasing blood pool-corrected SUVmax of known choline-avid lesions and/or identification of new choline-avid lesions, despite stable or down-trending PSA. Results: Median (IQR) age was 70.4(64.3 – 75.7) years and median (IQR) primary Gleason Score was 8 (7 – 9). In our study, 19% of patients (n = 46/239) who were receiving 2nd-HT exhibited paradoxical response. Median (IQR) PSA and corrected SUVmax at baseline evaluation were 1.3 ng/mL (0.3 – 12.8 ng/mL) and 3.5 (1.8 – 5.8), respectively. Median (IQR) PSA and corrected SUVmax at the time of paradoxical response were 0.4 ng/mL (0.1 – 5.4 ng/mL) and 4.5 (2.8 – 6.8), respectively. The median duration of 2nd-HT treatment prior to detection of paradoxical response was 4.8 months (2.9 – 10.1 months). No significant difference was noted between patients receiving enzalutamide versus abiraterone (p = 0.35). Independent predictors of paradoxical response were prior primary systemic treatment (i.e. hormonal/chemo-hormonal therapy versus local therapy) and patient’s age at time of 2nd-HT initiation on univariate and multivariate analysis. Conclusions: Our retrospective review demonstrated prostate cancer disease progression discordant with PSA down-trending in 19% of patients receiving 2nd-HT. We conclude that in this subset of patients with advanced prostate cancer, PSA may not be a reliable marker of treatment response of disease progression, and routine radiographic evaluation in these patients is warranted.

367 Background: While neoadjuvant chemotherapy (NAC) for muscle−invasive bladder cancer (MIBC) is recognized as the standard of care, the management of patients with locally advanced and/or nodal disease after NAC and radical cystectomy (RC) is not well defined. We sought to evaluate the association of adjuvant chemotherapy (AC) and overall survival (OS) among patients with adverse pathology after NAC and RC. Methods: The National Cancer Database was reviewed to identify patients with adverse pathology (pT3N0, pT4N0, or pTanyN1−3) at RC following NAC from 2006−2012. Patients were stratified by receipt of AC. Clinical and pathologic variables were abstracted. OS was the primary end−point and differences on the basis of AC were assessed by the Kaplan−Meier method and log−rank test. Multivariable Cox proportional hazards regression was used to assess the association of AC with OS controlling for age, sex, race, Charlson score, year of diagnosis, pathologic stage, and receipt of adjuvant radiotherapy. Results: Adverse pathology following NAC and RC was identified in 1,361 patients from 2006−2012, of whom 328 (24.1%) received AC. Staging was pT3N0 in 444 (32.6%), pT4N0 in 162 (11.9%), and pTanyN1−3 in 755 (55.5%). Median OS for the entire cohort was 22.9 months, which differed by pathologic stage: 34.6 months (pT3N0), 21.4 months (pT4N0), and 19.3 months (pTanyN1-3)(p < 0.01). No difference in OS was noted by receipt of AC in the overall cohort (median OS 24.6 months with AC vs 22.0 months without AC; p = 0.18), or when stratified by pathologic stage. On multivariable analysis, receipt of AC was not significantly associated with overall mortality (HR 0.86; 95%CI 0.74−1.01; p = 0.06) for all patients. When stratified by stage, AC was associated with a significantly decreased risk of mortality among patients with pT4N0 disease (HR 0.56; 95%CI 0.33−0.97; p = 0.04), but not pT3N0 or pTanyN1−3 (p > 0.05). Conclusions: Patients with adverse pathology at RC after NAC have a median OS of approximately 2 years. AC was not associated with improved survival, except in the subgroup with pT4N0 disease. Clinical trials with newer systemic therapies are warranted for patients in this setting.

355 Background: While neoadjuvant chemotherapy (NAC) prior to radical cystectomy (RC) improves survival compared to RC alone for urothelial carcinoma of the bladder (UCB), the bulk of this survival benefit has been attributed to patients who achieve ypT0 status at RC. The implications of having residual UCB (rUCB) at RC after NAC are less clear. As such, we evaluated whether the outcomes for patients with rUCB after NAC differ from stage-matched RC patients who did not receive NAC. Methods: Patients undergoing RC for UCB between 1981-2010 at Mayo Clinic were identified. All RC pathology was re-reviewed by a single genitourinary pathologist. Patients who received NAC were matched 1:2 to patients not exposed to NAC based on pT and pN-stage, margin status, and year of RC. Kaplan Meier and Cox regression analyses were used to evaluate the associations between NAC and cancer-specific (CSS) and overall survival (OS), stratified by presence of rUCB (i.e. (y)pT0N0 and non-(y)pT0N0). Results: We matched 111 patients who underwent NAC + RC to 222 RC-alone patients. Median age was 68 years (IQR 60,74); 59 (18%) were female. Median follow-up among survivors was 7.2 years (IQR 6,16). A total of 248 patients died; 148 died from UCB. In patients without rUCB at RC, there were no differences in 5-yr CSS (86% vs. 90%, p=0.85) or OS (82% vs. 84%, p=0.46) between patients who did and did not receive NAC. Moreover, on multivariable analysis, NAC exposure was not associated with CSS (HR=1.0; 95%CI 0.3-3.1; p=0.9) or OS (HR=0.9; 95%CI 0.4-1.9; p=0.8) in this subgroup. Among patients with rUCB, receipt of NAC was associated with significantly worse 5-yr CSS (32% vs. 56%, p<0.001) and OS (25% vs. 48%, p<0.001). NAC exposure remained independently associated with worse CSS (HR=2.2; 95%CI 1.6-3.1; p<0.001) and OS (HR=2.0; 95%CI 1.5-2.7; p<0.001) among these patients. Conclusions: While patients who achieve a complete response to NAC have excellent survival outcomes, patients with residual UCB at RC after NAC have a worse prognosis compared to stage-matched RC patients not exposed to NAC. Such patients should be considered for enrolment in novel adjuvant therapy trials.

312 Background: Radical cystectomy (RC) is a preferred option for high−grade non−muscle invasive bladder cancer (HG NMIBC), particularly after failure of intravesical therapy. However, clinicians may be reluctant to offer surgery to older patients with NMIBC given concerns regarding morbidity. We therefore sought to evaluate the association of age with use of RC and clinicopathologic outcomes after RC for HG NMIBC. Methods: The National Cancer Data Base was queried to identify patients diagnosed with HG NMIBC between 2004−2013. Patients were stratified according to age at diagnosis: <60, 61−70, 71−80, >80 years. Multivariable logistic regression was performed to assess the associations of age group with utilization of RC and with pathologic upstaging (pT2−4 or pN+). Overall survival (OS) was evaluated using unadjusted and inverse propensity score weighted (IPTW) Kaplan−Meier methods and compared with the log-rank test. Results: RC was performed in 3,641 (5.7%) of 63,402 patients with HG NMIBC. Utilization of RC remained relatively constant over the study period (4.3%−6.8%; p=0.44). On multivariable analysis, increasing age was inversely associated with RC utilization, with the lowest utilization in those >80 (2.1% rate; OR 0.24; p<0.01). Similar associations of age with RC were observed at high volume centers (> 15 cases/year), academic centers, and for patients with cT1 disease. Among patients who underwent RC, pathologic upstaging was identified in 1,445 (43.6%), and no significant association was noted with age. NMIBC pathologic tumor stage was associated with improved OS compared to progression to pT2−4 or N+ disease at RC for all age groups: median OS improvement not reached in those under 60; 32 months in those 61−70; 55 months in those 71−80; and 34 months in those over 80 (all p<0.01). Similar improvements in survival were noted after IPTW. Conclusions: Older patients are significantly less likely to receive RC for HG NMIBC, despite a similar risk of upstaging and an improved survival when pathologic NMIBC is found at RC. These data support the use of RC for HG NMIBC in well selected patients across age strata.

241 Background: Androgen deprivation represents the standard treatment for PCA with osseous metastases. We explored the role of cRP in the largest cohort of contemporary patients with mPCA treated in 4 tertiary referral centres. Methods: A total of 114 patients with mPCA, lymph node, osseous or visceral metastases underwent cRP. Surgery related complications (Clavien-Dindo classification) and functional outcome were analysed. Oncologic outcome parameters such as cancer specific & overall survival as well as biochemical and clinical-free survival were evaluated using descriptive statistical analysis. Results: Mean patient age was 61 (42-69) years. Mean and median follow-up was 39.7 months (7-75) and 47 months (28-96), resp. 93 (81.6%) and 21 (18.4%) patients had low volume and high volume mets, resp.,. 80(70.2%) pts underwent neoadjuvant ADT with LHRH analogues. Surgical approach was open retropubic RP in 104 (92%) pts and 2 (1.8%), 10 (8.8%) and 101 (89.4%) pts underwent no, limited or extended pelvic LAD, resp. Adjuvant therapy was delivered in 99 (86.8%) pts. Pathohistology revealed significant vital PCA in 100% of cases: n = 16 (14.0%) exhibited pT4a, n = 21 (18.4%) had pT2 and the remainder had pT3a/b PCA. Positive lymph nodes or positive surgical margins were identified in 61.6% and 36.8%, resp.. 110 (96.5%) are alive and 66.7% are relapse-free. 74 (64.9%) pts did not experience any surgery related complications; 15 (13.1%) pts experienced Clavien Dindo grade IIIb/IV complications and underwent reintervention. Low versus high volume (32.2% vs 50%, p = 0.03), PSA at cRP < 1ng/ml vs PSA > 4 ng/ml, (18.9% vs 45.6%, p = 0.02) were associated with relapse. Low vs high volume disease (7.1% vs 32.1%), PSA < 4ng/ml vs PSA > 4 ng/ml (6.1% vs 47.8%) and neoadjuvant vs no neoadjuvant therapy (8.75% vs 24.2%) were associated with Clavien-Dindo IIIB complications (p < 0.05). Conclusions: cRP is feasible in men with mPCA independent on the extent of disease with a low rate of significant complications and good functional outcome. About two thirds of the patients remain relapse-free after a median follow-up of close to 4 years. cRP might be an individualized treatment option in the multimodality management of mPCA.