Thompson, R. Houston

416 Background: Urethral recurrence (UR) has been reported to occur in up to 5% of patients following radical cystectomy (RC). Debate continues regarding the utility of screening for UR after RC. Moreover, oncologic outcomes of patients with UR remain incompletely described, and reports have been limited by small cohort sizes. Herein, we evaluated risk factors for UR as well as cancer-specific survival (CSS) and overall survival (OS) among patients with UR. Methods: We reviewed our institutional RC registry to identify patients with UR following RC. Logistic regression was used to assess risk factors for UR. Kaplan-Meier and Cox proportional hazard regression were used to compare outcomes in those with UR diagnosis prompted by symptoms versus those with asymptomatic UR diagnosed on surveillance cytology. Results: Overall, 2930 patients underwent RC from 1980-2018, with a median post-operative follow-up of 4.9 years (IQR 1.6-11.0), of whom 144 (4.9%) were subsequently diagnosed with UR. Prostatic urethral involvement at RC (odds ratio [OR] 5.75 [3.67-9.01], p < 0.0001) and higher pT-stage (OR 3.57 [2.07-6.14], p < 0.0001) were associated with an increased risk of UR, whereas receipt of continent urinary diversion (OR 0.34 [0.20-0.58], p < 0.0001) was associated with a decreased risk of UR. A total of 72/144 (50%) patients were diagnosed with UR based on symptoms, and 104/144 (72.2%) patients with UR underwent subsequent urethrectomy. Patients with symptomatic recurrence had higher tumor stage on urethrectomy than those with asymptomatic recurrence (≥pT2 in 13.1% vs 3.1%, p = 0.007). At a median follow-up of 2.6 years (IQR 1.0-7.1) after UR, 68 of the patients with UR died of urothelial carcinoma. Kaplan-Meier analyses suggest longer median overall and cancer-specific survival for patients with UR detected by cytology than those presenting with symptoms (p = 0.05 for both). On multivariable analyses, patients who experienced UR had significantly increased risk of cancer-specific (hazard ratio [HR] 1.93 [95% confidence interval 1.50-2.50), p < 0.0001) and all-cause mortality (HR 1.34 [1.13-1.65], p = 0.001). Conclusions: Approximately 5% of patient undergoing RC experience UR, with higher pT-stage and prostatic urethral involvement increasing the risk of UR. Asymptomatic detection of UR was associated with lower pathologic stage at urethrectomy as well as longer cancer-specific and overall survival, supporting urethral surveillance after RC.

Significance Statement Predicting outcomes on the basis of renal histology after a radical nephrectomy has been limited to studies with small sample sizes, short follow-ups, and only a descriptive characterization of histology. In this study of 936 patients followed up for a median of 6.4 years after establishing a new baseline kidney function following radical nephrectomy, the authors used morphometric methods to quantitatively characterize microstructural features on large renal wedge sections. Findings of larger nephrons and more extensive glomerulosclerosis and interstitial fibrosis predicted progressive CKD; interstitial fibrosis also predicted mortality from causes other than cancer. These findings provide insight into the important microstructural features of “generic” CKD in patients without a specific kidney disease and support the use of quantitative methods to evaluate renal histology after a radical nephrectomy to determine patients’ long-term risks. Background Nephron hypertrophy and nephrosclerosis may be important determinants of CKD and mortality. However, studies of outcomes associated with these microstructural features have been limited to small tissue specimens from patients selected for either good kidney health or known kidney disease. Methods To determine whether microstructural features are predictive of progressive CKD and mortality outcomes, we studied patients who underwent a radical nephrectomy for a tumor. Large wedge sections of renal parenchyma distal to the tumor were stained and scanned into high-resolution images; we annotated the cortex and all glomeruli to calculate glomerular volume, cortex volume per glomerulus, and percentage of globally sclerotic glomeruli. Morphometric measurements also included percentages of artery luminal stenosis and interstitial fibrosis/tubular atrophy (IF/TA) of the cortex. At follow-up visits every 6–12 months, we determined which patients experienced progressive CKD (defined as dialysis, kidney transplantation, or a 40% decline from postnephrectomy eGFR). Cox models for these outcomes were adjusted for age, sex, body mass index, hypertension, diabetes, smoking, eGFR, and proteinuria. Results Among 936 patients (mean age, 64 years; postnephrectomy baseline eGFR, 48 ml/min per 1.73 m 2 ), 117 progressive CKD events, 183 noncancer deaths, and 116 cancer deaths occurred during a median follow-up of 6.4 years. Larger glomerular volume, larger cortex per glomerulus, and higher percentage of globally sclerotic glomeruli or IF/TA predicted progressive CKD. Higher percentage IF/TA also predicted noncancer mortality. Microstructural features did not predict cancer mortality or recurrence. Conclusions After a radical nephrectomy, larger nephrons and nephrosclerosis predicted progressive CKD, and IF/TA predicted noncancer mortality. Morphometric analysis of renal parenchyma can predict noncancer clinical events in patients long after their radical nephrectomy.

e16103 Background: At present, androgen ablation (AA) therapy ± radiation therapy represents a first-line treatment for patients with unresectable locally advanced prostate cancer (CAP), typically resulting in palliative disease control. Immunotherapy, in the form of CTLA-4 blockade, has been shown to potentiate T-cell responses, representing a potential antitumoral immunotherapy for treating CAP. Here, we discuss the outcomes of 5 locally advanced CAP patients treated with the monoclonal antibody MDX-CTLA-4 (MDX-010) + AA who subsequently underwent radical prostatectomy (RP), 2 of whom exhibited striking down-staging of their disease. Methods: A Phase II trial testing AA + MDX-010 therapy for treatment of locally or systemically advanced CAP is currently ongoing at our institution. To date, 5/85 patients have electively opted for off-study RP with extended pelvic lymphadenectomy after documentation of robust treatment response by PSA, staging digital rectal exam, and 3-D imaging. Results: All men had unresectable, locally advanced disease (stage T2c-T4) prior to treatment with AA + MDX-010 and subsequently underwent RP. Median blood loss was 400mL (400–900). All patients had negative surgical margins. Of the 5 patients, 2 exhibited dramatic and indisputable down-staging of their disease. These two patients presented with 80% of biopsies involved with cancer, extraprostatic extension, seminal vesicle (SV) invasion, and bladder base involvement. On final pathology, both exhibited extensive treatment effect, remission of SV involvement, and robust disaggregation of solid tumors resulting in only microscopic, non-contiguous foci of residual intraprostatic cancer. Both had T4 disease pre-treatment, and had stage T2c on final pathology. One patient is free of disease with undetectable PSA for 19 months following adjuvant radiation treatment but no further therapy, while the other patient is awaiting follow-up. Conclusions: We have been able to demonstrate true down-staging of locally advanced prostate cancer with neoadjuvant AA + MDX-010 therapy. This therapeutic modality exhibits significant promise for men with unresectable disease and may provide durable and potentially curative cancer control. No significant financial relationships to disclose.

ObjectivesTo evaluate the timing and distribution of first renal cell carcinoma metastasis after nephrectomy stratified by nodal status.MethodsWe evaluated patients treated with nephrectomy for sporadic, unilateral renal cell carcinoma between 1970 and 2011 who subsequently developed distant metastasis to three or fewer sites. Site‐specific metastases‐free 2‐year survival rates were estimated using the Kaplan–Meier method. Associations of nodal status with time to metastasis were evaluated using multivariable Cox regression models.ResultsA total of 1049 patients met the inclusion criteria (135 pN1, 914 pN0/x patients). The median time to identification of first distant metastasis for pN1 patients was 0.4 years (interquartile range 0.2–1.1 years) versus 2.2 years (interquartile range 0.6–6.0 years) in pN0/x patients. The most common site of metastasis was to the lung, but this occurred earlier in pN1 patients (median 0.3 years vs 2.0 years). pN1 was associated with significantly lower site‐specific 2‐year metastases‐free survival when compared with pN0/x for lung (37% vs 70%, P < 0.001), bone (63% vs 87%, P < 0.001), non‐regional lymph nodes (60% vs 96%, P < 0.001) and liver metastases (79% vs 91%, P < 0.001). On multivariable analysis, pN1 status remained significantly associated with lung, bone, and non‐regional lymph node (all P < 0.001) metastases, but it was no longer associated with liver metastases (P = 0.3).ConclusionspN1 nodal status in M0 patients treated with nephrectomy for renal cell carcinoma is associated with more frequent early metastasis to sites conferring poor prognosis when compared with pN0/x. Our findings highlight the importance of rigorous, early surveillance though the multimodal use of a comprehensive history, physical, laboratory and radiological studies, as outlined in societal guidelines.

Ambiguity exists regarding the definition of a level III inferior vena cava tumor thrombus (IVC-TT), limiting comparisons between open and minimally-invasive series. We assessed 253 patients who underwent radical nephrectomy with IVC-TT from 2000-2015 and proposed a modified classification based on associations between intraoperative IVC clamp position and need for cardiopulmonary bypass with complications, length of stay, and blood transfusions. Predictive ability of the modified system was not meaningfully improved (AUCs 0.59–0.58; 0.61–0.61; 0.72–0.72). Nevertheless, we advocate for standardization of the border of a level III thrombus at or above the major hepatic veins to facilitate meaningful comparisons between techniques.

4567 Background: Trials combining anti-PDL1 and anti-VEGF therapies for clear cell renal cell carcinoma (ccRCC) are underway; however the relationship between the expression of PDL1 and genes in the VEGF pathway is poorly understood. Using the Affymetrix platform, we observed an inverse association between the expression of PDL1 and key genes in the VEGF pathway. Herein, we validate this inverse association using an independent set of 100 primary ccRCC tumors. Methods: From our registry database we sampled 100 ccRCC tumors with varying PDL1 protein expression (0%-100%) determined by immunohistochemistry (IHC). We extracted RNA from FFPE slides and performed RT-PCR to quantify gene expression of PDL1, VEGF, VEGFR1, and VEGFR2. All genes were normalized to the POLR2a gene. We evaluated the association of PDL1 protein expression and VEGF gene expression using Spearman rank correlation. In addition, we employed a linear mixed effects model to compare the fold-change in expression of VEGF genes between PDL1 low (0-5%, n=68) and PDL1 high (>5%, n=32) tumors. Results: As expected, PDL1 protein expression positively correlates with PDL1 geneexpression (corr=0.42, p<0.001). Validating our array data, PDL1 protein expression inversely correlates with expression of key VEGF genes: VEGF (corr=-0.23, p=0.01), VEGFR1 (corr=-0.34, p<0.001), and VEGFR2 (corr=-0.23, p=0.01). In our dichotomized analysis, we noted significantly higher expression of VEGF genes in the PDL1 low compared to the PDL1 high group: VEGF (fold change=1.82, p<0.001), VEGFR1 (FC=2.63, p<0.001), and VEGFR2 (FC=2.13, p=0.001). Conclusions: We independently validate an inverse association between the expression of PDL1 and key genes in the VEGF pathway in primary ccRCC. If validated further in larger studies, the existence of an immune evasive and an angiogenic phenotype within ccRCC could inform current clinical trials targeting these two pathways. Ultimately, whether VEGF signaling affects PDL1 expression, or whether angiogenic or immune evasive phenotypes predict response to anti-PDL1, anti-VEGF, or a combination of the two therapies remains unclear.

TPS594 Background: The standard treatment for upper tract urothelial carcinoma (UTUC) is radical nephroureterectomy (RNU) with bladder cuff resection. Subsequent intravesical recurrence is common and results in patient morbidity and increased healthcare cost. Level 1 evidence has demonstrated reduction of intravesical recurrence with instillation of intravesical Mitomycin C at 10 days following RNU. However, there has been limited adoption of Mitomycin C due to concerns for toxicity and logistics of postoperative drug delivery. Meanwhile, immediate intravesical gemcitabine has been shown to reduce intravesical recurrence following transurethral resection of bladder cancers without increasing toxicity compared to placebo. Moreover, small series have suggested improved efficacy of intraoperative intravesical chemotherapy for RNU. The purpose of the GEMINI trial, therefore, is to prospectively establish the safety and efficacy of intraoperative instillation of intravesical gemcitabine in patients undergoing RNU for UTUC. Methods: GEMINI is a multi-center open-label, single-arm, Phase II study that aims to enroll 90 patients with cTa-T4N0M0 UTUC. Patients receive intraoperative intravesical instillation of gemcitabine at the beginning of RNU, to be held in the bladder for at least 1 hour. The instilled drug will be drained prior to resection of the bladder cuff. Patients will undergo standard of care postoperative surveillance, including cystoscopy at 3, 6, 12, 18, and 24 months. The primary endpoint is 1-year intravesical recurrence-free survival. The historical event rate for no treatment is 30%, and we estimated a 40% relative reduction in event rate with gemcitabine. The study is powered to provide 80% power to detect this difference based on a one-sided exact test of proportions with alpha level 0.05. Secondary endpoints include time to recurrence and stratification of recurrence free survival by tumor grade, tumor stage, neoadjuvant chemotherapy, ureteral tumor location, and history of bladder cancer. Safety and adverse event endpoints will be evaluated. Complete accrual is expected within 3 years.

725 Background: The impact of surgical resection of renal tumors on peripheral immune related cells is not well characterized, and has potential implications as biomarkers for systemic immune therapy are being developed. We sought to assess the effect of surgical resection on circulating cytotoxic T-cells (CTLs) for patients with renal tumors. Methods: We prospectively enrolled 40 patients undergoing partial, radical, or cytoreductive nephrectomy (PN, RN, CN) for unilateral primary renal tumors between 2016 and 2018. Blood draws were performed pre-op, 1 day post-op, and 3 months post-op. Flow cytometry was performed on peripheral blood mononuclear cells (PBMCs). The % of PBMCs expressing CD11a/CD8 (CTLs) were assessed. The % of CTLs expressing PD-1, Bim (a downstream PD-1 pathway pro-apoptotic mediator), CX3CR1/GZMB (an effector memory T-cell phenotype), and Ki67 (a proliferation marker) were assessed. Median changes in % of CTLs were evaluated with the Wilcoxon signed rank test. Comparisons between aggressive (pT3-4, N1, M1, or aggressive histology (high-grade, coagulative necrosis, sarcomatoid dedifferentiation, or specific RCC-variant histologies)) versus indolent tumors were assessed using the Wilcoxon rank sum test. Results: Twenty, 12, and 8 patients underwent RN, PN, and CN, respectively. Thirty, 7, and 3 patients had clear-cell RCC, non-clear cell RCC, and oncocytoma, respectively. Twenty-three and 17 patients had aggressive and indolent tumors, respectively. While there was no significant change at 1 day, by 3 months there were significantly increased CTLs among PBMCs (+1.3%; p=0.004). There was significant decrease in CX3CR1+GZMB+ CTLs (-2.9%; p<0.001) and significant increase in Bim+ CTLs (+3.0%; p=0.03) at 1 day but not 3 months. Interestingly, Ki67+ CTLs increased at day 1 (+0.6%; p<0.001) but decreased by 3 months (-0.6%; p=0.001). There were no significant changes in PD-1+ CTLs at either time point. There were no significant changes in any CTL characteristics at 1 day or 3 months between aggressive and indolent tumors. Conclusions: These findings characterize changing CTL profiles over time with surgical resection of renal tumors which may help guide biomarker development.