Molecular, immunologic, and clinicodemographic landscape of MYC-amplified (MYCamp) advanced prostate cancer (PCa)

5041

Background: The MYC oncogene is one of the most commonly amplified genes in PCa, contributes to androgen independent growth, and is potentially targetable. We sought to define the molecular, immunologic, and clinicodemographic landscape of MYCamp in advanced PCa to better understand progression and establish rationale for personalized treatments and combinations. Methods: Hybrid capture-based comprehensive genomic profiling (CGP) was performed on tumor samples from predominantly advanced PCa samples. MYCamp was defined as copy number (CN) ≥6. PD-L1 IHC was performed using Dako 22C3. A subset of patients (pts) with advanced PCa were selected from the Flatiron Health- Foundation Medicine (FM) clinicogenomic database (CGDB), a nationwide de-identified EHR-derived clinical DB linked to FM CGP data for pts treated from 01/2011-12/2020. The de-identified data originated from approximately 280 US cancer clinics (̃800 sites of care). Results: The genomic profiles of 12,528 tissue samples from unique PCa pts (including hormone sensitive and castrate resistant) were evaluated. MYCamp was detected in 10.6%, with a median MYC CN of 8. Median age was 67 years (67 for MYCwt versus 68 for MYCamp). MYCamp occurred at a higher frequency in men with African (N = 190/1,473, 12.9%) versus European (N = 996/9,796, 10.2%) ancestry (P = 0.002), was more frequent in metastatic biopsy sites vs primary (15.7% vs 6.2%, P < 0.001), and was most common in liver mets (20.2%). MYCamp CN > 15 was enriched for PD-L1 positivity (26.1%) compared with MYCwt (9.8%) or MYCamp CN 6-15 (11.5%) (CN > 15 vs wt P = 0.025). In pts with MYCamp vs MYCwt PCa AR, RAD21, PTEN, CCND1, ZNF703, FGF19, FGFR1, and FGF3 each had significantly higher rates of CN changes (all p < 0.001); TP53 mutation was also more common with MYCamp (47.5% vs 39.7%, P < 0.001). MYCamp tumors were less likely to harbor microsatellite instability vs MYCwt (0.8% vs 2.4%, P < 0.001) and had higher tumor mutational burden (median 2.6 vs 1.7 mut/Mb, P < 0.001). In liquid samples with evidence of circulating tumor DNA (compositive tumor fraction [cTF] > 0) from PCa pts MYCamp was detected in 2.0% (28/1,402), and in 4.5% (20/445) with cTF > 20%. Among evaluable PCa pts in the CGDB, (67 MYCamp and 658 MYCwt) MYCamp did not significantly impact treatment decisions, with the majority receiving novel hormone therapies (35.8% MYCamp vs. 31.5% MYCwt) or chemotherapy containing regimens (37.3% MYCamp vs. 27.7% MYCwt) as first therapy after CGP report. Conclusions: Herein, we report the largest analysis to date of molecular, immunologic, and clinicodemographic features of MYCamp advanced PCa. These findings suggest that MYCamp defines a biologically distinct subset of PCa pts for whom personalized combination treatments utilizing targeted and/or immunotherapies may be effective. Independent cohorts are needed to validate these findings.

Ancestral characterization of the genomic landscape, comprehensive genomic profiling utilization, and treatment patterns may inform disparities in advanced prostate cancer: A large-scale analysis

5003

Background: Prostate cancer (PCa) incidence, mortality, and outcomes vary widely across race/ethnicity. The underlying drivers of these differences are multifactorial, including systemic barriers that lead to wide variation in access to care including genomic and precision medicine. Men of African ancestry (AFR) are particularly underrepresented in genomic and precision medicine studies. Therefore, we sought to comprehensively assess patterns of gene alterations, comprehensive genomic profiling (CGP) utilization, and treatment patterns in a large, diverse advanced PCa cohort. Methods: 11,741 PCa patients with CGP, as part of routine clinical care (Foundation Medicine Inc., FMI) were evaluated for their genomic landscape. Predominant ancestry was inferred using a SNP-based approach (Connelly et al, AACR 2018). Independently, the US-based de-identified Flatiron Health (FH)-FMI clinico-genomic database (CGDB) of 897 evaluable PCa patients was also queried. Clinical characteristics and treatment selections were described for patients who received metastatic or castrate-resistant diagnosis between 1/2011 and 6/2020. Results: The FMI cohort included 1,422 (12%) men of AFR and 9,244 (79%) men of European ancestry (EUR). Median age was lower in AFR compared with EUR men (64 vs. 67, p < 0.001). TP53 and PTEN alterations and TMPRSS2-ERG rearrangements occurred less frequently in AFR than EUR men (35% vs. 43%, 21% vs. 33%, 15% vs. 33% respectively, p < 0.05). In contrast, alterations in SPOP (11.9% vs. 7.3%), CDK12 (10.0% vs. 5.2%), CCND1 (6.0% vs. 3.8%), KMT2D (7.7% vs. 5.1%), HGF (4.1% vs. 2.5%), and MYC (13.4% vs. 10.6%) were enriched in the AFR cohort (p < 0.05). Alteration frequency in BRCA1/2, AR, DNA damage response pathway genes, and actionable genes with therapy implications, were similar across ancestry. Of note, BRAF alterations were slightly enriched in AFR (5.0% vs. 3.2%, p < 0.05). In the CGDB cohort (79 AFR, 762 EUR), AFR men received a median of 2 lines of therapy prior to CGP, compared to 1 line for EUR men. Notably, the proportion of patients receiving immunotherapy and PARPi was similar across ancestry, however AFR men were less likely to receive clinical study drug compared with EUR men (11% vs 30%, p < 0.001), even among men with actionable alterations (1% vs 6%, p < 0.001). Conclusions: To our knowledge, this study encompasses the largest cohort, particularly of AFR men in a genomic study, that defines CGP utilization, the genomic landscape and therapeutic implications of CGP in PCa across ancestry. Overall, there were largely similar rates of actionable gene alterations across ancestry. Notably, AFR men were less likely to receive CGP earlier in their treatment course, and less likely to be treated on clinical trials, which could impact the genomic landscape, outcomes, and ultimately disparities.

Factors influencing noncompletion of radiotherapy among men with localized prostate cancer

199

Background: Treatment non-completion may occur with radiotherapy (RT), especially with protracted treatment courses such as RT for prostate cancer, and may affect the efficacy of RT. For men with localized prostate cancer managed with primary RT, we evaluated associations between rates of treatment non-completion and RT fractionation schedules. Methods: The National Cancer Database identified men diagnosed from 2004-2014 treated with primary RT. Patients receiving 180cGy/fraction (conventional), 200cGy/fraction (conventional), 250cGy/fraction (moderate hypofractionation), and 300cGy/fraction (moderate hypofractionation) were defined as having completed radiotherapy if they received ≥40 fractions, ≥37 fractions, ≥28 fractions, and ≥19 fractions, respectively. Stereotactic body radiotherapy (SBRT) was defined as 5-8 fractions of 600-800cGy/fraction. Odds ratios compared rates of treatment noncompletion, adjusting for various sociodemographic covariates. Propensity-adjusted multivariable Cox regression assessed the association between treatment completion and overall survival. Results: Of 93,079 patients, 90.5% (N = 84,260) received conventional fractionation, 2.3% (N = 2,181) received moderate hypofractionation, and 7.1% (N = 6,638) received SBRT. Rates of non-completion were 10.0% (N = 8,406) among patients who received conventional fractionation, 7.5% (N = 163) among patients who received moderate hypofractionation, and 1.7% (N = 115) among patients who received SBRT (OR versus conventional: 0.214, 95%CI 0.177-0.258, P < 0.001). The rate of non-completion among 15,417 African American patients was 11.8%, compared to 8.8% among 74,189 white patients (OR 1.39, 95%CI 1.31-1.47, P < 0.001). On subgroup analysis, the disparity in non-completion persisted for conventional fractionation (12.4% vs. 9.4%, OR 1.36, 95%CI 1.29-1.44, P < 0.001) and moderate hypofractionation (13.6% vs. 6.6%, OR 2.24, 95%CI 1.52-3.29, P < 0.001), but not for SBRT (2.0% vs. 1.6%, OR 1.25, 95%CI 0.76-2.06, P = 0.384). Non-completion was associated with worse survival on propensity-adjusted multivariate analysis (HR 1.37, 95%CI 1.31-1.43, P < 0.001). Conclusions: SBRT was associated with lower rates of RT non-completion among men with localized prostate cancer. African American race was associated with greater rates of treatment non-completion, although the disparity may be decreased among men receiving SBRT.

Association between travel distance and use of postoperative radiation therapy among men with organ-confined prostate cancer: Does geography influence treatment decisions?

24

Background: Following radical prostatectomy, men with adverse pathologic features or a persistent post-operative detectable PSA are candidates for postoperative radiation therapy (PORT). Previous data have suggested disparities in receipt of adjuvant radiation therapy for adverse pathologic features according to travel distance. Among patients without adverse pathologic features (pT2 disease and negative margins), the main indication for PORT is a persistent post-operative detectable PSA. However, it remains unknown whether the rate of receipt of PORT in this cohort of men with persistently detectable PSA is related to travel distance from the treating facility. Methods: Using the National Cancer Database, we identified 287,274 men with prostate cancer diagnosed in 2004-2015 managed with upfront surgery who were found to have pT2 disease with negative surgical margins. Multivariable logistic regression defined adjusted odds ratios (AORs) with 95% confidence intervals (95CI) of receiving PORT as the primary dependent variable and distance ( < 5, 5-10, 10-20, > 20 miles from the treatment facility) as the primary independent variable. Results: Within our cohort, progressively farther distance from the treatment facility was associated with lower rates of PORT. In patients living < 5 miles, 5-10 miles, 10-20 miles, and > 20 miles from the treating facility, rates of PORT were 1.52% (referent), 1.23% (AOR 0.86, 95CI 0.78-0.96), 1.11% (AOR 0.81, 95CI 0.73-0.90), and 0.65% (AOR 0.43, 95CI 0.38-0.47), respectively (p < 0.005 in pairwise comparisons). Conclusions: For men with localized prostate cancer without adverse pathologic features managed with surgery, increasing distance from treatment facility was associated with lower receipt of PORT. Given that the rate of a persistent post-operative detectable PSA is unlikely to depend on the distance to the treatment facility, these findings raise the possibility that the geographic availability of radiation treatment facilities influences the decision to undergo PORT for patients with persistent post-operative detectable PSA.

Identifying pan-cancer transcriptomic determinants of perineural and lymphovascular invasion using machine learning

3621

Background: Tumor invasion of nerves, blood vessels, and lymphatics are a primary means of local recurrence and escape from the local microenvironment, resulting in metastases and poor clinical outcomes. However, the genetic drivers that are most pertinent to these malignant processes are not well understood, and few therapeutics successfully target perineural invasion (PNI) and lympho-vascular invasion (LVI). Identifying genetic drivers and biomarkers can be valuable for therapeutic targeting and prognostication. Methods: We analyzed surgical pathology reports and bulk RNA-seq data of 1,624 patients across 12 cancer types from The Cancer Genome Atlas (TCGA). Differential gene expression analysis between patients with and without PNI/LVI was performed using DEseq2 in Python while adjusting for age, sex, race, and cancer type. Genes with an adjusted p-value < 0.001 were then used to derive parsimonious signatures using random forest classifier and recursive feature selection algorithms. Results: To assess whether these invasive histological phenotypes have clinical ramifications, we examined outcomes data and found that patients with PNI or LVI have reduced overall (OS) and disease-free survival (DFS) ( p < 0.05) relative to those without. In addition, patients with both PNI and LVI have the lowest DFS from our pan-cancer analysis, suggesting that each may have non-redundant contributions to poor outcomes. From the differential gene expression analysis, we identified a set of 621 and 606 genes that were highly associated with PNI and LVI, respectively (padj < 0.001). Many of these genes such as TEKT5 (padj = 3.18 x 10−64), which is canonically associated with ciliary and flagellar microtubules, and SCRIB (padj = 1.60 x 10−21), which helps establish apico-basal cell polarity, have not been described previously in relevance to PNI and LVI, and warrant further scientific and clinical investigation. These genes were ultimately condensed into a signature that optimizes for both model simplicity and goodness of fit with up to 90% accuracy as determined by trials on both a logistic regression and neural network model. Conclusions: We concluded from a pan-cancer analysis that PNI and LVI are associated with poor outcomes, and we were able to robustly identify sets of genes that characterize each invasive mechanism for further functional investigation.

Mental distress and mental health services receipt in foreign-born survivors of cancer: A national health interview survey analysis

e19001

Background: There is a greater burden of mental illness, in survivors of cancer compared with the general population. Though mental health interventions may reduce mental distress and improve subsequent oncological outcomes, there are disparities in mental health service (MHS) receipt in immigrant populations. Therefore, we examined contemporary patterns of mental distress and mental health service receipt by immigrant status in cancer survivors in the United States. Methods: Data are collected in non-institutionalized civilian adults by the US National Health Interview Survey. For this study, harmonized data of participants reporting a cancer diagnosis were extracted from the Integrated Health Interview Series from 2009-2018. Sample weight-adjusted estimates of mental distress were defined by the validated Kessler 6 (K6). MHS receipt in the past 12 months was estimated, stratified by K6 status. Multivariable logistic regression defined adjusted odds ratios (AOR) and 95% confidence intervals (95CI) for the odds of MHS receipt, with birth status (US vs. non-US) as the primary independent variable of interest. Results: Among 14,653 adult survivors of cancer and 207,018 adults without cancer, 4.16% vs. 3.01% had K6 >13, respectively (AOR 0.96, 95CI 0.87-1.07, P = 0.504). Among survivors of cancer, younger age, female sex, and white race were associated with K6>13, while factors associated with lower MHS receipt included non-US born status, non-white race, and older age. The distribution of severe mental illness (K6>13) did not differ by place of birth. However, non-US birth status was associated with lower MHS receipt among survivors of cancer with K6 < 13 (5.61% vs 8.15%, AOR 0.67, 95CI 0.49-0.92, P = 0.013), and there was a greater disparity among those with K6>13 (9.43% vs 37.8%, AOR 0.19, 95CI 0.08-0.45, P < 0.001) (Pinteraction= 0.002). Conclusions: In this large contemporary cross-sectional survey, though there was a similar distribution of mental distress in survivors of cancer based on birth status, non-US born adults with severe mental distress (K613) were 81% less likely to receive MHS relative to US born adults. These data suggest that immigrant survivors of cancer who suffer from severe mental distress may be a greater risk not receiving appropriate MHS, which could lead to subsequent adverse outcome. Given the demonstrated gap in use of MHS in non-US born adults with cancer and severe mental distress, increased efforts are needed to screen for mental illness and the need for MHS in immigrant populations.

Characteristics of radiation-associated bladder cancer compared to primary bladder cancer

582

Background: Radiation-associated muscle-invasive bladder cancer (RA-MIBC) has been suggested to represent a more aggressive disease variant compared to primary (non-radiation associated) MIBC. We sought to characterize the presentation, patterns of care, and outcomes of RA-MIBC compared to primary MIBC. Methods: We identified 60,117 patients diagnosed with non-metastatic or metastatic MIBC between 1988 and 2015 using the Surveillance, Epidemiology, and End Results (SEER) database and stratified patients based on whether radiation had been administered to a pelvic primary prior to the development of bladder cancer. We used logistic regression to compare rates of chemotherapy, surgery, or radiation for patients with RA-MIBC compared to primary MIBC. We used Fine-Gray competing risks regression to compare adjusted bladder cancer-specific mortality (BCSM) for RA-MIBC and primary MIBC. Results: There were 1,093 patients with RA-MIBC and 59,024 patients with primary MIBC. Patients with RA-MIBC were older compared to patients with primary MIBC (mean age 77.4 years vs 72.4 years, p < 0.001) and more likely to be male (86.8% vs 73.3%, p<0.001). RA-MIBCs were more likely to be high-grade (57.5% vs 47.6%, p<0.001), more likely to have T4 disease at diagnosis (21.0% vs 17.3%, p<0.001), and less likely to be node-positive (4.2% vs 8.1%, p < 0.001). In terms of treatment, non-metastatic primary MIBC patients were more likely to undergo radiation (14.0% vs 3.1%, p<0.001) as well as radiation with cystectomy (1.9% vs 0.8%, p<0.001) compared to those with RA-MIBC. Median survival was significantly shorter for patients with RA-MIBC (13 mo. vs 19 mo.; p<0.001). Conclusions: RA-MIBCs tend to present with higher grade and higher stage disease and are less likely to receive curative treatment. Even when adjusting for stage, grade, and receipt of treatment, patients with RA-MIBC have worse survival compared to those with primary MIBC. These findings raise the possibility that RA-MIBC represents a biologically more aggressive disease compared to primary MIBC. Future research is needed to better understand biological differences between RA-MIBC and primary MIBC and develop improved therapeutics for radiation-associated cancers.

Differential expression of PSMA and 18F-fluciclovine transporter genes in metastatic castrate-resistant and treatment-emergent small cell/neuroendocrine prostate cancer

24

Background: 18F-fluciclovine (Axumin) PET/CT imaging is recommended by the NCCN in the setting of biochemical recurrence, while prostate-specific membrane antigen (PSMA) PET/CT is preferred by the EAU. The utility of these methods in the post-androgen deprivation therapy (ADT) setting however, is less defined. Our objective was to compare relative gene expression of the molecular targets of these imaging modalities— fluciclovine transporter genes (LAT1-4, ASCT1-2) and PSMA—in metastatic castrate resistant prostate cancer (mCRPC) and treatment-emergent small cell/neuroendocrine prostate cancer (t-SCNC). Methods: Genome-wide expression profiles of five mCRPC cohorts (Aggarwal, Grasso, Kumar, Beltran, Robinson, et al) were used to characterize relative expression of fluciclovine transporter (LAT1-4, ASC1-2) and PSMA (FOLH1) genes. 3 cohorts (Kumar, Beltran, Aggarwal) were enriched with t-SCNC tumors. The GSE35988 cohort included primary tumors and mCRPC. RNA expression profiling methods were consistent within cohorts. Results: 518 mCRPC specimens were included. In the GSE35988 cohort, PSMA expression was downregulated in mCRPC when compared to primary localized tumors (p=0.01). PSMA expression was further depressed in t-SCNC when compared with mCRPC (p<0.001). Of the fluciclovine transporter genes, LAT1 and LAT4 were overexpressed in mCRPC when compared to primary tumors, while ASC2 was less expressed (p<0.001). LAT1 was further overexpressed in t-SCNC when compared to mCRPC, while LAT2 was less expressed (p<0.001). PSMA expression was negatively correlated with LAT1 (p<0.001) but positively correlated with LAT2 (p=0.006). Other fluciclovine transporters were not correlated. Conclusions: Expression of PSMA and a subset of fluciclovine transporter genes are inversely correlated in mCRPC and t-SCNC. These findings suggest that fluciclovine-based imaging may play a role in castrate resistant states. Clinical comparison between PSMA- and fluciclovine-based imaging modalities in mCRPC and t-SCNC is warranted.

Prostate-directed radiation therapy and overall survival for men with M1a prostate cancer

101

Background: A recent randomized controlled trial demonstrated that radiation therapy to the prostate improves overall survival for men with newly diagnosed metastatic prostate cancer with a low metastatic burden. Most patients in this trial had bony metastases (stage M1b). The benefit of prostate-directed radiation therapy for men with metastases limited to non-regional lymph nodes (stage M1a) is unknown. We investigated the association between prostate-directed radiation therapy and overall survival for men with M1a prostate cancer. Methods: We identified 2,079 men from the National Cancer Database who were newly diagnosed with M1a prostate adenocarcinoma from 2004 through 2014 and had data on the use of androgen deprivation therapy, chemotherapy, and radiation therapy. Median follow-up was estimated using the reverse Kaplan-Meier method. The association between radiation therapy to the prostate and overall survival was examined using multivariable Cox proportional hazards regression analysis. Results: Overall, 12.7% (264) of patients received radiation therapy to the prostate. Median follow-up was 4.6 years (95% confidence interval 4.3-4.8 years). On multivariable analysis, when accounting for the use of androgen deprivation therapy and chemotherapy, Gleason grade group, clinical tumor and nodal stage, and prostate-specific antigen level at diagnosis, the use of radiation therapy to the prostate was associated with a significant improvement in overall survival (adjusted hazard ratio 0.60, 95% confidence interval 0.49-0.74, P<0.001). Adjusted median overall survival was 3.3 years for patients who did not receive radiation therapy to the prostate compared to 5.5 years for patients who did. Conclusions: Similar to newly diagnosed M1b prostate cancer with a low metastatic burden, patients with M1a prostate cancer may also derive a significant overall survival benefit from receiving radiation therapy to the primary prostate tumor. The use of prostate-directed radiation therapy for M1a patients should be further investigated.

Characterization of PSMA and 18F-fluciclovine transporter gene expression in localized prostate cancer

295

Background: While 18F-fluciclovine PET/CT is approved in the US and recommended by the NCCN, prostate-specific membrane antigen (PSMA) PET/CT is more common in Europe/Australia and recommended by the EAU. Less is known about the biology of lesions detected by either modality. 18F-fluciclovine PET relies on radiotracer uptake by amino acid transporters LAT1-4 and ASCT1-2. PSMA PET is dependent on surface expression of PSMA. We compared relative expression of PSMA and fluciclovine transporter genes in radical prostatectomy (RP) samples to determine their distribution across subtypes and correlation with outcomes. Methods: Gene expression data of 19,102 RP samples were analyzed using the Affymetrix Human Exon 1.0 ST microarray. 1,135 patients had long term follow up. Associations between expression of PSMA and fluciclovine transporter genes (LAT1-4 and ASCT1-2) and pathologic variables, molecular subtypes, and clinical outcomes were conducted. Results: All fluciclovine transporter genes (LAT 1-4, ASCT1-2) were expressed at lower levels than PSMA (p <0.0001). PSMA expression was positively correlated with genomic risk score and pathologic Gleason score (p<0.0001), but LAT2-3 and ASCT2 were inversely correlated with genomic risk in primary tumors (p<0.0001) and less expressed in GS 9-10 tumors (p<0.0001). PSMA expression was associated with worse metastasis-free survival (MFS) (HR 1.45, p=0.001) and lymph node involvement (HR 2.14, p<0.0001). Expression of LAT2, LAT3, ASCT2 expression was associated with better MFS (HR 0.85, 0.63, 0.74, p<0.0001-0.04). After multivariable adjustment, PSMA expression remained independently prognostic of poorer MFS (HR 1.3, p=0.028). Luminal B subtype was notable for PSMA overexpression; Luminal A was enriched in ASCT2 and LAT2 (p<0.0001). PSMA expression did not correlate with ERG fusion prostate cancers, but LAT2, ASCT1, and ASCT2 were overexpressed in ERG fusion negative tumors (p<0.0001). Conclusions: PSMA expression is associated with more aggressive disease and poorer clinical outcomes than fluciclovine transporter genes in localized prostate cancer. Molecular subtypes of prostate cancer vary in PSMA and fluciclovine transporter gene expression.

Association of black race with improved outcomes following definitive radiotherapy with androgen deprivation therapy for high-risk prostate cancer: A meta-analysis of eight randomized trials

327

Background: Though Black men with prostate cancer are more likely to have aggressive disease features than White men, race-specific differences in initial treatment responses in localized disease remains unknown. Methods: Individual patient data were obtained for 9259 patients (including 1674 [18.1%] Black men and 7585 [81.9%] White men) enrolled on eight randomized controlled trials evaluating definitive radiotherapy (RT) ± short-term or long-term androgen deprivation therapy (STADT and LTADT). The primary endpoints were biochemical recurrence (BCR), distant metastasis (DM), and prostate cancer-specific mortality (PCSM). Fine-Gray subdistribution HR (sHR) models were developed to evaluate the cumulative incidences of all endpoints after stratification by National Comprehensive Cancer Network risk grouping. A meta-analysis was done to estimate pair-wise comparisons of treatments within and between Black and White men, after adjusting for age, Gleason score, clinical T stage, and initial PSA. Results: Black men were more likely to have NCCN high-risk disease at enrollment (656/1674 [39.2%] vs 2506/7585 [33%], p<0.001). However, within the high-risk stratum Black men had lower 10-year rates of BCR (46.1% vs. 50.4%, p=0.02), DM (14% vs. 21.6%, p<0.001), and PCSM (4.9% vs. 9.8%, p<0.001). After adjusting for age and disease characteristics, Black men with high-risk prostate receiving RT+STADT had lower rates of BCR (sHR 0.73, 95% CI 0.62-0.86, p<0.001), DM (sHR 0.64, 95% CI 0.49-0.84, p=0.001) and PCSM (sHR 0.49, 95% CI 0.25-0.95, p=0.04). There were no differences in BCR, DM, or PCSM among men receiving RT+LTADT. The interaction between race and the impact of adding STADT to RT alone on BCR was statistically significant (p=0.003). Conclusions: Black men enrolled on randomized trials with long-term follow-up have higher risk disease at enrollment, but have better BCR, DM, and PCSM outcomes with RT-based therapy compared with White men, particularly with the addition of STADT.

Doublecortin expression in prostate adenocarcinoma and neuroendocrine tumors

161

Background: Recent work using prostate cancer mouse models implicated doublecortin (DCX)-expressing neural progenitor cells in prostate adenocarcinoma, reporting a strong association between DCX expression and disease progression and outcome. We sought to evaluate the relationship between DCX expression and these outcomes in human prostate cancer. Methods: DCX expression was measured in transcriptome-wide microarray data from 18,501 patients with localized prostate cancer and 290 patients with metastatic castration-resistant prostate cancer (mCRPC). Pairwise comparisons were performed using the Mann–Whitney U test. Metastasis-free survival (MFS) and overall survival (OS) were analyzed using Cox-proportional hazards. Results: DCX expression was not significantly different between normal prostate (n=29), primary prostate cancer (n=131), or metastases (n=19) (p > 0.5), and did not differ across Gleason score in a large cohort of RP samples (n=17,967, p=0.21). The lack of difference persisted after adjusting for stromal contribution using a 141-gene stromal signature. Those with DCX expression above and below the median did not have significant differences in MFS (HR 1.2 [0.84-1.7], p=0.3) or OS (HR 1.15 [0.7-1.84], p =0.56). In a cohort of untreated prostate cancer, DCX expression was higher in neuroendocrine tumors (n=10) compared to Gleason 9-10 prostate adenocarcinoma (n=110) (p=0.007). Similarly, in two cohorts with mCRPC (n=290), DCX expression was higher in lesions with neuroendocrine features than adenocarcinoma (p<0.001). Consistently, in a patient-derived xenograft model subjected to host castration, DCX expression was initially low, but increased significantly once tumors underwent neuroendocrine differentiation and treatment escape. Conclusions: Contrary to recent data using mouse models, DCX expression did not differ by disease state, grade, or outcome in a dataset of human patients with prostate adenocarcinoma. However, DCX expression appeared to correlate with neuroendocrine prostate cancers, a subgroup that can arise de novo or in the castrate-resistant setting. Further work is needed to define the role of DCX expression and its prognostic significance in prostate cancer.

Surgical management versus combination radiotherapy in Gleason score 9-10 prostate cancer

135

Background: For men with Gleason score 9-10 prostate cancer, studies have demonstrated conflicting results on the outcomes from combination radiation therapy (ComboRT) with external beam radiation therapy plus brachytherapy boost versus radical prostatectomy (RP), with or without adjuvant radiation therapy (ART). Differences in patient selection and management may explain some of the disparate outcomes of prior reports. Methods: The Surveillance, Epidemiology, and End Results database identified 10,396 men managed with ComboRT versus RP (+/-ART). Competing-risks regression analysis with treatment propensity adjustment defined hazard ratios (aHR) for prostate cancer-specific mortality (PCSM), controlling for patient-specific demographic factors. To explore the possible effect of patient selection, analyses were conducted before and after excluding men from analysis if they had evidence-based indications for ART (adverse pathology, i.e. pT3-T4 or positive margins) but did not receive it. Results: Median age was 64 years; median follow-up was 69 months. Five-year PCSM was similar between patients treated with RP (with or without ART, regardless of pathologic features, N=8,934) and ComboRT (N=1,462) (6.9% vs 8.1%, aHR=0.94, 95% confidence interval [CI] 0.78–1.13, P=0.51). After excluding RP-treated men with adverse pathology who did not receive ART (N=4,527 excluded), patients treated with RP+/-ART (N=4,407) had improved 5-year PCSM compared with those treated with ComboRT (5.3% vs 8.1%, aHR=0.74, 95% CI 0.60–0.91, P=0.004). Conclusions: For Gleason 9-10 prostate cancer, ComboRT was associated with similar PCSM compared to RP, but risk-tailored surgical management may be associated with superior PCSM.

Rates and patterns of uninsured cancer survivors before and after implementation of the Affordable Care Act, 2000-2017

e18105

Background: Cancer survivors experience difficulties in maintaining healthcare coverage, however the reasons and risk factors for lack of insurance are poorly defined. We sought to assess self-reported reasons for not having insurance and to assess demographic and socioeconomic factors associated with non-insurance among cancer survivors, before and after implementation of the Affordable Care Act (ACA) in 2014. Methods: We used the National Health Interview Survey to identify adult participants (18-64 years) reporting a cancer diagnosis between 2000-2017. Multivariable logistic regression was used to define the association between demographic and socioeconomic variables and odds being uninsured. The prevalence of the most common self-reported reasons for not having insurance (unemployment, employment-related reason, family-related) were estimated, with AORs for each of the reasons defined by multivariable logistic regression. Results: Among 17,806 survey participants, 10.3% reported not having health insurance. Individuals surveyed in 2000-2013 had higher odds of not having insurance as compared to those surveyed in 2014-2017 (10.6% vs. 6.2%, AOR 1.75, 95% CI 1.49-2.08). Variables associated with higher odds of non-insurance throughout the entire study interval included younger age, annual family income below the poverty threshold, black race, Hispanic ethnicity, non-citizen status and current smoking (p < 0.001 for all). After implementation of the ACA, increasing interval from cancer diagnosis and black race were no longer associated with not having insurance. The most commonly cited reason for not having insurance were cost followed by unemployment, both of which decreased after ACA implementation (cost: 49.6% vs. 37.6%, AOR 0.62, 95% CI 0.46-0.85; unemployment: 37.1% vs. 28.5%, AOR 0.62, 95% CI 0.45-0.87). Conclusions: The proportion of uninsured cancer survivors decreased after implementation of the ACA, however certain subgroups remain at greater risk of being uninsured. Cost remains the primary barrier to obtaining insurance, although more than half of cancer survivors reported other barriers to coverage. Given the growing number of cancer survivors in conjunction with rising health costs, efforts addressing barriers to insurance coverage are needed for this population.

The impact of race and socioeconomic status on outcomes for HPV-associated squamous cell carcinoma of the head and neck

e18103

Background: The socioeconomic factors affecting outcomes of human papillomavirus (HPV)-associated squamous cell carcinoma of the head and neck (SCCHN) are poorly characterized. Methods: A custom Surveillance, Epidemiology, and End Results (SEER) database identified adult patients with primary non-metastatic SCCHN and known HPV status diagnosed between 2013-14. Multivariable logistic regression defined associations between patient characteristics and HPV status, with adjusted odds ratios (AORs) and 95% confidence intervals (CIs) reported. Fine-Gray competing risks regression estimated adjusted hazard ratios (AHRs) and 95% CIs for cancer-specific mortality (CSM), including a disease subsite*HPV status*race interaction term. Results: 4735 patients with non-metastatic SCCHN and known HPV status were identified. HPV-associated SCCHN was positively associated with oropharyngeal primary, male sex and higher education and negatively associated with uninsured status, single marital status, and non-white race (p≤0.001 for all). For HPV-positive oropharyngeal SCCHN, white race was associated with lower CSM (AHR 0.55, 95%CI 0.34-0.88, p = 0.01) and uninsured status was associated with higher CSM (AHR 3.12, 95%CI 1.19-8.13, p = 0.02). These associations were not observed in HPV-negative or non-oropharynx SCCHN. Accordingly, there was a statistically significant disease subsite*HPV status*race interaction (pint< 0.001). Conclusions: Non-white race and uninsured status were associated with worse CSM in HPV-positive oropharyngeal SCCHN, while no such associations were observed in HPV-negative or non-oropharyngeal SCCHN. These results suggest that, despite having clinically favorable disease, non-white patients with HPV-positive oropharyngeal SCCHN have worse outcomes than their white peers. Further work is needed to understand and reduce socioeconomic disparities in SCCHN.

“Management Migration” in United States patients diagnosed with localized prostate cancer from 2010-2015

11

Background: National guidelines have increasingly supported active surveillance/watchful waiting (AS/WW) in low- and favorable intermediate-risk prostate cancer (PCa). It is unknown how these changes have influenced national management patterns across localized PCa. Therefore, we sought to define the U.S. trends in management of localized PCa across National Comprehensive Cancer Network (NCCN) risk groups. Methods: Using the novel and non-public Surveillance, Epidemiology, and End Results Program Prostate with AS/WW Database, we identified 164,760 men diagnosed with localized PCa and actively treated with either AS/WW, radical prostatectomy [RP], or radiation therapy [RT] from 2010-2015. Rates of initial management type over time, stratified by NCCN risk-category, were determined. Multivariable logistic regression defined adjusted odds ratios (AORs) and 95% confidence intervals (CI) for receipt of each initial management type, with year of diagnosis (2010-2015) as the independent variable of interest (Year 2010 = referent). Results: AS/WW utilization increased from 14.5% to 42.1% from 2010-2015 in low-risk disease (AOR 4.50 [95% CI 4.17–4.86, P < 0.001]); conversely, RT and RP decreased from 38.0% to 26.6% (AOR 0.55 [0.51–0.59, P < 0.001]), and from 47.4% to 31.3% (AOR 0.50, [0.47-0.54, P < 0.001]), respectively (all Ptrends< 0.001). AS/WW increased in intermediate-risk disease from 5.78% to 9.60% (AOR 1.83 [1.67–2.00, P < 0.001]) and RT also decreased from 42.4% to 39.8% (AOR 0.81 [0.77–0.85], P < 0.001; Ptrends< 0.001)—Yet, there was no change in RP (51.8% vs. 50.6%; AOR 1.03 [0.98–1.09, P = 0.254]). Notably, while RP for high-risk disease increased from 38.0% to 42.8% (AOR 1.41 [1.30–1.53, P < 0.001]), RT decreased from 60.1% to 55.0% (AOR 0.71 [0.65–0.77, P < 0.001]; Ptrends< 0.001). Conclusions: These findings capture the rapidly shifting landscape of management for localized PCa and are suggestive of “management migration”—where down-trending RP utilization in low-risk disease (in the setting of up-trending AS/WW) may drive non-evidence based management bias toward RP over RT in higher risk disease. These national patterns serve as a targetable trend that should be addressed.

Active surveillance and watchful waiting for low-risk prostate cancer in black patients: A population-based analysis

10

Background: Evidence from clinical trials supports conservative management as an acceptable alternative to definitive therapy for low-risk prostate cancer (LRPC). The optimal approach for Black men, however, remains unclear given trial underrepresentation and concern about racial differences in disease aggressiveness. We therefore sought to determine U.S. conservative management utilization rates for Black men with LRPC. Methods: The Surveillance, Epidemiology, and End Results (SEER) Program Prostate with Active Surveillance/Watchful Waiting (AS/WW) Database queried 50,302 LRPC patients (N = 5218 Black), diagnosed from 2010-2015. Trends in AS/WW utilization over time were determined, stratified by race (Black versus non-Black) and number of positive biopsy cores (≤2 versus ≥3). Results: From 2010 to 2015, AS/WW utilization increased from 12.6% to 36.4% among Black men (Ptrend< 0.001) and from 14.8% to 43.3% among non-Black men (Ptrend< 0.001). AS/WW rates reached 52.0% and 57.3% by 2015 for Black (Ptrend< 0.001) and non-Black (Ptrend< 0.001) men with ≤2 positive biopsy cores, respectively. Rates continually increased for all subgroups except Black men with ≥3 positive biopsy cores, where rates plateaued at 22.9% by 2013. Conclusions: In this report from the largest U.S. population of Black LRPC patients with quality assured AS/WW data, AS/WW rates have nearly tripled for Black men from 2010-2015, suggesting AS/WW is viewed as a safe management option in all races.

Conservative management of low-risk prostate cancer among young versus older men in the United States: Trends and outcomes from a novel national database

12

Background: The optimal management for men age ≤55 with low-risk prostate cancer (PCa) is debated given quality of life implications with definitive treatment versus potential missed opportunity for cure with conservative management. We sought to define rates of conservative management for low-risk PCa and associated short-term outcomes in young versus older men in the United States (U.S.). Methods: The Surveillance, Epidemiology, and End Results (SEER) Prostate with Active Surveillance/Watchful Waiting (AS/WW) Database identified 50,302 men diagnosed with low-risk PCa from 2010-2015. AS/WW rates in the U.S. were stratified by age (≤55 versus ≥56). Prostate cancer-specific mortality (PCSM)and overall mortality were defined by initial management type (AS/WW versus definitive treatment [referent]) and age. This non-public data was released by the SEER custom data group. Results: AS/WW utilization increased from 8.61% in 2010 to 34.56% in 2015 among men age ≤55 (Ptrend< 0.001) and from 15.99% to 43.81% among men age ≥56 (Ptrend< 0.001). Among patients with ≤2 positive biopsy cores, AS/WW rates increased from 12.90% to 48.78% for men age ≤55 and from 21.85% to 58.01% for men age ≥56. Among patients with ≥3 positive biopsy cores, AS/WW rates increased from 3.89% to 22.45% for men age ≤55 and from 10.05% to 28.49% for men age ≥56 (all Ptrend< 0.001). Five-year PCSM rates were below 0.30% across age and initial management type subgroups. Conclusions: AS/WW rates quadrupled for patients age ≤55 from 2010-2015, with favorable short-term outcomes. These findings demonstrate the short-term safety and increasing acceptance of AS/WW for both younger and older patients. However, there are still higher absolute rates of AS/WW in older patients (P < 0.001), suggesting some national ambivalence toward AS/WW in younger patients.

External beam radiation therapy and brachytherapy boost versus radical prostatectomy and adjuvant radiation therapy for high-risk prostate cancer

21

Background: Previous studies have suggested that combination external beam radiation therapy (EBRT) with brachytherapy boost (BT) for high-risk prostate cancer is associated with equivalent overall survival (OS) compared with radical prostatectomy (RP). However, it is not known whether RP with post-operative radiation therapy (PORT) can offer improved OS compared with combination RT (EBRT + BT + androgen deprivation therapy [ADT]) for patients with Gleason 9-10 high-risk disease. Methods: We identified all patients diagnosed with clinical T1-T3, Gleason 9-10, prostate-specific antigen (PSA) 0-40 ng/mL, and clinically node negative disease between 2004 and 2014 from the National Cancer Database. We divided patients into 4 treatment groups: EBRT + ADT, combination RT (EBRT + BT + ADT), RP, and RP + PORT. Only patients who received PORT within 360 days of surgery were included within the RP + PORT group. We compared OS utilizing inverse probability of treatment-weighted multivariable Cox proportional hazards regression modeling after accounting for clinical and demographic factors, including Gleason grade (9 versus 10), T-stage (T1, T2, T3), age, Charlson-Deyo comorbidity score (0, 1, versus 2), education quartile, income quartile, geographic location within the US, insurance status, facility volume, and race. Results: Median follow-up in the entire cohort was 4.5 years. The numbers of patients treated with EBRT + ADT, EBRT + BT + ADT, RP, RP + PORT were 6778, 924, 7111, and 1929, respectively. There were no significant differences in 5-year OS when comparing combination RT to RP (85.0% vs 85.7%, adjusted hazard ratio (AHR) 0.92, 95% confidence interval [CI] 0.77-1.10, p = 0.36) or RP + PORT (85.0% vs 85.6%, AHR 0.89, 95% CI 0.71-1.12, p = 0.34). Combination RT was associated with superior 5-year OS compared to EBRT + ADT alone (without BT boost) (85.0% vs 79.4%, AHR 1.26, 95% CI 1.07-1.48, p < 0.01). Conclusions: Our study suggests that for patients with Gleason 9-10 tumors, multi-modality surgical therapy is equivalent to combination RT.

Patterns of care and outcomes of definitive external beam radiotherapy and radioembolization for localized hepatocellular carcinoma: A propensity score-adjusted analysis

329

Background: Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality worldwide. Most patients with localized HCC are not surgically operable or transplantation candidates, thus there is an increasing role for nonsurgical locoregional therapies. Ablative external beam radiotherapy (XRT) and transarterial radioembolization (TARE) are two emerging radiotherapeutic treatments for localized HCC. However, there are little data comparing their efficacy. We therefore sought to evaluate their utilization and efficacy in a large nationwide cohort. Methods: We conducted an observational study of 2,685 patients from the National Cancer Database diagnosed with American Joint Committee on Cancer 7th edition clinical stage I-III HCC between 2004-2015, treated with definitive-intent XRT delivered in 1-15 fractions or TARE. The association between treatment modality (XRT versus TARE [referent]) and overall survival (OS) was defined using propensity score-weighted Kaplan-Meier estimators and propensity score-weighted multivariable Cox regressions. Results: Among 2,685 patients, 2,007 (74.7%) received TARE and 678 (25.3%) received XRT, with increasing usage for both from 2004-2015 ( Ptrend < 0.001), but with overall greater uptake and absolute usage of TARE. Patients who received TARE were more likely to have elevated alpha fetoprotein and more advanced stage ( P < 0.05 for all). Median OS was 14.5 months for the entire cohort. XRT was associated with an OS advantage compared to TARE on propensity score-unadjusted analysis (adjusted hazard ratio [AHR] 0.80, 95% CI 0.67-0.95, P = 0.013), but not on propensity score-adjusted analysis (AHR 0.93, 95% CI 0.76-1.14, P = 0.491). Conclusions: Our study demonstrates that while both XRT and TARE usage have increased with time, there was greater uptake and absolute use of TARE, especially in advanced disease. Nevertheless, we found no difference in survival between XRT and TARE after propensity score-adjustment. Given their equivalence on retrospective study, prospective trials are necessary.

Impact of percent positive biopsy cores on cancer-specific mortality for patients with high-risk prostate cancer

78

Background: A high percent positive biopsy cores (PBC), typically dichotomized at ≥50%, is prognostic of worse cancer-specific outcomes for patients with low- and intermediate-risk prostate cancer. The prognostic value of ≥50% PBC for patients with high-risk disease is poorly understood. We examined the association between ≥50% PBC and prostate cancer-specific mortality (PCSM) for patients with high-risk prostate cancer. Methods: We identified 7,569 men from the Surveillance, Epidemiology, and End Results program who were diagnosed with high-risk prostate cancer (Gleason 8-10, prostate-specific antigen > 20 ng/mL, or cT3-T4 stage without evidence of nodal or metastatic disease) in 2010 or 2011 and had 6-24 cores sampled at biopsy. Multivariable Fine and Gray competing risks regression was utilized to examine the association between ≥50% PBC and PCSM, with adjustments for sociodemographic and clinicopathologic factors. Results: Median follow-up was 3.8 years (interquartile range 3.3-4.3 years). 56.2% of patients (4,253) had ≥50% PBC. The 4-year unadjusted cumulative incidences of PCSM were 2.0% (95% confidence interval [CI] 1.5-2.6%) and 5.6% (95% CI 4.9-6.4%) for patients with < 50% and ≥50% PBC, respectively. On multivariable analysis, the presence of ≥50% PBC was associated with a significantly higher risk of PCSM (adjusted hazard ratio [AHR] 1.95, 95% CI 1.43-2.66, P< 0.001). On subgroup analysis, ≥50% PBC was associated with a significantly higher risk of PCSM only for cT1-T2 disease (AHR 2.21, 95% CI 1.59-3.07, P< 0.001) but not cT3-T4 disease (AHR 0.77, 95% CI 0.33-1.81, P= 0.547), with a significant interaction ( Pinteraction= 0.012). Conclusions: In this large, contemporary cohort of patients with high-risk prostate cancer, ≥50% PBC was independently associated with a two-fold increased risk of PCSM for patients with cT1-T2, but not cT3-T4, tumors. Percent PBC should be used to routinely risk stratify men with high-risk disease and identify patients who may benefit from intensification of therapy, such as adding docetaxel or abiraterone to radiotherapy with androgen deprivation therapy, to optimize cancer-specific outcomes.

Clinical and genomic characterization of low-prostate-specific antigen, high-grade prostate cancer

59

Background: The consequences of a low prostate-specific antigen (PSA) in high-grade (Gleason 8-10) prostate cancer are unknown. We sought to evaluate the clinical implications and genomic features of this entity. Methods: Clinical and transcriptomic data from 626,057 patients with N0M0 prostate cancer were collected from two national cohorts and a large transcriptome database. Multivariable Fine-Gray and Cox regressions analyzed prostate-cancer specific mortality (PCSM) and all-cause mortality, respectively. GRID data were used to analyze transcriptomic features. Results: For Gleason 8-10 disease, the distribution of PCSM was U-shaped by PSA (PSA 4.1-10.0 ng/mL = referent), with adjusted hazard ratio (AHR) 2.70 for PSA ≤2.5 ng/mL (P < 0.001) versus 1.97, 1.36, and 2.56 for PSA 2.6-4.0, 10.1-20.0, and > 20.0 ng/mL, respectively. In contrast, distribution of PCSM by PSA was linear for Gleason ≤7 with AHR 0.41 for PSA ≤2.5 ng/mL (P = 0.127) versus 1.38, 2.28, and 4.61 for PSA 2.6-4.0, 10.1-20.0, and > 20.0 ng/mL, respectively (PGleason*PSA interaction< 0.001). Gleason 8-10, PSA ≤2.5 ng/mL disease had a significantly higher PCSM than standard high and very high-risk disease with PSA > 2.5 ng/mL (AHR 2.15, P = 0.009; 47-month PCSM 13.8% versus 4.9%). Among Gleason 8-10 patients treated with definitive radiotherapy, androgen deprivation therapy (ADT) was associated with a survival benefit for PSA > 2.5 ng/mL (AHR 0.87, P < 0.001) but not for ≤2.5ng/mL (AHR 1.36, P = 0.084; PADT*PSA interaction= 0.021). For Gleason 8-10 tumors, PSA ≤2.5 ng/mL was associated with a higher expression of neuroendocrine markers compared to > 2.5 ng/mL (P = 0.046), with no such relationship for Gleason ≤7. Conclusions: Low-PSA, high-grade prostate cancer appears to be a unique entity that has a very high risk for PCSM, potentially responds poorly to ADT, and is associated with neuroendocrine genomic features.

Androgen deprivation therapy and overall survival for Gleason 8 versus Gleason 9-10 prostate cancer

23

Background: While the addition of androgen deprivation therapy (ADT) to external beam radiotherapy is known to improve overall survival in Gleason 8-10 prostate cancer, it has been hypothesized that Gleason 9-10 disease, which is less differentiated than Gleason 8 disease, may be less sensitive to ADT. To investigate this idea, we examined the association between ADT and overall survival for Gleason 8 versus Gleason 9-10 prostate cancer. Methods: We identified 20,139 men in the National Cancer Database diagnosed with localized or locally advanced, Gleason 8-10 prostate cancer from 2004 through 2011 who received external beam radiotherapy. Patients with clinical evidence of nodal or metastatic disease were excluded. Cox proportional hazards regression was used to examine the association between ADT and overall survival. Results: Median follow-up was 4.0 years. 78.2% (9,509) of the 12,160 men with Gleason 8 disease and 86.6% (6,908) of the 7,979 men with Gleason 9-10 disease received ADT. On multivariable analysis, ADT was associated with a significant improvement in overall survival for Gleason 8 patients (adjusted hazard ratio 0.79, 95% confidence interval 0.71-0.88, P< 0.001) but not Gleason 9-10 patients (adjusted hazard ratio 0.96, 95% confidence interval 0.83-1.10, P= 0.532), with a significant interaction ( Pinteraction= 0.020). When considering Gleason 9-10 patients separately as Gleason 9 and Gleason 10, a higher Gleason score correlated with an increased adjusted hazard ratio for the association between ADT and overall survival ( Pinteraction= 0.012). Conclusions: In contrast to the significant survival advantage of ADT for Gleason 8 disease, our results strongly suggest that Gleason 9-10 disease may be less sensitive to ADT and that a higher Gleason score predicts lesser sensitivity. Consideration should be given to treatment intensification for Gleason 9-10 patients through enrollment in clinical trials or potentially adding novel antiandrogens or docetaxel, which have shown efficacy in both castration-resistant and castration-sensitive settings.

Laboratory eligibility criteria as potential barriers to participation by black men in prostate cancer clinical trials

73

Background: Eligibility criteria may disproportionately affect black patients and contribute to their underrepresentation in clinical trials. We studied this potential barrier by examining clinical trials in prostate cancer, a disease in which black men face higher incidence and mortality. Specifically, we investigated the use of serum creatinine (sCr) alone instead of race-adjusted measurements for renal function, and the use of an absolute neutrophil count (ANC) threshold that could exclude men with benign ethnic neutropenia, which afflicts 6.7-8% of black patients and could lead to the exclusion of patients despite having healthy immune systems. Methods: We identified 401 interventional prostate cancer clinical trials with an overall survival endpoint. The list of trials was collected on January 16, 2017 from clinicaltrials.gov using the following criteria – study type: interventional studies; conditions: prostate cancer; interventions: drug; outcome measures: overall survival. Characteristics gathered from each trial included sponsor type, phase, accrual goal, start year, and toxicity. Results: Overall, 47.9% (192) of these trials used either sCr alone and/or required participants to have ANC ≥1.5×109 cells/L. Specifically, 25.2% (101) of the trials used sCr alone to determine eligibility, and 41.4% (166) of the trials required patients to have an ANC ≥1.5×109 cells/L. Conclusions: Of clinical trials in prostate cancer, 47.9% used criteria that disproportionately excluded black patients. The reevaluation of these two eligibility criteria could improve minority trial enrollment. First, lowering the ANC cutoff for patients with benign ethnic neutropenia would increase the number of eligible black participants, as 89% of these patients have an ANC ≥1.0×109 cells/L. Second, using race-adjusted equations for renal function would take into account racial differences in creatinine. While adopting race-based differences in trial criteria may add slight logistical challenges when ensuring patients meet trial eligibility, these adjustments would prevent healthy patients from being excluded solely because of benign laboratory differences caused by their race.

Early versus delayed initiation of salvage androgen deprivation therapy and the risk of prostate cancer-specific mortality

189

Background: We sought to ascertain whether there is an association between prostate cancer (PC)-specific mortality (PCSM) and salvage androgen deprivation therapy (ADT) timing amongst men with short versus long prostate-specific antigen doubling times (PSA-DT)s. Methods: The study cohort was selected from 206 men with localized unfavorable-risk PC who were randomized to radiation therapy (RT) or RT plus 6 months of ADT between 1995 and 2001. Fifty-four men who received salvage ADT for PSA failure after a median follow up of 18.72 years following randomization defined the study cohort. Fine-Gray competing risks regression analyzed whether the timing of salvage ADT was associated with an increased risk of PCSM after adjusting for age, comorbidity, known PC prognostic factors, and previously identified interactions. Results: After a median follow-up of 5.68 years (IQR 3.05 - 9.56) following salvage ADT 49 of the 54 men (91%) died, 27 from PC (54% of deaths). Increasing PSA-DT as a continuous covariate was associated with a decreasing risk of PCSM (adjusted hazard ratio [AHR] 0.33, 95% CI 0.13, 0.82; P=0.02). Amongst men with a long PSA-DT (≥6 months), initiating salvage ADT later (PSA>12ng/mL, upper quartile) versus earlier was associated with an increased risk of PCSM (AHR 8.84, 95% CI 1.99-39.27; P=0.004); whereas for men with a short (<6 months) PSA-DT (AHR 1.16, 95% CI 0.38-3.54; P=0.79) this was not true. Conclusions: Early initiation of salvage ADT for post-RT PSA recurrence in men with a PSA-DT of 6 months or more may reduce the risk of PCSM, arguing against the unproven assumption that patients with a short PSA-DT are those most likely to benefit from early initiation of salvage ADT. Clinical trial information: NCT00116220.

Practice patterns and outcomes among patients with N0M0 prostate cancer and a very high prostate-specific antigen

48

Background: There are limited data regarding practice patterns and outcomes among patients with a very high prostate-specific antigen (PSA) level ( > = 98.0 ng/mL) but clinically localized (N0M0) prostate cancer. Methods: We used the National Cancer Database (NCDB) to identify 748,825 patients with prostate cancer diagnosed 2004-2012. We subdivided these patients by PSA level (0-9.9, 10-19.9, 20-39.9, 40-59.9, 60-79.9, 80-97.9, and > = 98.0 ng/mL), nodal status (N0 vs N1) and the presence of distant metastases (M0 vs M1). We determined the rate of definitive LR therapy (pelvic and/or prostate radiation and/or radical prostatectomy) in each group. Overall survival was compared using Cox multivariable regression modeling after adjusting for patient race, income quartile, education quartile, age, and year of diagnosis. Results: Rates of definitive LR therapy for patients with PSA > = 98.0 ng/mL and N0M0 disease were significantly lower than they were for those with N1M0 disease (52.6% vs 60.4%, p < 0.001) or with PSA < 98.0 ng/mL and N0M0 disease (52.6% vs 86.6%, p < 0.001). Among patients with N0M0 disease, 5-year OS decreased with increasing PSA: for PSA levels of 0-9.9, 10-19.9, 20-39.9, 40-59.9, 60-79.9, 80-97.9, and > = 98.0 ng/mL, 5-year OS was 91.6%, 84.3%, 80.2%, 84.1%, 81.8%, 80.2%, and 59.1%, respectively. Among those with N1M0 disease, 5-year OS was 63.2%, which in multivariable Cox regression modeling was not significantly different compared to those with PSA > = 98.0 ng/mL N0M0 disease (adjusted hazard ratio [AHR] 0.99, 95% confidence interval 0.91-1.09, p = 0.942). The survival benefit associated with LR treatment was larger among those with N0M0 high-PSA disease than among those with N1M0 disease (AHR of 0.26 vs 0.41, p-interaction < 0.001). Conclusions: Patients with clinically N0M0 disease but very high PSA ( > = 98.0 ng/mL) have similar outcomes as patients with N1 disease but receive definitive LR therapy at a lower rate. It is possible that patients with N0M0 disease and PSA > = 98.0 ng/mL represent a population that should be treated as more similar to the N1M0 population, rather than the M1 population, including consideration of LR therapy in appropriate contexts.

Identification of low prostate-specific antigen, high Gleason prostate cancer as a unique hormone-resistant entity with poor survival: A contemporary analysis of 640,000 patients

5080

Background: The clinical implications of a low prostate-specific antigen (PSA) in high-grade prostate cancer are unclear. We examined the prognostic and predictive value of a low PSA in high-grade prostate cancer. Methods: We identified 642,975 patients in the National Cancer Database (n = 491,505) and Surveillance, Epidemiology, and End Results program (n = 151,470) with localized or locally advanced prostate cancer from 2004-2013. Patients were stratified by Gleason score (8-10 vs. ≤7) and PSA (≤2.5, 2.6-4.0, 4.1-10.0, 10.1-20.0, and > 20.0 ng/mL) for analyses. Multivariable Fine-Gray competing risks and Cox regressions were used to analyze prostate-cancer specific mortality (PCSM) and all-cause mortality (ACM), respectively. Results: 5.6% of Gleason 8-10 tumors were diagnosed with PSA ≤2.5 ng/mL. Among Gleason 8-10 disease using PSA 4.1-10.0 ng/mL as referent, PCSM was U-shaped with respect to PSA, with adjusted hazard ratio (AHR) of 1.75 (95% CI 1.05-2.92, P = 0.032) for PSA ≤2.5 ng/mL vs. 1.31, 0.88, and 1.60 for PSA 2.6-4.0, 10.1-20.0, and > 20.0 ng/mL. In contrast, PCSM was linear for Gleason ≤7 disease with AHR of 0.32 (95% CI 0.10-1.00, P = 0.050) for PSA ≤2.5 ng/mL vs. 1.13, 1.69, and 3.22 for PSA 2.6-4.0, 10.1-20.0, and > 20.0 ng/mL (PGleason*PSA interaction< 0.001). Gleason 8-10 disease with PSA ≤2.5 ng/mL had a much higher risk of PCSM than standard NCCN high-risk disease (AHR 1.92, 95% CI 1.18-3.14, P = 0.009; 47-month PCSM 14.0% vs. 10.5%). For Gleason 8-10 tumors treated with definitive radiotherapy, androgen deprivation therapy (ADT) was associated with decreased ACM for PSA > 2.5 ng/mL (AHR 0.87, 95% CI 0.81-0.94, P < 0.001) but trended toward increased ACM for PSA ≤2.5ng/mL (AHR 1.27, 95% CI 0.89-1.81, P = 0.194; PADT*PSA interaction= 0.026). Conclusions: Low PSA, high-grade prostate cancer appears to be a unique hormone-resistant entity with a high risk of PCSM that responds poorly to standard treatment. Further molecular classification and trials are urgently needed to develop biological insight into this entity and establish new treatment paradigms, potentially including chemotherapy or novel systemic agents.

Outcomes for men under 65 with high-risk prostate cancer with Medicaid versus private insurance

198

Background: Increased Medicaid coverage, due to the Affordable Care Act, has been hypothesized to reduce racial disparities. We therefore examined the association between private insurance vs. Medicaid, race, and outcomes for the treatment of high-risk prostate cancer (CaP) among men < 65 years old. Methods: The Surveillance, Epidemiology, and End Results Program identified 116,853 men < 65 diagnosed with CaP from 2007-2011. Multivariable logistic regression modeled the association between insurance status (IS) and stage at presentation. Among men with high-risk CaP, the associations between IS and receipt of definitive therapy (DT) and prostate cancer-specific mortality (PCSM) were determined using multivariable logistic and Fine and Gray competing-risks regression models, respectively. Results: Compared to privately insured men, those with Medicaid were more likely to present with metastatic disease (Mets) (adjusted odds ratio (AOR) 5.79; 95% confidence interval (CI) 5.25-6.40; P < 0.001). Among men with high-risk disease, men with Medicaid were less likely to receive DT (AOR 0.55; 95% CI 0.51-0.60; P < 0.001) and had increased PCSM (adjusted hazard ratio (AHR) 1.8; 95% CI 1.27-2.54; P = 0.001). There were significant interactions (INT) between race and Medicaid for the outcomes of PCSM (PINT= 0.05) and Mets (PINT= 0.003). Specifically, gaps in PCSM and Mets were observed among privately insured men, with increased PCSM (AHR 1.51; 95% CI 1.18-1.94; P = 0.001) and Mets (AOR 1.33; 95% CI 1.20-1.48; P < 0.001), while there were no observed disparities among men with Medicaid with regards to PCSM (AHR 0.72; 95% CI 0.34-1.52; P = 0.387) and Mets (AOR 1.03 95% CI 0.86-1.24; P = 0.730). Conclusions: Among men with CaP, African American men are more likely to present with Mets, less likely to receive DT, and have increased PCSM compared to non-black men. These disparities are observed in heterogeneous privately insured cohorts. However, among men with Medicaid, outcomes were equally worse. Furthermore, there was a significant INT between race and IS, indicating more-than-additive effects. Our study suggests that while increased access to Medicaid could act to reduce disparities seen in CaP, outcomes need to be improved overall.

National predictors and trends for androgen deprivation therapy use in low-risk prostate cancer

50

Background: Androgen deprivation therapy (ADT) is not recommended for low-risk prostate cancer due to its known harms and lack of benefits. We evaluated the incidence and predictors of ADT use in men with low-risk prostate cancer. Methods: We identified 197,980 patients in the National Cancer Database (NCDB) with low-risk prostate cancer (Gleason 3+3 = 6, PSA < 10ng/mL, and cT1-T2a) diagnosed from 2004 to 2012 with complete demographic and treatment information. We determined the incidence of ADT use and utilized multiple logistic regression to evaluate predictors of ADT use. Results: ADT use in low-risk prostate cancer patients declined steadily from 2004 to 2012 (17.6% vs. 3.5%). 80.6% of these patients underwent radiation, and 10.0% received ADT as primary therapy. Among 82,354 low-risk disease patients treated with radiation, demographic and treatment factors associated with increased likelihood of ADT use include older age (adjusted odds ratio [AOR] 1.04 per year, p < 0.001); Hispanic vs. non-Hispanic white ethnicity (18.9% vs. 17.8%, AOR 1.26, p < 0.001); having Medicare at age < 65 (15.3%, AOR 1.14, p = 0.008) or Medicare at age ≥ 65 (21.5%, AOR 1.11, p < 0.001) vs. private insurance (13.9%); having bottom quartile vs. top quartile income (19.4% vs. 16.3%, AOR 1.26, p < 0.001); being treated in a community cancer program (22.0%, AOR 1.60, p < 0.001) or a comprehensive community cancer program (18.7%, AOR 1.38, p < 0.001) vs. an academic/research cancer program (13.9%); and receiving brachytherapy vs. external beam radiation therapy (19.3% vs. 15.5%, AOR 1.32, p < 0.001). Increasing distance from the treatment facility was associated with decreased likelihood of receiving ADT (AOR 0.97 for every 100 miles, p = 0.001). Conclusions: Among men with low-risk prostate cancer, increasing age, Hispanic ethnicity, Medicare insurance, lower income level, treatment in a non-academic/research cancer program, and brachytherapy use were all associated with increased odds of receiving ADT. Given the lack of evidence supporting ADT use in low-risk disease and increasing evidence of its many side-effects, it is critical to understand why low-risk prostate cancer patients are still receiving ADT so that this practice may be reduced.

Racial disparities in prostate cancer outcome among prostate-specific antigen screening eligible populations in the United States

18

Background: In 2012, the United States Preventive Services Task Force (USPSTF) recommended against Prostate-Specific Antigen (PSA) screening, despite evidence that Black men are at a higher risk of prostate cancer-specific mortality (PCSM). We evaluated whether Black men of potentially screening-eligible age (55-69) are at a disproportionally high risk of poor outcomes. Methods: The SEER database was used to study 390,259 men diagnosed with prostate cancer in the United States between 2004-2011. Multivariable logistic regression modeled the association between Black race and stage of presentation, while Fine-Gray competing risks regression modeled the association between Black race and PCSM, both as a function of screening eligibility (age 55-69 vs not). Results: Black men were more likely to present with metastatic disease (adjusted odds ratio [AOR] 1.65; 1.58-1.72; P< 0.001) and were at a higher risk of PCSM (adjusted hazard ratio [AHR] 1.36; 1.27-1.46; P< 0.001) compared to Non-Black men. There were significant interactions between race and PSA-screening eligibility such that Black patients experienced more disproportionate rates of metastatic disease (AOR 1.76; 1.65-1.87 vs. 1.55; 1.47-1.65; Pinteraction< 0.001) and PCSM (AHR 1.53; 1.37-1.70 vs. 1.25; 1.14-1.37; Pinteraction= 0.01) in the potentially PSA-screening eligible group than in the group not eligible for screening. Conclusions: Racial disparities in prostate cancer outcome among Black men in are significantly worse in PSA-screening eligible populations. These results raise the possibility that Black men could be disproportionately impacted by recommendations to end PSA screening in the United States and suggest that Black race should inform clinical decisions on PSA screening.

Trends and clinico-sociodemographic determinants of stereotactic body radiotherapy use for localized prostate cancer: A National Cancer Database study

e545

Background: Stereotactic body radiotherapy (SBRT) represents an emerging and cautiously guideline-approved definitive therapy option for prostate cancer, though long-term data on efficacy and toxicity is still pending. Herein, we sought to determine contemporary national SBRT trends and clinico-sociodemographic determinants associated with its use in prostate cancer. Methods: The National Cancer Data Base (NCDB) was queried to identify 181,544 patients diagnosed with localized prostate cancer from 2004-2012 who received external beam radiotherapy. Multivariable logistic regression adjusted for sociodemographic and clinical factors was used to identify independent determinants of SBRT use. Results: Rate of SBRT use for localized prostate cancer increased from 0.05% in 2004 to 4.87% in 2012 ( Ptrend< 0.001). SBRT was more likely to be delivered at academic centers, to patients with Medicare, and to patients who were white, younger, healthier, from wealthier and more educated zipcodes, and who had lower risk disease features (all P< 0.001). Relative to Whites, men from more affluent zipcodes, or men with low stage or grade prostate cancer, Blacks, Hispanics, and men from less affluent zipcodes and men with high stage or grade prostate cancer were less likely to receive SBRT after multivariable adjustment, with adjusted hazard ratios of 0.66, 0.35, 0.33, 0.07, and 0.21, respectively (all P< 0.001). Conclusions: The absolute national rate of SBRT use as definitive therapy for prostate cancer has increased nearly 100-fold over the last decade. Men who are White, younger, healthier, from more affluent zipcodes and with favorable disease characteristics are more likely to receive an emerging form of radiotherapy with unknown long-term efficacy and toxicity.

Socioeconomic disparities in the receipt of radiation for node-positive prostate cancer

53

Background: Radiation therapy in the setting of node-positive prostate cancer has been controversial, although some recent data suggests a survival benefit to radiation in this setting. We evaluated socioeconomic disparities in the receipt of radiation for node-positive prostate cancer to identify groups that may be less likely to receive this potentially life-saving treatment. Methods: We identified 3,283 patients with N1M0 prostate cancer diagnosed 1982-2011 using the Surveillance, Epidemiology, and End Results database who were treated with radiation or no local therapy. We conducted multivariable logistic regression to determine socioeconomic predictors of not receiving radiation treatment. Results: Several patient and demographic factors were associated with a reduced likelihood of receiving radiation: African American (AA) vs non-AA race (31.7% vs. 37.7%, adjusted odds ratio [AOR] 0.74, p = 0.012); unmarried vs married status (31.9% vs 38.6%, AOR 0.72, p < 0.001); bottom third vs top third in income level (33.7% vs. 39.8%, AOR 0.72, p < 0.001); age over 65 versus < = 65 years (34.6% vs 39.8%, AOR 0.81, p = 0.005); diagnosis before 2000 versus starting in 2000 (31.6% vs 43.5%, AOR 0.56, p < 0.001). In a separate analysis, patients under the age of 65 who had Medicaid or no insurance were less likely than patients with other insurance to receive radiation (43.5% vs 55.9%, OR 0.61, p = 0.041), although on multivariable analysis, no significant association persisted (p = 0.512). Conclusions: African American race, unmarried status, lower income level, older age, and insurance status were all associated with significantly reduced odds of receiving radiation therapy for node-positive prostate cancer compared with no local therapy. Given the accumulating data suggesting that radiation therapy can improve survival in node-positive patients, it is increasingly important to understand the reasons for these treatment disparities so that they can be reduced.

Variation in national use of long-term ADT by disease aggressiveness among men with unfavorable-risk prostate cancer

54

Background: Current National Comprehensive Cancer Network (NCCN) guidelines uniformly recommend long-term androgen deprivation therapy (ADT) for all men with high-risk prostate cancer. We sought to determine whether the use of long-term ADT varied by the subcategory of disease, including the recently-defined subcategories of high-risk disease (favorable, other, and very-high) versus intermediate-risk disease. Methods: We identified 5,836 patients with NCCN intermediate-, high-, or very high-risk prostate cancer diagnosed between 2004 and 2007 and managed with external beam radiation therapy (EBRT) using the Surveillance, Epidemiology, and End Results database linked to Medicare claims data. Patients were stratified by risk group: intermediate-risk, favorable high-risk (previously defined and validated as T1c, Gleason 4+4=8, PSA < 10 ng/mL or T1c, Gleason 6, PSA > 20 ng/mL), other high-risk, or very high-risk. We used competing risks regression to estimate the rates of long-term (≥ 2 years) ADT in each of these groups. Differences were compared using multivariable regression modeling, adjusting for year of diagnosis, race, marital status, income level, age, and comorbidity. Results: Men with favorable high-risk prostate cancer were significantly less likely to receive 2 years of ADT than others with high-risk disease (21.9% vs. 29.3%, adjusted hazard ratio [AHR] 0.78, 95% confidence interval [CI] 0.67-0.90, p = 0.001), and similarly likely as those with intermediate-risk disease (AHR 1.08, 95% CI 0.94-1.25, p = 0.288). Others with high-risk disease were less likely to receive 2 years of ADT than those with very high-risk cancer (29.3% vs 36.4%, AHR 0.84, 95% CI 0.74-0.96, p = 0.010). Conclusions: Patients with EBRT-managed high-risk prostate cancer received significantly different rates of long-course ADT based on subclassification. Despite NCCN guidelines recommending long-term ADT for all high-risk or very high-risk prostate cancer, our results might reflect the view that these patients represent a heterogeneous group, with favorable high-risk cancer possibly warranting less aggressive therapy than other high-risk or very high-risk disease.

The association of very low PSA with increased cancer-specific death in men with high-grade prostate cancer

62

Background: It has been hypothesized that very low PSAs in men with high-grade prostate cancer could reflect dedifferentiation and a poorer prognosis, but clinical evidence to support this is limited. We sought to determine whether a very low-presenting PSA was associated with greater prostate cancer-specific mortality (PCSM) among men with Gleason score (GS) 8-10 disease. Methods: The Surveillance, Epidemiology and End Results Program was used to identify a national cohort of 328,904 men diagnosed with cT1-4N0M0 prostate cancer between 2004 and 2010. Multivariable Fine-Gray competing-risks regression analysis was used to determine PCSM as a function of PSA level (<2.5 ng/mL, 2.6-4 ng/mL, 4.1-10 ng/mL, 10.1-20 ng/mL, 20.1-40 ng/mL, or >40ng/mL) and GS (8-10 vs. <=7). Results: Median follow-up was 38 months. Among men with GS 8-10 disease, using PSA 4.1-10 as the reference group, the Adjusted HR (AHR) for PCSM for men with PSA level <2.5 was 1.86 (95% CI 1.51-2.29; P<0.001), PSA 2.6-4 was1.44 (1.17-1.78; P<0.001), PSA 10.1-20 was 1.58 (1.39-1.78; P<0.001), PSA 20.1-40 was 2.04 (1.78-2.33; P<0.001), and PSA>40 was 3.19 (2.83-3.59; P<0.001), suggesting a U-shaped distribution. There was a significant interaction between PSA level and GS (Pinteraction<0.001) such that PSA <2.5 only significantly predicted for poorer PCSM among patients with high grade GS 8-10 disease. Conclusions: Among patients with high grade GS 8-10 disease, patients with PSA <2.5 and 2.6-4 appear to have a higher risk for cancer-specific death compared to patients with a 10.1-20 PSA level, supporting the notion that low PSA in GS 8-10 disease may be a sign of underlying aggressive and extremely poorly differentiated or anaplastic low PSA-producing tumors. Patients with low PSA GS 8-10 disease should be considered for clinical trials studying the use of chemotherapy and other novel agents in very-high risk prostate cancers.

Incidence and predictors of prostate cancer death in men with other prior malignancies: An analysis from SEER Database

34

Background: Men with cancer are screened 22% more for prostate cancer (PCa) than men without cancer, yet very little has been published on their prostate cancer outcomes. We aim to describe PCa death and clinical factors associated with dying from PCa in this population. Methods: We studied 22,769 men in the Surveillance, Epidemiology, and End Results database diagnosed with PCa as a second cancer from 1973 to 2006. Proportions of PCa death versus primary-cancer death were calculated, stratified by the nine primary cancers with highest incidence among US men and then further stratified by PCa grade and interval between primary and PCa diagnoses. Results: Urinary-bladder (30.4%), colorectal (27.9%) and lung cancer (10.5%) were the most common primary cancers. Overall, 12.4% of men died from PCa. A greater proportion of patients died from PCa than their first cancer with primary melanoma (11.7 vs 6.97%) and oral cavity/pharynx cancer (15.3 vs 6.98%), a similar proportion for colorectal (14.8% vs 13.7%) and kidney/renal pelvis cancer (11.1 vs 12.7%), but a lower proportion for lung (11.3 vs 42.1%) and bladder cancer (10.8 vs 17.4%). When the interval between cancer diagnoses was more than 5 years, PCa was the leading cause of death for five of the nine cancers. Patients who died from PCa compared to those who died from their primary had higher baseline PSA (39.5 vs 16.9 ng/mL, p<0.001), more Gleason 8-10 (36.7 vs 18.2%, p<0.001), more N1/M1 PCa (2.35 vs 0.30%, p<0.001), were older at PCa diagnosis (74.7 vs 71.9 years, p=0.015), and had a longer interval between diagnoses (63.9 vs 28.8 months, p<0.001). Conclusions: PCa remains a significant cause of mortality when diagnosed as a second cancer, especially if the interval from prior cancer is greater than 5 years, suggesting that treatment of aggressive prostate cancer may be reasonable for many patients with prior cancers.

Incidence and predictors of upgrading and upstaging among 10,000 contemporary patients with low-risk prostate cancer

32

Background: To inform decisions about active surveillance, we determined the incidence of upgrading and upstaging for a contemporary cohort of low-risk prostate cancer patients who received radical prostatectomy and identified clinical predictors of advanced disease. Methods: We studied 10,273 patients in the Surveillance, Epidemiology, and End Result (SEER) database diagnosed with low-risk prostate cancer (cT1c-T2a, PSA<10 ng/mL and Gleason 3+3=6) in 2010-2011. Upgrading was defined as pathologic Gleason score 7-10 and upstaging as pathologic T3-T4/N1 disease. Regression coefficients were used to evaluate the predictive value of clinical factors for upgrading or upstaging. Significant factors were used to develop a risk stratification table to evaluate individual patients. Results: At prostatectomy, 44% of patients were upgraded and 9.7% were upstaged. Multivariable analysis showed age, PSA, and percent total cores positive were associated with advanced disease (all p<0.001). When these variables were dichotomized by the median, age >60 (Adjusted Odds Ratio [AOR] 1.39), PSA>5.0 (AOR 1.28), and >25% total cores positive (AOR 1.76) were significantly associated with upgrading (all p<0.001). Similarly, age>60 (AOR 1.42), PSA>5.0 (AOR 1.44), and >25% total cores positive (AOR 2.26) were associated with upstaging (all p<0.001). Sixty percent of low-risk patients with PSA 7.5-9.9 and >25% total cores positive were upgraded. Conclusions: A significant proportion of low-risk patients eligible for active surveillance were harboring more aggressive or locally-advanced prostate cancer. Age, PSA and percent total cores positive should be used to assess risk of upgrading or upstaging and can guide decisions to pursue further evaluation or treatment. [Table: see text]

Can pelvic lymph node dissection be omitted in intermediate-risk prostate cancer patients? A SEER-based comparative study using inverse-probability-of-treatment weighting

95

Background: To investigate whether pelvic lymph node dissection (PLND) reduces prostate cancer specific mortality (PCSM) in surgically-treated men with intermediate-risk prostate cancer (Pca). Methods: We identified 44,112 men diagnosed with intermediate-risk Pca from 2004-2009 in Surveillance, Epidemiology and End Results Program (SEER). We used inverse-probability-of-treatment weighting (IPTW) to adjust for baseline characteristics between PLND + radical prostatectomy (RP, N=26,571), versus RP alone (N=17,541) groups; Cox competing-risk model and propensity score-adjusted analyses were used for validation. Gleason scores were based on prostatectomy since biopsy scores were not available for RP-treated patients in SEER from 2004-2009. Results: After a median follow-up of 54 months, there was no survival benefit associated with PLND + RP compared to RP alone (Gray's test, P=0.30). After IPTW adjustment for baseline characteristics, PLND was still not associated with PCSM (AHR: 0.93, 95% CI: 0.65-1.33). This result was consistent with propensity score-adjusted model (AHR=1.05, 95% CI: 0.71-1.55) and the Cox competing-risk model (AHR=1.06, 95% CI: 0.71-1.57). Of men who received RP with PLND, 502 men (1.9%) had pathologically positive lymph nodes, which were associated with a higher risk for PCSM (AHR: 4.02, 95%CI: 1.83-8.84). Conclusions: PLND with RP was not associated with reduced PCSM compared with RP alone in men with intermediate-risk disease, suggesting that PLND is diagnostic but not therapeutic in this patient population. However, a caveat of this study is that risk group was defined by pathologic Gleason score; the 5% of clinically intermediate risk patients who are typically found to have Gleason 8-10 disease at prostatectomy could not be included in this analysis. [Table: see text]

Incidence and determinants of 1-month mortality after cancer-directed surgery

282

Background: Death within 1 month of surgery is considered treatment related and serves as an important healthcare quality metric. We sought to identify the incidence of and factors associated with 1-month mortality after cancer-directed surgery. Methods: We used the Surveillance, Epidemiology and End Results Program to study a cohort of 1,110,236 patients diagnosed from 2004-2011 with cancers that are among the 10 most common or most fatal who received cancer-directed surgery. Multivariable logistic regression analyses were used to identify factors associated with 1-month mortality after cancer-directed surgery. Results: 53,498 patients (4.8%) died within 1 month of cancer-directed surgery. Patients who were married, insured, or who had a top 50th percentile income or educational status had lower odds of 1-month mortality from cancer-directed surgery ([adjusted odds ratio (AOR) 0.80; 95% CI 0.79 – 0.82; P<0.001], [AOR 0.88; (0.82 – 0.94); P<0.001], [AOR 0.95; (0.93 – 0.97); P<0.001], and [AOR 0.98; (0.96 – 0.99); P=0.043], respectively). Patients who were non-white minority, male, or older (per year increase), or who had advanced tumor stage 4 disease all had a higher risk of 1-month mortality after cancer-directed surgery, with AORs of 1.13 (1.11 – 1.15), P<0.001; 1.11 (1.08 – 1.13), P<0.001; 1.02 (1.02 – 1.03), P<0.001; and 1.89 (1.82 – 1.95), P<0.001 respectively. Conclusions: Unmarried, uninsured, non-white, male, older, less educated, and poorer patients were all at a significantly higher risk for death within 1 month of cancer-directed surgery. Efforts to reduce 1-month surgical mortality and eliminate sociodemographic disparities in this adverse outcome could significantly improve survival among patients with cancer.