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

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 (40ng/mL) and GS (8-10 vs. 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

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

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

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

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

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

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