Phase II and Biomarker Study of Cabozantinib in Metastatic Triple-Negative Breast Cancer Patients.

Currently, no targeted therapies are available for metastatic triplenegative breast cancer (mTNBC). We evaluated the safety, efficacy, and biomarkers of response to cabozantinib, a multikinase inhibitor, in patients with mTNBC. We conducted a single arm phase II and biomarker study that enrolled patients with measurable mTNBC. Patients received cabozantinib (60 mg daily) on a 3-week cycle and were restaged after 6 weeks and then every 9 weeks. The primary endpoint was objective response rate. Predefined secondary endpoints included progression-free survival (PFS), toxicity, and tissue and blood circulating cell and protein biomarkers. Of 35 patients who initiated protocol therapy, 3 (9% [95% confidence interval (CI): 2, 26]) achieved a partial response (PR). Nine patients achieved stable disease (SD) for at least 15 weeks, and thus the clinical benefit rate (PR+SD) was 34% [95% CI: 19, 52]. Median PFS was 2.0 months [95% CI: 1.3, 3.3]. The most common toxicities were fatigue, diarrhea, mucositis, and palmar-plantar erythrodysesthesia. There were no grade 4 toxicities, but 12 patients (34%) required dose reduction. Two patients had TNBCs with MET amplification. During cabozantinib therapy, there were significant and durable increases in plasma placental growth factor, vascular endothelial growth factor (VEGF), VEGF-D, stromal cell-derived factor 1a, and carbonic anhydrase IX, and circulating CD3 + cells and CD8 + T lymphocytes, and decreases in plasma soluble VEGF receptor 2 and CD14+ monocytes (all p < .05). Higher baseline concentrations of soluble MET (sMET) associated with longer PFS (p = .03). In conclusion, cabozantinib showed encouraging safety and efficacy signals but did not meet the primary endpoint in pretreated mTNBC. Exploratory analyses of circulating biomarkers showed that cabozantinib induces systemic changes consistent with activation of the immune system and antiangiogenic activity, and that sMET should be further evaluated a potential biomarker of response. IMPLICATIONS FOR PRACTICE: Triple-negative breast cancer (TNBC)-a disease with a dearth of effective therapies-often overexpress MET, which is associated with poor clinical outcomes. However, clinical studies of agents targeting MET and VEGF pathways-alone or in combination-have shown disappointing results. This study of cabozantinib (a dual VEGFR2/MET) in metastatic TNBC, while not meeting its prespecified endpoint, showed that treatment is associated with circulating biomarker changes, and is active in a subset of patients. Furthermore, this study demonstrates that cabozantinib therapy induces a systemic increase in cytotoxic lymphocyte populations and a decrease in immunosuppressive myeloid populations. This supports the testing of combinations of cabozantinib with immunotherapy in future studies in breast cancer patients.

Metformin and prostate cancer mortality: a meta-analysis.

PURPOSE: Observational studies report conflicting results on the association between metformin exposure and prostate cancer outcomes. This meta-analysis summarizes studies reporting overall survival, prostate cancer-specific mortality, and biochemical recurrence. METHODS: PubMed and Embase were systematically reviewed to identify studies investigating the association between metformin use and clinical endpoints among men with prostate cancer while taking confounding by diabetes diagnosis into account. Pooled risk estimates (hazard ratios, HRs) and 95 % confidence intervals (CIs) were calculated using random-effects models. Sensitivity analyses for quality components and factors for heterogeneity were conducted. RESULTS: Of 549 articles identified, nine retrospective cohort studies representing 9,186 patients were included. There was significant heterogeneity between studies, and studies differed in quality. Metformin use was associated with improved overall survival in studies with clear risk window definition (HR 0.88, 95 % CI 0.86-0.90, p < 0.001) and in studies with potential immortal time bias (HR 0.52, 95 % CI 0.41-0.65, p < 0.001). No significant association with prostate cancer-specific mortality was detected (HR 0.76, 95 % CI 0.44-1.31, p = 0.33). Metformin use was associated with a decreased risk of biochemical recurrence (HR 0.79, 95 % CI 0.63-1.00, p = 0.047). CONCLUSIONS: This meta-analysis suggests a benefit of metformin in men with diabetes and prostate cancer. However, further carefully designed studies are needed to confirm findings and to assess potential generalization to non-diabetic, non-white, and less aggressively treated men with prostate cancer.

Risk of prostate cancer mortality in men with a history of prior cancer.

OBJECTIVES: To describe outcomes of patients with prostate cancer diagnosed after another malignancy and identify factors associated with prostate cancer death in this population, as little is known about the clinical significance of prostate cancer as a subsequent malignancy. PATIENTS AND METHODS: We studied 18 225 men diagnosed with prostate cancer after another malignancy from 1973 to 2006. We compared demographic and clinical variables, and the proportion of death from prostate cancer vs prior malignancy with t-test and chi-squared analyses. Fine and Gray's regression was used to consider the effect of treatment on prostate cancer death. We then studied a second cohort of 88 013 men with prostate cancer as a first or second malignancy to describe current diagnostic and treatment patterns. RESULTS: One in seven men died from prostate cancer in our first cohort. More died from prostate cancer following colorectal cancer (16.8% vs 13.7%), melanoma (13.4% vs 7.56%), and oral cancer (19.1% vs 4.04%), but fewer following bladder cancer, kidney cancer, lung cancer, leukaemia and non-Hodgkin's lymphoma (all P < 0.001). Prostate cancer treatment was associated with a nearly 50% lower risk of death when high-grade or high-stage (adjusted hazard ratio 0.55, 95% confidence interval [CI] 0.47-0.64). Patients who died from prostate cancer had higher grade and stage disease, and received less treatment than patients who died from prior malignancy. The second cohort showed subsequent prostate cancer had more high-risk disease (36.3% vs 22.2%, P < 0.001) and less prostate cancer treatment (adjusted odds ratio 0.872, 95% CI 0.818-0.930) than primary prostate cancer. CONCLUSIONS: Prostate cancer remains a significant cause of mortality when diagnosed as a subsequent cancer. These results suggest prostate cancer treatment should be seriously considered in patients with prior malignancies, especially those with high-grade or locally advanced prostate cancer.

Incidence and Predictors of Upgrading and Up Staging among 10,000 Contemporary Patients with Low Risk Prostate Cancer.

PURPOSE: We determined the incidence of pathological upgrading and up staging for contemporary, clinically low risk patients, and identified predictors of having occult, advanced disease to inform the selection of patients for active surveillance. MATERIALS AND METHODS: We studied 10,273 patients in the SEER database diagnosed with clinically low risk disease (cT1c/T2a, prostate specific antigen less than 10 ng/ml, Gleason 3 + 3 = 6) in 2010 to 2011 and treated with prostatectomy. The primary outcome was the incidence of upgrading to pathological Gleason score 7-10 or up staging to pathological T3-T4/N1 disease. Multivariable logistic regression of cases with complete biopsy data (5,581) identified significant predictors of upgrading or up staging, which were then used to create a risk stratification table. RESULTS: At prostatectomy 44% of cases were upgraded and 9.7% were up staged. Multivariable analysis of 5,581 patients showed age, prostate specific antigen and percent positive cores (all p < 0.001) but not race were associated with occult, advanced disease. With these variables dichotomized at the median, age older than 60 years (AOR 1.39), prostate specific antigen greater than 5.0 ng/ml (AOR 1.28) and more than 25% positive cores (AOR 1.76) were significantly associated with upgrading (all p < 0.001). Similarly, age older than 60 years (AOR 1.42), prostate specific antigen greater than 5.0 ng/ml (AOR 1.44) and more than 25% positive cores (AOR 2.26) were associated with up staging (all p < 0.001). Overall 60% of 5,581 low risk cases with prostate specific antigen 7.5 to 9.9 ng/ml and more than 25% positive cores were upgraded. This study is limited by possible bias introduced by only using patients selected for prostatectomy. CONCLUSIONS: Nearly half of clinically low risk patients harbor Gleason 7 or greater, or pT3 or greater disease, and should be risk stratified by prostate specific antigen and percent positive cores for consideration of further testing before deciding on active surveillance.

Association of androgen-deprivation therapy with excess cardiac-specific mortality in men with prostate cancer.

OBJECTIVES: To determine if androgen-deprivation therapy (ADT) is associated with excess cardiac-specific mortality (CSM) in men with prostate cancer and no cardiovascular comorbidity, coronary artery disease risk factors, or congestive heart failure (CHF) or past myocardial infarction (MI). PATIENTS AND METHODS: In all, 5077 men (median age 69.5 years) with cT1c-T3N0M0 prostate cancer were treated with brachytherapy with or without neoadjuvant ADT (median duration 4 months) between 1997 and 2006. Fine and Gray competing risks analysis evaluated the association of ADT with CSM, adjusting for age, year of brachytherapy, and ADT treatment propensity score among men in groups defined by cardiac comorbidity. RESULTS: After a median follow-up of 4.8 years, no association was detected between ADT and CSM in men with no cardiac risk factors (1.08% at 5 years for ADT vs 1.27% at 5 years for no ADT, adjusted hazard ratio (AHR) 0.83; 95% confidence interval (CI), 0.39-1.78; P = 0.64; n = 2653) or in men with diabetes mellitus, hypertension, or hypercholesterolaemia (2.09% vs 1.97%, AHR 1.33; 95% CI 0.70-2.53; P = 0.39; n = 2168). However, ADT was associated with significantly increased CSM in men with CHF or MI (AHR 3.28; 95% CI 1.01-10.64; P = 0.048; n = 256). In this subgroup, the 5-year cumulative incidence of CSM was 7.01% (95% CI 2.82-13.82%) for ADT vs 2.01% (95% CI 0.38-6.45%) for no ADT. CONCLUSION: ADT was associated with a 5% absolute excess risk of CSM at 5 years in men with CHF or prior MI, suggesting that administering ADT to 20 men in this potentially vulnerable subgroup could result in one cardiac death.

Lactate transport inhibition therapeutically reprograms fibroblast metabolism in experimental pulmonary fibrosis.

Myofibroblast differentiation, essential for driving extracellular matrix synthesis in pulmonary fibrosis, requires increased glycolysis. While glycolytic cells must export lactate, the contributions of lactate transporters to myofibroblast differentiation are unknown. In this study, we investigated how MCT1 and MCT4, key lactate transporters, influence myofibroblast differentiation and experimental pulmonary fibrosis. Our findings reveal that inhibiting MCT1 or MCT4 reduces TGFß-stimulated pulmonary myofibroblast differentiation in vitro and decreases bleomycin-induced pulmonary fibrosis in vivo. Through comprehensive metabolic analyses, including bioenergetics, stable isotope tracing, metabolomics, and imaging mass spectrometry in both cells and mice, we demonstrate that inhibiting lactate transport enhances oxidative phosphorylation, reduces reactive oxygen species production, and diminishes glucose metabolite incorporation into fibrotic lung regions. Furthermore, we introduce VB253, a novel MCT4 inhibitor, which ameliorates pulmonary fibrosis in both young and aged mice, with comparable efficacy to established antifibrotic therapies. These results underscore the necessity of lactate transport for myofibroblast differentiation, identify MCT1 and MCT4 as promising pharmacologic targets in pulmonary fibrosis, and support further evaluation of lactate transport inhibitors for patients for whom limited therapeutic options currently exist.

Pulmonary amyloidosis as the presenting finding in a patient with multiple myeloma.

We present the case of a 58-year-old man who presented with dyspnea, cough, and weight loss and was ultimately diagnosed with pulmonary amyloidosis and multiple myeloma. Diagnosis was achieved with a lung biopsy which showed AL amyloid deposits involving the interstitium, vessels, and airway. He was treated with cyclophosphamide, bortezomib, and dexamethasone but died prior to completing treatment. His case is unique for the amyloid deposition found in all three lung compartments with clear pathophysiologic manifestations of each compartment, and the rapid disease progression that led to respiratory failure and death.

E-Cigarette Use, Small Airway Fibrosis, and Constrictive Bronchiolitis.

BACKGROUND: Vaping, including the use of electronic cigarettes (e-cigarettes), has become increasingly prevalent, yet the associated long-term health risks are largely unknown. Given the prevalence of use, particularly among adolescents early in their lifespan, it is vital to understand the potential chronic pathologic sequelae of vaping. METHODS: We present the cases of four patients with chronic lung disease associated with e-cigarette use characterized by clinical evaluation, with pulmonary function tests (PFTs), chest high-resolution computed tomography (HRCT), endobronchial optical coherence tomography (EB-OCT) imaging, and histopathologic assessment. RESULTS: Each patient presented with shortness of breath and chest pain in association with a 3- to 8-year history of e-cigarette use, with mild progressive airway obstruction on PFTs and/or chest HRCT findings demonstrating evidence of air trapping and bronchial wall thickening. EB-OCT imaging performed in two patients showed small airway-centered fibrosis with bronchiolar narrowing and lumen irregularities. The predominant histopathologic feature on surgical lung biopsy was small airway-centered fibrosis, including constrictive bronchiolitis and MUC5AC overexpression in all patients. Patients who ceased vaping had a partial, but not complete, reversal of disease over 1 to 4 years. CONCLUSIONS: After thorough evaluation for other potential etiologies, vaping was considered to be the most likely common causal etiology for all patients due to the temporal association of symptomatic chronic lung disease with e-cigarette use and partial improvement in symptoms after e-cigarette cessation. In this series, we associate the histopathologic pattern of small airway-centered fibrosis, including constrictive bronchiolitis, with vaping, potentially defining a clinical and pathologic entity associated with e-cigarette use. (Funded in part by the National Institutes of Health.).

Respiratory Physiology of Prone Positioning With and Without Inhaled Nitric Oxide Across the Coronavirus Disease 2019 Acute Respiratory Distress Syndrome Severity Spectrum.

IMPORTANCE: Prone positioning improves clinical outcomes in moderate-to-severe acute respiratory distress syndrome and has been widely adopted for the treatment of patients with acute respiratory distress syndrome due to coronavirus disease 2019. Little is known about the effects of prone positioning among patients with less severe acute respiratory distress syndrome, obesity, or those treated with pulmonary vasodilators. OBJECTIVES: We characterize the change in oxygenation, respiratory system compliance, and dead-space-to-tidal-volume ratio in response to prone positioning in patients with coronavirus disease 2019 acute respiratory distress syndrome with a range of severities. A subset analysis of patients treated with inhaled nitric oxide and subsequent prone positioning explored the influence of pulmonary vasodilation on the physiology of prone positioning. DESIGN SETTING AND PARTICIPANTS: Retrospective cohort study of all consecutively admitted adult patients with acute respiratory distress syndrome due to coronavirus disease 2019 treated with mechanical ventilation and prone positioning in the ICUs of an academic hospital between March 11, 2020, and May 1, 2020. MAIN OUTCOMES AND MEASURES: Respiratory system mechanics and gas exchange during the first episode of prone positioning. RESULTS: Among 122 patients, median (interquartile range) age was 60 years (51-71 yr), median body mass index was 31.5 kg/m2 (27-35 kg/m2), and 50 patients (41%) were female. The ratio of Pao2 to Fio2 improved with prone positioning in 90% of patients. Prone positioning was associated with a significant increase in the ratio of Pao2 to Fio2 (from median 149 [123-170] to 226 [169-268], p < 0.001) but no change in dead-space-to-tidal-volume ratio or respiratory system compliance. Supine ratio of Pao2 to Fio2, respiratory system compliance, positive end-expiratory pressure, and body mass index did not correlate with absolute change in the ratio of Pao2 to Fio2 with prone positioning. However, patients with ratio of Pao2 to Fio2 less than 150 experienced a greater relative improvement in oxygenation with prone positioning than patients with ratio of Pao2 to Fio2 greater than or equal to 150 (median percent change in ratio of Pao2 to Fio2 62 [29-107] vs 30 [10-70], p = 0.002). Among 12 patients, inhaled nitric oxide prior to prone positioning was associated with a significant increase in the ratio of Pao2 to Fio2 (from median 136 [77-168] to 170 [138-213], p = 0.003) and decrease in dead-space-to-tidal-volume ratio (0.54 [0.49-0.58] to 0.46 [0.44-0.53], p = 0.001). Subsequent prone positioning in this subgroup further improved the ratio of Pao2 to Fio2 (from 145 [122-183] to 205 [150-232], p = 0.017) but did not change dead-space-to-tidal-volume ratio. CONCLUSIONS AND RELEVANCE: Prone positioning improves oxygenation across the acute respiratory distress syndrome severity spectrum, irrespective of supine respiratory system compliance, positive end-expiratory pressure, or body mass index. There was a greater relative benefit among patients with more severe disease. Prone positioning confers an additive benefit in oxygenation among patients treated with inhaled nitric oxide.

Understanding critically ill sepsis patients with normal serum lactate levels: results from U.S. and European ICU cohorts.

While serum lactate level is a predictor of poor clinical outcomes among critically ill patients with sepsis, many have normal serum lactate. A better understanding of this discordance may help differentiate sepsis phenotypes and offer clues to sepsis pathophysiology. Three intensive care unit datasets were utilized. Adult sepsis patients in the highest quartile of illness severity scores were identified. Logistic regression, random forests, and partial least square models were built for each data set. Features differentiating patients with normal/high serum lactate on day 1 were reported. To exclude that differences between the groups were due to potential confounding by pre-resuscitation hyperlactatemia, the analyses were repeated for day 2. Of 4861 patients included, 47% had normal lactate levels. Patients with normal serum lactate levels had lower 28-day mortality rates than those with high lactate levels (17% versus 40%) despite comparable physiologic phenotypes. While performance varied between datasets, logistic regression consistently performed best (area under the receiver operator curve 87-99%). The variables most strongly associated with normal serum lactate were serum bicarbonate, chloride, and pulmonary disease, while serum sodium, AST and liver disease were associated with high serum lactate. Future studies should confirm these findings and establish the underlying pathophysiological mechanisms, thus disentangling association and causation.

Exercise performance in patients with post-acute sequelae of SARS-CoV-2 infection compared to patients with unexplained dyspnea.

BACKGROUND: Dyspnea and exercise intolerance are commonly reported post-acute sequelae of SARS-CoV-2 infection (PASC), but routine diagnostic testing is often normal. Cardiopulmonary exercise testing (CPET) offers comprehensive assessment of dyspnea to characterize pulmonary PASC. METHODS: We performed a retrospective cohort study of CPET performed on patients reporting dyspnea and/or exercise intolerance following confirmed Covid-19 between August 1, 2020 and March 1, 2021, and compared them to age- and sex-matched patients with unexplained dyspnea referred for CPET at the same center in the pre-Covid-19 era. FINDINGS: Compared to matched unexplained dyspnea comparators, PASC patients shared similar medical comorbidities and subjective dyspnea at referral (mMRC score 1.6 ± 0.9 vs. 1.4 ± 0.9, P = 0.5). Fifteen (83.3%) PASC patients underwent high resolution computed tomography of the chest, of which half (46.7%) were normal, and 17 (94.4%) patients had pulmonary function testing, of which the majority (76.5%) were normal. All patients underwent CPET, and 12 (67%) had normal findings. Compared to matched comparators, PASC patients had similar peak oxygen consumption, oxygen consumption at ventilatory anaerobic threshold, and ventilatory efficiency measured by the minute ventilation to carbon dioxide production (VE/VCO2) slope. INTERPRETATION: Despite prominent dyspnea, physiological abnormalities on CPET were mild across a range of initial Covid-19 severity and similar to matched comparators referred for dyspnea without antecedent SARS-CoV-2. FUNDING: The project was supported by the NHLBI (R01HL131029, R01HL151841, U10HL110337, T32HL116275) and a KL2 award (5KL2TR002542-02) from Harvard Catalyst.

Production of ribosome-released nascent proteins with optimal physical properties.

The growing interest in protein folding under physiologically relevant conditions has prompted investigations requiring direct comparisons between ribosome-bound and ribosome-released nascent proteins. Such studies, involving the ad hoc release of newly synthesized proteins from stalled ribosomes, demand a release agent able to produce nonaggregated native proteins and preserve the overall nature of the medium. Here, we explore hydroxylamine, a reactant rarely used to release nascent chains, and compare it to other ribosome-release agents: puromycin, RNase A/EDTA, and sodium hydroxide. Ribosome-bound nascent chains corresponding to the sequence of apoHmpH, the Escherichia coli N-terminal domain of Hmp, were used as a model system. Fluorescence anisotropy decays were employed to probe the self-association and overall physical properties of nascent proteins. Gel electrophoresis and RNA chip microfluidic capillary electrophoresis yielded information on the integrity of nascent peptidyl-tRNAs and ribosomes, respectively. Of the four reagents examined, only hydroxylamine releases nascent apoHmpH without causing extensive aggregation or degradation of the ribosome. Hydroxylamine does not introduce large hydrophobic C-terminal modifications and functions at nearly physiological pH. It is therefore a suitable reagent for the ad hoc release of nascent proteins from the ribosome.

Association Between Older Age and Increasing Gleason Score.

INTRODUCTION: In order to help inform the discussion about the risks versus benefits of prostate cancer screening among older men, we determined whether advanced age is associated with a higher probability of harboring high-grade or high-risk disease. PATIENTS AND METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was used to identify 383,039 men diagnosed with prostate cancer in 2004-2011. The percentage of patients diagnosed with low-, intermediate-, or high-risk disease or a Gleason score of 6, 7, or 8 to 10 was calculated by age range. As a secondary analysis, we examined whether this relationship was different in 2010-2011 versus 2007-2008 (before and after the 2009 publication of screening trials). RESULTS: The probability of Gleason score 8 to 10 or high-risk disease increased significantly with increasing age. The percentage of Gleason score 8 to 10 disease among men ages 50 to 54, 70 to 74, and 80 to 84 years was 8.9%, 16.2%, and 28.5%, respectively, and the percentage of high-risk disease was 14.3%, 22.4%, and 38.7% (P < .001). There were similar relationships among men with stage T1c disease. In addition, older men experienced a significant increase in the relative probability of high-risk or high-grade disease from 2007-2008 to 2010-2011. CONCLUSION: In this large US-based cohort, older men had a much higher probability of high-grade or high-risk prostate cancer. Physicians and patients should take into account the higher risk of more aggressive or advanced disease in older men when discussing the risks and benefits of prostate-specific antigen screening with healthy older men with a substantial life expectancy.

Shifting brachytherapy monotherapy case mix toward intermediate-risk prostate cancer.

PURPOSE: The relative use of brachytherapy (BT) for prostate cancer has declined in recent years. In this setting, we sought to determine whether the case mix of BT monotherapy-treated men has changed over time in terms of risk group composition. METHODS AND MATERIALS: The Surveillance, Epidemiology, and End Results database was used to identify 30,939 patients diagnosed with prostate adenocarcinoma between 2004 and 2011 who received BT monotherapy. The case mix of BT monotherapy patients was calculated by patient risk group and year of diagnosis. RESULTS: Between 2004 and 2011, the use of BT monotherapy declined overall. The relative percentage of men undergoing BT with low-risk disease declined by 4.5%, whereas the relative percentage of patients with intermediate-risk disease increased by 4.7%. Non-white patients and those from poorer counties did not show shifts in the risk group makeup of BT monotherapy patients, whereas white patients and those from wealthier counties did. CONCLUSIONS: Although fewer patients with prostate cancer are undergoing BT monotherapy, men with intermediate-risk disease comprised a significantly larger portion of the BT case mix in 2011 compared with 2004. Future research efforts by brachytherapists should be directed toward improving BT technique, optimizing radiation doses, and obtaining long-term followup data for patients with intermediate-risk prostate cancer.

Income inequality and treatment of African American men with high-risk prostate cancer.

PURPOSE: Definitive treatment of high-risk prostate cancer with radical prostatectomy or radiation improves survival. We assessed whether racial disparities in the receipt of definitive therapy for prostate cancer vary by regional income. PATIENTS AND METHODS: A cohort of 102,486 men (17,594 African American [AA] and 84,892 non-Hispanic white) with localized high-risk prostate cancer (prostate-specific antigen >20 ng/ml or Gleason ≥ 8 or stage ≥ cT2c) diagnosed from 2004 to 2010 was identified in the Surveillance, Epidemiology, and End Results database. Income was measured at the census-tract-level. We used multivariable logistic regression to assess patient and cancer characteristics associated with the receipt of definitive therapy for prostate cancer. Multivariable Fine and Gray competing risks analysis was used to evaluate factors associated with prostate cancer death. RESULTS: Overall, AA men were less likely to receive definitive therapy than white men (adjusted odds ratio [AOR] = 0.51; 95% CI: 0.49-0.54; P<0.001), and there was a significant race/income interaction (Pinteraction = 0.016) such that there was a larger racial treatment disparity in the bottom income quintile (AOR = 0.49; 95% CI: 0.45-0.55; P<0.001) than in the top income quintile (AOR = 0.60; 95% CI: 0.51-0.71; P<0.001). After a median follow-up of 35 months, AA men in the bottom income quintile suffered the greatest prostate cancer mortality (adjusted hazard ratio = 1.47; 95% CI: 1.17-1.84; P = 0.001), compared with white men in the top income quintile. CONCLUSIONS: Racial disparities in the receipt of definitive therapy for high-risk prostate cancer are greatest in low-income communities, suggesting that interventions to reduce racial disparities should target low-income populations first.