Role of Fractionation in Local Control of Spinal Metastases Treated with Stereotactic Radiosurgery

PURPOSE/OBJECTIVE(S)

Optimal fractionation of spinal stereotactic radiosurgery (SRS) for spine metastases remains unknown. Retrospective data suggest decreased local failure (LF) with fractionated SRS of brain metastases. We evaluated our institutional outcomes of spinal SRS with the hypothesis that fractionation improves the rate of local failure compared to single-fraction treatment.

MATERIALS/METHODS

This IRB-approved, retrospective analysis included patients with spine metastases treated with spinal SRS between October 2002 and November 2014 with evaluable follow-up imaging and no prior irradiation to the given segment. The exposure of interest was single- or multi-fraction SRS with a primary endpoint of the cumulative incidence of LF with death as a competing risk. We assessed bivariate associations between fractionation and single-fraction equivalent dose (SFED in Gy10) as well as high-risk features, defined as epidural extension (Bilsky Scale), paraspinous extension, and gastrointestinal (GI) vs non-GI primary. We calculated the rates of LF and vertebral body compression fracture (VCF) at 1-year, and assessed LF by fractionation when limited only to courses receiving SFED>18 Gy. We analyzed the association between fractionation and LF using subdistribution hazard ratios (SHR) estimated from competing risks regression with death as a competing risk and adjusting for lesion-specific characteristics as well as SFED to determine contribution of these variables to the estimated effect of fraction number on LF. We calculated relative attenuation for the contribution of SFED to this association, defined as [SHRfractions-SHRfractions+SFED] ÷ [SHRSFED-1].

RESULTS

In 293 patients with 516 spinal segments, lesions treated with single fraction compared to multi-fraction SRS had less epidural (19% vs 36%, p<0.001) and paraspinous (20% vs 35%, p<0.001) extension, more GI histology (17% vs 10%, p = 0.039), received a higher mean SFED (18.3 Gy vs. 16.6 Gy, p<0.001), and had a lower 1-year LF (8% vs 14%, p = 0.02), with no difference in VCF (7% vs. 5%, p = 0.38). After adjusting for high-risk features, single fraction SRS was associated with lower LF (SHR = 0.45, 95% CI 0.24-0.84, p = 0.02). After adjustment for SFED, this association of fractionation was attenuated by 53% and became insignificant (SHR = 0.78, 95% CI 0.44-1.37, p = 0.38). Overall, 1-year LF for SFED>18 Gy was 6% compared to 15% for <18 Gy (p<0.001). When limited to courses with SFED>18 Gy (n = 261), single fraction SRS had no improvement in 1-year LF compared to multi-fraction (6.6% vs 4.6%, p = 0.77).

CONCLUSION

Single fraction SRS was associated with better local control compared to multi-fraction; however, much of this association was attenuated by SFED but not by high-risk features of treated lesions. To clarify the role of fractionation, we have initiated a prospective, randomized trial of single vs. multi-fraction SRS utilizing the same SFED.

Association between health-care system and prostate cancer mortality for African American men with localized and metastatic prostate cancer

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Background: African American (AA) men with prostate cancer (PC) present with more advanced disease and have worse survival than comparable non-Hispanic White (White) men. Recent studies suggest that receiving care within an equal access setting may attenuate these disparities. We hypothesize that AA men receiving care within the Veterans Health Administration (VHA) will have improved outcomes compared to AA men receiving care in the general population as assessed by the Surveillance, Epidemiology, and End Results (SEER) database. Methods: We identified AA men diagnosed with PC between 2004 and 2015 in the VHA and SEER. For comparisons of covariate distributions across subgroups, we used the chi-squared test with continuity correction. We analyzed the cumulative incidence (with 95% confidence intervals (CIs)) of PC specific mortality (PCSM) in the VHA and SEER. Additionally, multivariable Cox proportional hazards models controlling for demographic information were performed. Results: The cohort included 85,409 AA men (VHA: 27,415, SEER: 57,994). Median follow-up was 4.79 years in the VHA and 5.16 years in SEER. In the VHA, AA men were more likely to present with localized disease (VHA 94.7% vs SEER 86.4%, p < 0.001) and less likely to have metastatic disease (3.2% vs 4.3%, p < 0.001). The 5-year cumulative incidence of PCSM was lower for patients in the VHA (VHA: 3.8% [CI: 3.5-4.1%] vs. SEER: 5.0% [CI: 4.8-5.2%], p < 0.001). The PCSM difference was largest in men with metastatic disease. In metastatic patients, cumulative incidence of PCSM at five years was significantly lower in the VHA (VHA 52.5% [CI: 48.0-56.5%] vs. SEER 64.8% [CI: 62.3-67.1%], p < 0.001). In contrast, AA men with localized disease had similar PCSM in the VHA and SEER (VHA 2.4% [CI: 2.2-2.6%] vs. SEER 2.6% [CI: 2.4-2.7%], p = 0.09 at five years). On multivariable analysis, VHA system was associated with lower PCSM [Hazard Ratio (HR): 0.91, p < 0.001]. There was a significant interaction between VHA system and distant metastases at diagnosis [p < 0.001] indicating larger differences in PCSM by healthcare system in metastatic patients as compared to localized patients. VHA system was associated with reduced PCSM in metastatic patients [HR 0.84, p < 0.001] but not in localized patients [HR 0.96, p = 0.13]. Conclusions: AA men in the VHA had a significantly lower incidence of PCSM than those in the SEER database, especially for those who presented with distant metastases at diagnosis. Future work should examine how cost and access to care affect disparities in outcomes for AA men.

Association of Health-Care System with Prostate Cancer-Specific Mortality in African American and Non-Hispanic White Men

BACKGROUND

Disparities in prostate cancer-specific mortality (PCSM) between African American and non-Hispanic White (White) patients have been attributed to biological and systemic factors. We evaluated drivers of these disparities in the Surveillance, Epidemiology and End Results (SEER) national registry and an equal-access system, the Veterans Health Administration (VHA).

METHODS

We identified African American and White patients diagnosed with prostate cancer between 2004-2015 in SEER (N = 311,691) and the VHA (N = 90,749). We analyzed the association between race and metastatic disease at presentation using multivariable logistic regression adjusting for sociodemographic factors, and PCSM using sequential competing-risks regression adjusting for disease and sociodemographic factors.

RESULTS

The median follow-up was 5.3 years in SEER and 4.7 years in the VHA. African American men were more likely than White men to present with metastatic disease in SEER (adjusted odds ratio = 1.23, 95% confidence interval [CI] = 1.17-1.30), but not in the VHA (adjusted odds ratio = 1.07, 95% CI = 0.98-1.17). African American versus White race was associated with an increased risk of PCSM in SEER (subdistribution hazard ratio [SHR] = 1.32, 95% CI = 1.10-1.60), but not in the VHA (SHR = 1.00, 95% CI: 0.93-1.08). Adjusting for disease extent, PSA, and Gleason score eliminated the association between race and PCSM in SEER (aSHR 1.04, 95% CI 0.93-1.16).

CONCLUSIONS

Racial disparities in PCSM were present in a nationally representative registry, but not in an equal-access healthcare system, due to differences in advanced disease at presentation. Strategies to increase healthcare access may bridge the racial disparity in outcomes. Longer follow-up is needed to fully assess mortality outcomes.Disparities between African American and non-Hispanic White (White) patients in cancer-specific mortality have been described across numerous cancer types and healthcare systems[1-5]. The survival gap between African American and White patients with prostate cancer has been well-characterized, with two-fold higher prostate cancer-specific mortality (PCSM) rates among African American patients depending on the setting[1, 6-10]. This disparity has been attributed to differences in prostate cancer biology in African American men, in addition to systemic factors in mediating this disparity, such as differential access to healthcare, Prostate-Specific Antigen (PSA) screening, and distrust in the healthcare system[1, 11-16].The Veterans Health Administration (VHA) is a relatively equal-access healthcare system that treats a large, ethnically diverse population of veterans. The Surveillance, Epidemiology and End Results (SEER) program is a national cancer registry program that collects data from the general United States (US) population. The goals of the present investigation were to 1) Compare PCSM between African American and White men within SEER and the VHA and 2) Identify modifiable system-level contributors to these disparities. We hypothesized that PCSM would be comparable among African American and White men in an equal-access setting, the VHA, but not in a national registry, SEER, and that this disparity in SEER would be in part driven by more advanced disease at presentation.

Effect of healthcare system on prostate cancer-specific mortality in African American and non-Hispanic white men

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Background: Disparities in prostate cancer-specific mortality (PCSM) between African American and non-Hispanic White (White) patients have been attributed to biological differences; however, recent data suggest poorer outcomes may be related to barriers to medical care from the healthcare system in which patients receive care. We sought to evaluate potential drivers of disparities by comparing outcomes between African American and White men in the Surveillance, Epidemiology and End Results (SEER) national cancer registry and a relatively equal-access healthcare system, the Veterans Health Administration (VHA). Methods: We identified African American and White patients diagnosed with prostate cancer between 2004-2015 in the SEER and VHA databases. We analyzed metastatic disease at diagnosis with multivariable logistic regression, and PCSM with cumulative incidence analysis and sequential competing-risks regression adjusting for disease and sociodemographic factors. Results: The SEER cohort included 306,609 men (57,994 [18.9%] African American and 248,615 [81.1%] White) with a median follow-up of 5.3 years (interquartile range [IQR] 2.6-8.1 years), and the VHA cohort included 90,749 men (27,412 [30.2%] African American and 63,337 [69.8%] White) with a median follow-up of 4.7 years (IQR 2.4-7.6 years). In SEER, African American men were significantly more likely to present with metastatic disease (African American 4.3% versus White 3.0%, p< 0.001; multivariable odds ratio [OR] 1.25, 95% confidence interval [CI] 1.19-1.32, p< 0.001), whereas in the VHA, African American men were not significantly more likely to present with metastatic disease (African-American 3.2% versus White 3.3%, p= 0.26; multivariable OR 1.07, 95% CI 0.98-1.17, p= 0.12). In SEER, the 8-year cumulative incidence of PCSM was significantly higher for African American compared with White men (6.9% versus 5.1%, p< 0.001), whereas in the VHA, African American compared with White men did not have a significantly higher 8-year cumulative incidence of PCSM (5.5% versus 5.4%, p= 0.93). African American race was significantly associated with an increased risk of PCSM in SEER (univariable subdistribution hazard ratio [SHR] 1.39, 95% CI 1.33-1.45, p< 0.001), but was not significantly associated with PCSM on uni- and multivariable regression in the VHA. When adjusted for disease characteristics at diagnosis in SEER, disease extent, PSA, and Gleason score contributed to 85% of the risk of PCSM for African American men (adjusted SHR 1.06, 95% CI 1.02-1.12, p= 0.008). Conclusions: Racial disparities in PCSM were present in a national cohort, SEER, but not as pronounced in a relatively equal-access healthcare system, the VHA, potentially due to differences in metastatic disease at diagnosis among African American and White men between cohorts. These findings may be attributable to reduced barriers to care in the VHA.

Intensive Induction Therapy Compared With CHOP for Hepatosplenic T-cell Lymphoma

INTRODUCTION

Hepatosplenic T-cell lymphoma (HSTCL) is a rare peripheral T-cell lymphoma that disproportionately affects individuals with a clinical history of immunosuppression. It carries a poor prognosis, and, owing to its rarity, there is no single or well-established treatment.

PATIENTS AND METHODS

We conducted the largest-to-date individual-level meta-analysis based on literature searches to determine the best induction therapy for HSTCL. We compared response rates and survival among patients who received "non-CHOP-based" induction with regimens containing cytarabine, etoposide, and/or platinum-based treatment to those receiving treatment with CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone) or CHOP-like therapy. We also review additional regimens including alemtuzumab and pentostatin, and assessed the role of consolidation with hematopoietic stem-cell transplantation (HSCT).

RESULTS

We identified 166 patients with HSTCL, 118 of whom had sufficient information on induction treatment and survival. Eighty-four patients received non-CHOP-based (N = 34) or CHOP/CHOP-like (N = 50) induction treatment. Non-CHOP-based induction was associated with a complete/partial response rate of 82% compared with 52% (P = .006) with CHOP/CHOP-like and increased median overall survival (P = .00014). Our data showed that maximum survival among patients with HSTCL was achieved with non-CHOP-based induction followed by consolidation with HSCT.

CONCLUSIONS

Non-CHOP-based induction appears superior to CHOP/CHOP-like induction in both achieving complete/partial response and durable survival. Induction therapy of HSTCL should be intensified with non-CHOP-based regimens and followed by consolidation with HSCT in eligible patients.

Disparities in knowledge and use of tobacco treatment among smokers in California following healthcare reform

The Affordable Care Act (ACA) promised to narrow smoking disparities by expanding access to healthcare and mandating comprehensive coverage for tobacco treatment starting in 2014. We examined whether two years after ACA implementation disparities in receiving clinician advice to quit and smokers' knowledge and use of treatment resources remained. We conducted telephone interviews in 2016 with a stratified random sample of self-reported smokers newly enrolled in the Kaiser Permanente Northern California's (KPNC) integrated healthcare delivery system in 2014 (N = 491; 50% female; 53% non-white; 6% Spanish language). We used Poisson regression with robust standard errors to test whether sociodemographics, insurance type, comorbidities, smoking status in 2016 (former, light/nondaily [<5 cigarettes per day], daily), and preferred language (English or Spanish) were associated with receiving clinician advice to quit and knowledge and use of tobacco treatment. We included an interaction between smoking status and language to test whether the relation between smoking status and key outcomes varied with preferred language. Overall, 80% of respondents received clinician advice to quit, 84% knew that KPNC offers cessation counseling, 54% knew that cessation pharmacotherapy is free, 54% used pharmacotherapy, and 6% used counseling. In multivariate models, Spanish-speaking light/nondaily smokers had significantly lower rates of all outcomes, while there was no association with other demographic and clinical characteristics. Following ACA implementation, most smokers newly enrolled in KPNC received clinician advice to quit and over half used pharmacotherapy, yet counseling utilization was low. Spanish-language outreach efforts and treatment services are recommended, particularly for adults who are light/nondaily smokers.

Do you vape? Leveraging electronic health records to assess clinician documentation of electronic nicotine delivery system use among adolescents and adults

Use of electronic nicotine delivery systems (ENDS) has increased substantially over the past decade. However, unlike smoking, which is systematically captured by clinicians through routine screening and discrete documentation fields in the electronic health record (EHR), unknown is the extent to which clinicians are documenting patients' use of ENDS. Data were gathered from medical visits with patients aged 12 and older (N=9,119; 55% male) treated in a large, integrated healthcare system. We used natural language processing to assess the incidence rates of clinician documentation of patients' ENDS use in unstructured tobacco comments in the EHR, and the words most frequently documented in relation to ENDS, from 2006-2015. ENDS documentation in the EHR increased dramatically over time (from 0.01 to 9.5 per 10,000 patients, p<0.0001), particularly among adults aged 18-24 and 25-44. Most prevalent were "e-cig," "electronic cigarettes", and "vape," with much variation in spelling and phrasing of these words. Records of adolescent and young adult patients were more likely to contain the word "vape", and less likely to have "e-cig" and "electronic cigarette" than records of adults (ps<0.0001). The relatively low observed number of patients with ENDS terms in the EHR suggested vast under documentation. While healthcare providers are increasingly documenting patients' use of ENDS in the EHR, overall documentation rates remain low. Discrete EHR fields for standard screening and documentation of ENDS that reflect the language used by patients would provide more complete longitudinal population-level surveillance of ENDS use and its association with short- and long-term health outcomes.

Apolipoprotein D expression does not predict breast cancer recurrence among tamoxifen-treated patients

BACKGROUND

Apolipoprotein D (ApoD) has been proposed as a predictor of breast cancer recurrence among estrogen receptor-positive (ER+), tamoxifen-treated patients.

METHODS

We conducted a population-based case-control study nested in a population of 11,251 women aged 35-69 years at diagnosis with Stage I-III breast cancer between 1985 and 2001 on Denmark's Jutland Peninsula and registered with the Danish Breast Cancer Cooperative Group. We identified 541 recurrent or contralateral breast cancers cases among women with ER+ disease treated with tamoxifen for at least 1 year and 300 cases in women with ER- disease never treated with tamoxifen. We matched one control subject per case and assessed ApoD expression in the tumor cell nucleus and cytoplasm using tissue microarray immunohistochemistry. We computed the odds ratio (OR) associating ApoD expression with recurrence and adjusted for potential confounding using logistic regression.

RESULTS

Cytoplasmic ApoD expression was seen in 68% of ER+ tumors, in 66% of ER- tumors, and in 66% of controls across both groups. In women with ER+ tumors, the associations of cytoplasmic ApoD expression with recurrence (OR = 1.0; 95% CI = 0.7 to 1.4) and increasing cytoplasmic expression with recurrence (OR = 1.0; 95% CI = 0.996 to 1.003) were null, as were those for women with ER- tumors. Associations for nuclear ApoD expression and combined nuclear and cytoplasmic expression were similarly near-null.

CONCLUSION

ApoD expression is likely not a predictor of recurrence in tamoxifen-treated patients.

IMPACT

This study eliminates the previously suggested marker ApoD as a predictor of recurrence among tamoxifen-treated women.

X chromosome-wide analysis identifies DNA methylation sites influenced by cigarette smoking

Background

Tobacco smoking is a major cause of chronic disease worldwide. Smoking may induce cellular and molecular changes including epigenetic modification, with both short-term and long-term modification patterns that may contribute to phenotypic expression of diseases. Recent epigenome-wide association studies (EWAS) have identified dozens of smoking-related DNA methylation (DNAm) sites. However, the X chromosomal DNAm sites have been largely overlooked due to a lack of an analytical framework for dealing with the sex-dimorphic distribution. To identify novel smoking-related DNAm sites on the X chromosome, we examined the modality of each X chromosomal DNAm site and conducted a sex-specific association study of cigarette smoking.

Results

We used a discovery sample of 139 middle-age twins, and three replication samples of 78 twins, 464 and 333 unrelated individuals including 47, 17, 22, and 89 current smokers, respectively. After correction for multiple testing, the top smoking-related DNAm sites in BCOR and TSC22D3 were significantly hypermethylated and hypomethylated, respectively, among current smokers. These smoking-associated sites were replicated with meta-analysis p-values of 9.17 × 10⁻¹² and 1.61 × 10⁻⁹. For both sites, the smoking effects on methylation levels were larger in males than that in females.

Conclusions

Our findings highlight the importance of investigating X chromosome methylation patterns and their associations with environmental exposures and disease phenotypes and demonstrate a robust statistical methodology for such study. Existing EWAS of human diseases should incorporate the X chromosomal sites to complete a comprehensive epigenome-wide scan.

Electronic supplementary material

The online version of this article (doi:10.1186/s13148-016-0189-2) contains supplementary material, which is available to authorized users.