Risk Factors for Radiotherapy Failure in the Treatment of Spinal Metastases.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To build a predictive model for risk factors for failure of radiation therapy, hypothesizing a higher SINS would correlate with failure. METHODS: Patients with spinal metastasis being treated with radiation at a tertiary care academic center between September 2014 and October 2018 were identified. The primary outcome measure was radiation therapy failure as defined by persistent pain, need for re-irradiation, or surgical intervention. Risk factors were primary tumor type, Karnofsky and ECOG scores, time to treatment, biologically effective dose (BED) calculations using α/ß ratio = 10, and radiation modality. A logistic regression was used to construct a prediction model for radiation therapy failure. RESULTS: One hundred and seventy patients were included. Median follow up was 91.5 days. Forty-three patients failed radiation therapy. Of those patients, 10 required repeat radiation and 7 underwent surgery. Thirty-six patients reported no pain relief, including some that required re-irradiation and surgery. Total SINS score for those who failed reduction therapy was <7 for 27 patients (62.8%), between 7-12 for 14 patients (32.6%), and >12 for 2 patients (4.6%). In the final prediction model, BED (OR .451 for BED > 43 compared to BED ≤ 43; P = .174), Karnofksy score (OR .736 for every 10 unit increase in Karnofksy score; P = .008), and gender (OR 2.147 for male compared to female; P = .053) are associated with risk of radiation failure (AUC .695). A statistically significant association between SINS score and radiation therapy failure was not found. CONCLUSIONS: In the multivariable model, BED ≤ 43, lower Karnofksy score, and male gender are predictive for radiotherapy failure. SINS score was among the candidate risk factors included in multivariable model building procedure, but it was not selected in the final model. LEVEL OF EVIDENCE: Prognostic level III.

A Multidisciplinary Central Nervous System Clinic Model for Radiation Oncology and Neurosurgery (RADIANS): three-year experience with brain and skull base lesions in a community hospital setting.

BACKGROUND: Subspecialty, multidisciplinary care within community hospital settings are limited and remains a challenge. Improving outcomes for central nervous system (CNS) disease rely on integrated subspecialty care between radiation oncology (RadOnc) and neurosurgery (NS). Three-year experience with simultaneous patient evaluation with RadOnc and NS physicians in a community hospital-based CNS clinic model (RADIANS) for brain and skull base lesions (BSBL) are reported. METHODS: Clinical and demographic data were prospectively collected for patients evaluated in RADIANS. Surveys administered and three-year data reviewed. Descriptive statistics reported as mean and percentages for patient characteristics, diagnosis, treatment and outcomes. RESULTS: Sixty-seven patients with confirmed BSBL were evaluated between August 2016 and August 2019. Mean age and distance traveled was 61.0 years and 66.5 miles, respectively. Female (N.=39, 58.2%) and male (N.=28, 41.8%) patients had mean Patient Satisfaction Score of 4.77 (0-5 Scale, where 5 is very satisfied; 26 respondents). Forty-three patients had malignant disease (28 brain mets; six with both brain/spine; nine with primary brain), and 24 had benign disease. Post-evaluation treatment: radiation therapy (RT) only (N.=16), neurosurgery (NS) only (N.=12), both RT and NS (N.=15), and no RT/NS intervention (N.=24). Fractionated stereotactic radiosurgery was most common RT delivered; craniotomy with tumor resection was most common NS performed. Treatment outcomes: local control in 33 of 38 (86.8%); radiation necrosis in one of 31 (3.2%). CONCLUSIONS: The multidisciplinary community hospital-based CNS clinic continues its high patient approval at extended follow-up. Results demonstrate the clinic serves as a regional referral center where patients with BSBL with varying degrees of co-morbidities, systemic disease status, and oncologic staging can be treated with evidence-based treatment modalities yielding high rates of local control and low rates of grade 3 and 4 radiation-induced toxicity, while having access to on-going clinical trials.

Academic patterns of practice regarding CT simulation scans and radiology review.

OBJECTIVE: Currently, there are no consensus guidelines about handling incidental radiological findings on radiotherapy planning CT simulation scans. Retrospective studies analyzing incidental findings on CT simulations show a small, but not insignificant, rate of both oncologic and non-oncologic findings. These findings may have medico-legal, financial, and clinical implications. Given a lack of guidelines, we obtained a formal survey of multiple academic institutions to evaluate how CT simulations are handled in regard to incidental findings. METHODS: A formal survey was developed consisting of 12 questions related to institutional practices regarding CT simulation scans. From 7/18/21 to 8/27/21 and 5/6/22 to 5/24/22, the survey was administered electronically by REDCap to key personnel at Academic Radiation Oncology Programs identified through the American Society for Radiation Oncology (ASTRO) with inclusion criteria including an active ACGME approved Radiation Oncology residency program. RESULTS: In total, 88 academic radiation oncology programs were surveyed with total of 45 responses (51%). 1 out of 45 departments who responded has formal guidelines regarding workup of incidental findings. There is variability about sending CT simulation scans for official radiology review if an incidental finding is identified. CONCLUSIONS: Based on a measurable rate of incidental findings on radiotherapy planning CT simulations and their possible implications, our survey illustrates a likely need for consensus recommendations for handling such findings to improve patient care and safety.

Navigator-assisted hypofractionation (NAVAH) to address radiation therapy access disparities facing African-Americans with breast cancer.

Background: African-Americans have the highest overall cancer death rate and shortest survival time of any racial or ethnic group in the United States. The most common cancer studied in African-American radiation therapy (RT) access disparities research is breast cancer. The goal of this study is to evaluate the impact of patient navigation on RT access for African-American breast cancer patients. Material and methods: This study is a prospective survey-based evaluation of the impact of patient navigation on access to hypofractionated RT and financial toxicity in African-American breast cancer patients. The impact of patient navigation on RT access will be collated and analyzed from survey results pre-RT versus post-RT as well as for patients with versus without receipt of patient navigation. The validated COST-Functional Assessment of Chronic Illness Therapy score will be used to compare hypofractionation versus standard fractionated RT financial toxicity for patients with early-stage breast cancer who have received lumpectomy. Conclusion: This is the first study to investigate the impact of patient navigation on reducing RT access disparities facing African-American breast cancer patients. The natural progression of this work will be to expand this model to include additional breast cancer populations most vulnerable to suffering RT access disparities (Native American, Hispanic American, Appalachian) within the United States.

An interdisciplinary consensus on the management of brain metastases in patients with renal cell carcinoma.

Brain metastases are a challenging manifestation of renal cell carcinoma. We have a limited understanding of brain metastasis tumor and immune biology, drivers of resistance to systemic treatment, and their overall poor prognosis. Current data support a multimodal treatment strategy with radiation treatment and/or surgery. Nonetheless, the optimal approach for the management of brain metastases from renal cell carcinoma remains unclear. To improve patient care, the authors sought to standardize practical management strategies. They performed an unstructured literature review and elaborated on the current management strategies through an international group of experts from different disciplines assembled via the network of the International Kidney Cancer Coalition. Experts from different disciplines were administered a survey to answer questions related to current challenges and unmet patient needs. On the basis of the integrated approach of literature review and survey study results, the authors built algorithms for the management of single and multiple brain metastases in patients with renal cell carcinoma. The literature review, consensus statements, and algorithms presented in this report can serve as a framework guiding treatment decisions for patients. CA Cancer J Clin. 2022;72:454-489.

Geriatric patient outcomes in a multidisciplinary central nervous system community hospital clinic for radiation oncology and neurosurgery (RADIANS).

INTRODUCTION: Management of older adult patients with central nervous system (CNS) cancers requires a patient-centric, multidisciplinary approach. Assessment of neurosurgical and radiation treatment outcomes can assist in establishing guidelines for this patient population. We previously reported on the RADIANS clinic, a novel community hospital-based multidisciplinary clinic (MDC) for CNS cancer care, providing simultaneous radiation oncology and neurosurgery evaluation in a same-day, single-setting clinic. We now provide a focused analysis of our older adult patient population and recommendations for triage and standardization of care. METHODS: Consecutive older adult patients (age ≥ 65) evaluated at the RADIANS clinic for CNS disease were identified and retrospectively reviewed. Observed 30-day neurosurgical outcomes were compared to predicted outcomes determined by the American College of Physicians NSQIP Surgical Risk Calculator. One-sample binomial exact tests were used to evaluate binary outcome measures. A two-sample t-test was used to evaluate the length of hospital stay. Brier Scores were calculated to assess the deviation between predicted probabilities and observed outcomes for binary outcome measures. Overall survival at 90 days was reported. RESULTS: Fifty-six older adult patients with malignant (42/56) and benign (14/56) CNS disease were evaluated. Mean distance traveled for multidisciplinary evaluation at the RADIANS clinic was 43.4 miles. There was no incidence of radiation-induced toxicity. Mean length of hospital stay for RADIANS patients was significantly shorter by about 1.5 to 3.5 days (95% CI). There was no statistically significant difference for other outcome measures, however, Brier Scores demonstrated that NSQIP was not a good predictive tool for any or serious complications, UTI, venous thromboembolism, return to OR, readmission, or death in our cohort. Local tumor control rate and progression-free survival at 90 days were 97.4% and 76.9%, respectively. CONCLUSIONS: This is the first report of CNS disease outcomes in older adult patients evaluated by radiation oncology and neurosurgery at a community hospital-based MDC. We observed minimal adverse radiation outcomes and high tumor control in our cohort. Findings show significantly shorter postoperative hospital stay for patients evaluated and managed at the RADIANS clinic.

Evolution of the prevalence of pre-residency peer-reviewed publications among incoming junior residents.

Pre-residency peer-reviewed publications (PRP) have been associated with subsequent resident choice of academic versus private practice career. The evolution of PRP prevalence among radiation oncology resident classes has yet to be examined. A list of radiation oncology residents from the graduating classes of 2016 and 2022 were obtained, and PRP was compiled as the number of publications a resident had listed in PubMed as of the end of the calendar year of residency application. Statistical analysis was conducted using Fisher's exact test. Analysis of 163 residents from the 2016 class compared with 195 from the 2022 class revealed that the proportion of residents with zero PRP decreased from 46.6% to 23.6% between the 2016 to 2022 classes (p<0.0001), while that of residents with one PRP increased from 17.8% to 19.0% (p>0.05) and with at least two PRP increased from 35.6% to 57.4% (p<0.0001). Residents with a PhD were more likely to have at least two PRP in each class (p<0.0001). As with the class of 2016, there remained no significant difference in PRP by gender for the class of 2022. Over the past six years, PRP has become more prevalent among incoming radiation oncology residents. Residents in the class of 2016 were 180% less likely than the class of 2022 to have at least one PRP, and 60% less likely to have at least two PRP. These findings are indicative of the increasing pressure on medical students to enter residency with a publication background.

Gender-based analysis of pre-residency research productivity among a current United States radiation oncology resident class.

BACKGROUND: The increasing proportion of women in medicine has not been adequately reflected in the gender distribution of radiation oncology residents. The presence of at least one pre-residency peer-reviewed publication (PRP) has been associated with radiation oncology resident choice of academic over private practice career, with no significant gender difference in the likelihood of having a PRP (McClelland et al., 2017). We sought to pursue a gender-based analysis of PRP productivity in a current junior resident class. METHODS: A list of radiation oncology residents from the graduating class of 2022 (PGY-2 academic year of 2018-2019) was obtained through internet investigation. Research productivity was calculated using PRP number, defined as the number of a resident's publications listed in PubMed (pubmed.gov) through the calendar year of residency application (2016 for this class). RESULTS: Of 195 residents examined from the 2022 class, 61 (31%) were women, representing a nine percent increase from the resident class of 2016. Four-fifths of women had 1+ PRP, 31% had dual degrees, and 18% had a PhD. These percentages were comparable to their male counterparts, 73% with 1+ PRP, 28% with dual degrees, and 15% with a PhD. There were no statistically significant differences by gender in any of these benchmarks. CONCLUSIONS: While slower than the overall trend of increased female representation in medicine, the proportion of women in radiation oncology residency has increased by 0.9-1.5% annually over a recent six-year span. There remain no significant differences in PRP productivity, dual degree status, or PhD status by gender.

Impact of hospital volume on mortality for brain metastases treated with radiation.

BACKGROUND: The impact of hospital volume on cancer patient survival has been demonstrated in the surgical literature, but sparsely for patients receiving radiation therapy (RT). This analysis addresses the impact of hospital volume on patients receiving RT for the most common central nervous system tumor: brain metastases. MATERIALS AND METHODS: Analysis was conducted using the National Cancer Database (NCDB) from 2010-2015 for patients with metastatic brain disease from lung cancer, breast cancer, and colorectal cancer requiring RT. Hospital volume was stratified as high-volume (≥ 12 brain RT/year), moderate (5-11 RT/year), and low (< 5 RT/year). The effect of hospital volume on overall survival was assessed using a multivariable Cox regression model. RESULTS: A total of 18,841 patients [9479 (50.3%) men, 9362 (49.7%) women; median age 64 years] met the inclusion criteria. 16.7% were treated at high-volume hospitals, 36.5% at moderate-volume, and the remaining 46.8% at low-volume centers. Multivariable analysis revealed that mortality was significantly improved in high-volume centers (HR: 0.95, p = 0.039) compared with low-volume centers after accounting for multiple demographics including age, sex, race, insurance status, income, facility type, Charlson-Deyo score and receipt of palliative care. CONCLUSION: Hospitals performing 12 or more brain RT procedures per year have significantly improved survival in brain metastases patients receiving radiation as compared to lower volume hospitals. This finding, independent of additional demographics, indicates that the increased experience associated with increased volume may improve survival in this patient population.

Relevance of circulating hybrid cells as a non-invasive biomarker for myriad solid tumors.

Metastatic progression defines the final stages of tumor evolution and underlies the majority of cancer-related deaths. The heterogeneity in disseminated tumor cell populations capable of seeding and growing in distant organ sites contributes to the development of treatment resistant disease. We recently reported the identification of a novel tumor-derived cell population, circulating hybrid cells (CHCs), harboring attributes from both macrophages and neoplastic cells, including functional characteristics important to metastatic spread. These disseminated hybrids outnumber conventionally defined circulating tumor cells (CTCs) in cancer patients. It is unknown if CHCs represent a generalized cancer mechanism for cell dissemination, or if this population is relevant to the metastatic cascade. Herein, we detect CHCs in the peripheral blood of patients with cancer in myriad disease sites encompassing epithelial and non-epithelial malignancies. Further, we demonstrate that in vivo-derived hybrid cells harbor tumor-initiating capacity in murine cancer models and that CHCs from human breast cancer patients express stem cell antigens, features consistent with the potential to seed and grow at metastatic sites. Finally, we reveal heterogeneity of CHC phenotypes reflect key tumor features, including oncogenic mutations and functional protein expression. Importantly, this novel population of disseminated neoplastic cells opens a new area in cancer biology and renewed opportunity for battling metastatic disease.

Three-Year Experience of a Multidisciplinary Central Nervous System Clinic Model for Radiation Oncology and Neurosurgery (RADIANS) in a Community Hospital Setting.

BACKGROUND: As academic centers partner and establish healthcare systems with community hospitals, delivery of subspecialty, multidisciplinary care in community hospital settings remains a challenge. Improving outcomes for central nervous system (CNS) disease is related to integrated care between neurosurgery (NS) and radiation oncology (RadOnc) specialties. Our multidisciplinary community hospital-based clinic, RADIANS, previously reported high patient approval of simultaneous evaluation with NS and RadOnc physicians. Three-year experience is now reported. METHODS: Prospectively collected clinical and demographic patient data over three years was done, and surveys administered. Descriptive statistics reported as mean and percentages for patient characteristics, diagnosis, treatment and outcomes. RESULTS: Between August 2016 and August 2019, 101 patients were evaluated. Mean age and distanced traveled was 61.2 years, and 54.9 miles, respectively. Patient Satisfaction Score was 4.79 (0-5 Scale, 5-very satisfied). Most common referral source was medical oncologists. Seventy-two patients had malignant CNS disease (brain mets 28; spine mets 27; both 6; primary brain 9; primary spine 2), 29 had benign CNS disease. Post-evaluation treatment: radiation therapy (RT) only (n=29), neurosurgery (NS) only (n=16), both RT and NS (n=22), and no RT/NS intervention (n=34). Fractionated stereotactic radiosurgery was most common RT delivered; craniotomy with tumor resection was most common NS performed. Treatment outcomes: local control=61/67 (91%); radiation necrosis or radiation-induced myelitis=2/51 (3.9%). CONCLUSIONS: The RADIANS multidisciplinary community hospital-based CNS clinic model is first of its kind to be reported, continuing strong patient approval at extended follow-up. Data indicates the model serves as a regional referral center, delivering evidence-based treatment modalities for complex CNS disease in community hospital settings, yielding high rates of local control and low rates of grade 3 or 4 radiation-induced toxicity.

A National Cancer Database analysis of the patterns of care for meningeal melanocytoma.

Aim: To evaluate demographics, treatment patterns, radiotherapy utilization and patient outcomes in meningeal melanocytomas. Materials & methods: The National Cancer Database was queried for meningeal melanocytomas diagnosed in 2002-2016. The effects of demographic, clinical and treatment variables were determined via Kaplan-Meier log-rank and Cox regression analyses. Results: The median and 5-year overall survival were 57.46 months and 48%, respectively. Patients earning ≥$48K showed improved survival (p = 0.0319). Radiotherapy and chemotherapy were utilized in 37.7 and 9% of patients, respectively. Conclusion: Income significantly affected survival. Surgery remains the mainstay approach. Radiotherapy was delivered in more than one-third of patients but did not impact survival. However, further analyses were limited by poor treatment modality information in the database.

Lay abstract Aim: To assess the impact of demographic, clinical and treatment factors on survival in patients with meningeal melanocytomas. Materials & methods: Biostatistical analyses were conducted on patients diagnosed with meningeal melanocytomas between 2002 and 2016 using data from the National Cancer Database. Results: The median and 5-year survival rate were 57.46 months and 48%, respectively. Patients with incomes ≥$48K showed improved survival (p = 0.0319). Radiotherapy and chemotherapy were administered in 37.7 and 9% of patients, respectively. Conclusion: Income was a critical factor in increasing patient survival. Surgery serves as the primary means for treatment, while radiotherapy and chemotherapy remain underutilized.

Resolution of Radiation-Induced Necrosis in Arteriovenous Malformation with Bevacizumab: A Case Report and Review of Current Literature.

Stereotactic radiosurgery (SRS) is a proven treatment modality for inoperable arteriovenous malformations (AVMs). However, the rate of radiation-induced necrosis (RIN) is as high as 10%. A 6-year-old female patient presented with severe headache, emesis, and syncope, and workup revealed a Spetzler-Martin grade 4 AVM with intraventricular hemorrhage and hydrocephalus. The patient underwent a right frontal ventriculostomy followed by a linear accelerator-based SRS of 16.9 Gy. At 19 years, she developed progressive neurological symptoms. Diagnostic magnetic resonance imaging (MRI) revealed a recurrent parietal AVM nidus. We delivered the linear accelerator-based SRS of 18.5 Gy to the AVM nidus. Within 9 months, she experienced episodic headaches and left-sided weakness and spasticity; symptoms were initially managed with dexamethasone. Follow-up MRI was notable for edema and nondetectable blood flow, consistent with RIN and AVM obliteration. The second course of steroids did not provide the symptom control. Persistent RIN was noted on MRI, and she had stigmata of steroid toxicity (centripetal obesity, depression, and sleep disorder). Two infusions of bevacizumab (5 mg/kg) were administered concurrently with a tapering dose of dexamethasone. The patient noted a near immediate improvement in her headaches, and 2 months following the second bevacizumab infusion, she reported a near-complete resolution of her symptoms and displayed improved ambulation. The development of RIN remains a noteworthy concern post-SRS of AVMs. While steroids aid with initial management of RIN, for persistent and recurrent symptoms, bevacizumab infusions serve as a viable treatment course, with the added benefit of reducing the likelihood of adverse effects resulting from prolonged steroid therapy.

Cost-Effectiveness of Stereotactic Radiosurgery and Stereotactic Body Radiation Therapy in Treating Brain Metastases.

Single-fraction stereotactic radiosurgery (SRS) is a highly used tool in managing brain metastases, alongside its multifraction counterpart - stereotactic body radiation therapy (SBRT). These radiation therapy techniques have been associated with excellent clinical outcomes, such as decreased local recurrence, increased survival, and improved palliative effects. However, present literature concerning the cost-effectiveness of these techniques remain scarce. Based on the current procedure terminology codes involving services provided during radiation consultation, treatment, and follow-up in our institution, 3-fraction SBRT with a 3-dimensional plan and intensity modulated radiation therapy cost 27% and 17% more than SRS, respectively. A 32% and 34% price increase can, respectively, be seen in 5-fraction SBRT with 3-dimensional plan and intensity modulated radiation therapy delivery sessions relative to 3-fraction SBRT administration. Cost savings between these procedures were associated with the radiation therapy delivery sessions instead of the treatment planning process. These analyses indicate that SRS appears to be a less expensive and time-intensive option than SBRT in our institution. However, additional comparative analyses regarding SRS and SBRT are needed to explore the clinical and financial benefits of these radiation therapy techniques.

Pediatric Pleomorphic Xanthoastrocytoma: A National Database Inquiry on Current Treatment Approaches in the United States.

BACKGROUND: Pleomorphic xanthoastrocytomas (PXAs) account for <1% of primary brain tumors, occurring predominantly in children and young adults. Surgical resection serves as the primary treatment for PXAs, while radiotherapy (RT) and chemotherapy protocols remain poorly defined. AIM: This study aims to determine current care patterns utilized for pediatric patients (≤ 18 years) diagnosed with PXAs and their effect on overall survival. METHODS: The United States National Cancer Database (NCDB) was queried between 2004 and 2015 for pediatric patients (≤18 years) diagnosed with PXAs. RESULTS: From the 224 qualifying patients, most patients proceeded with surgery only (78.1%), while 11.6% of patients received both adjuvant RT and chemotherapy. In the 2010-2015 cohort, patients with subtotal resection were associated with poorer prognosis than those with gross-total resection (hazard ratio = 17.44, 95% confidence interval = 2.10-144.90, p < .001). RT and chemotherapy recipients were similarly associated with poorer survival than those treated with surgery only, with p-values of <.001 and respective hazard ratios of 3.82 (95% confidence interval = 1.85-7.90) and 6.68 (95% confidence interval = 3.21-13.89). The key factors impacting the probability of RT delivery involved WHO grade (p < .001) and chemotherapy administration (p < .001). However, WHO grade alone did not significantly impact survival (p-value = .088). CONCLUSION: Maximally safe resection is the current treatment goal for patients with PXAs. RT and chemotherapy are poorly utilized but had a greater role in managing more aggressive cases of PXAs. Additional research focusing on the impact of adjuvant therapies on tumor progression is needed to better guide treatment decisions.

Disparities in Patterns of Conventional Versus Stereotactic Body Radiotherapy in the Treatment of Spine Metastasis in the United States.

INTRODUCTION: The improved survival of patients even with metastatic cancer has led to an increase in the incidence of spine metastases, suggesting the need for a more aggressive palliative treatment than conventional external beam radiation therapy (cEBRT). Consequently, spinal stereotactic body radiation therapy (SBRT) has increased in popularity over the past decade. However, there has been no comparison of patterns of usage of cEBRT versus SBRT in the treatment of spinal metastases in the US. METHODS: The National Cancer Data Base (NCDB) from 2004-2013 was used for analysis. cEBRT was defined as 30 Gy in 10 fractions, 20 Gy in 5 fractions, or 8 Gy in 1 fraction. SBRT was defined as 25-32 Gy infive5 fractions, 24-32 Gy in 4 fractions, 20-32 Gy in three fractions, 14-32 Gy in 2 fractions, or 14-24 Gy in 1 fraction. Single and multivariable associations between patient demographic and cancer characteristics and type of radiation were performed. RESULTS: From 2004-2013, 23,181 patients with spinal metastases in the United States received cEBRT, while 1,030 received SBRT as part of their first course of treatment. Most patients (88%) received 10 fractions of radiation. Multivariable analysis suggested that non-Medicare or private insurance (adjusted OR 0.4-0.7), African-American race (adjusted OR = 0.8, 95%CI = 0.7-1.0), age 65+ (adjusted OR = 0.8), living in a region with lower population (adjusted OR 0.7), earlier year of diagnosis (OR = 0.9), and receiving treatment in a non-academic/research facility (adjusted OR 0.6) were associated with cEBRT. After controlling for other variables, regional education level was no longer significantly associated with cEBRT. CONCLUSIONS: Most patients with spine metastases were treated with cEBRT, usually with 10 fractions. Receipt of SBRT was significantly associated with race, insurance, geography, population, type of treatment facility, and year of diagnosis, even after controlling for other factors. These findings raise questions about disparities in access to and delivery of care that deserve further investigation.