An Update on the Management of Bone Metastases

PURPOSE OF REVIEW

Increasing life expectancy among patients with advanced cancer has placed a greater emphasis on optimizing pain control and quality of life. Concurrently, significant advancements in radiotherapy for bone metastases have permitted for dose escalation strategies such as stereotactic radiotherapy. This review aims to provide updated information on the management of bone metastases in light of these developments.

RECENT FINDINGS

We reviewed recent studies regarding the role and details of external beam radiotherapy for bone metastases, with emphasis on differences by treatment site as well as intention (palliative versus ablative for oligometastases). Conventional palliative radiotherapy remains a mainstay of management. While stereotactic radiotherapy may augment durability of pain relief and even survival time, there are significant questions remaining regarding optimal dosing and patient selection. Radiotherapy for bone metastases continues to evolve, particularly with increasing use of stereotactic radiotherapy. Future studies are needed to clarify optimal dose, fractionation, modality, and patient selection criteria among different radiotherapy approaches.

Stereotactic Radiotherapy Deserts are Under-Represented among Radiation Oncology Alternative Payment Model Sites

PURPOSE/OBJECTIVE(S)

In bundled payment models including the proposed Radiation Oncology Alternative Payment Model (RO-APM), reimbursement favors shorter treatment paradigms like stereotactic radiotherapy (SRT). However, SRT requires specialized equipment, staff, and quality assurance procedures not available across the US. To understand the geospatial distribution of SRT and its impact on bundled payment models, we investigated the interplay between SRT resources with sociodemographic characteristics and oncologic outcomes for an index site of prostate cancer (PC).

MATERIALS/METHODS

We constructed an ecologic study model using data from the HRSA Area Health Resources, AMA Physician Masterfile, USDA Agriculture Economic Research Service, Medicare Provider and Service Files, and NIH Cancer State Profiles. SRT use was operationalized as the presence of Medicare SRT billing codes. Sociodemographic variables included county racial distributions, %poverty, and rural vs. urban classification. Provider to patient at risk density (PPRD) was defined as number of radiation oncologists per 100,000 males ≥65 years. PC incidence and death rates were evaluated. Uni- and multivariable logistic regressions examined links between SRT use, proposed RO-APM status, PPRD, sociodemographic variables, and PC oncologic outcomes at the US county level. All listed statistics demonstrated p <0.05.

RESULTS

SRT use was identified in 13% of all 3140 counties and in 49% of counties with documented RO providers. In univariable analyses, odds of SRT use was higher in counties that were metro [odds ratio (OR) 19.9] and with higher %Black constituents (OR 6.95); odds decreased with higher %poverty (OR 0.92). Among counties with RO providers, odds of SRT use increased with higher PPRD (OR 1.01). Odds of SRT use was associated with higher PC incidence (1.01) but lower death rates (OR 0.99). SRT use was more common in participating RO-APM counties (OR 2.66); moreover, magnitude and direction of associations between sociodemographic variables and RO-APM participation were similar to those for SRT use. In multivariable analysis, SRT use remained significantly associated with metro status, %Black constituents, PPRD, and PC death rates.

CONCLUSION

Both SRT use and proposed RO-APM participation were most prevalent in metro counties with higher PPRD and %Black populations, likely reflecting presence of densely populated cities with high health resources. If SRT is incentivized in future reimbursement models, then rural, lower resource communities without SRT may be disadvantaged. Lack of association between SRT and PC incidence indicates the presence of "SRT deserts"-counties with high oncologic need but no SRT. To enable visualization of SRT deserts and encourage interventions aimed at reducing disparities in SRT access, our results will be included in an interactive web platform (bit.ly/density maps).

Prospective and Comprehensive Characterization of an Inpatient Radiation Oncology Consult Service: Examining Interdisciplinary Coordination of Palliative Radiation Access and Receipt

PURPOSE/OBJECTIVE(S)

Studies have increasingly demonstrated the benefit of dedicated palliative radiation therapy (PRT) models on care quality, coordination and cost-effectiveness. However, these studies are primarily retrospective and volume-based, limiting broad application of findings. Through prospective, comprehensive characterization of inpatient consults, we investigated trends in interdisciplinary coordination and PRT delivery.

MATERIALS/METHODS

Inpatient consult pages at a single institution from 11/1/21-5/31/22 were prospectively tracked and characterized. Consult type, temporality and decision-making, and patient demographics, disease and treatment details, and mortality outcomes were recorded. Chi-square and logistic and linear regressions evaluated associations between consult and patient-specific features.

RESULTS

Of 460 pages received, 131 (28.5%) were requests for further communication following initial consultation. For the 329 original consults, 20.1% related to care coordination for established on-treatment or recently treated patients who were hospitalized. RT was recommended for 57% of patients-81.3% with palliative intent. With a mean 1.85 vs. 0.8 consults per day for weekday vs. weekend, 52.6% and 34.0% of pages occurred from 7am-noon or noon-5pm respectively, with 13.4% received overnight. This distribution did not significantly differ between weekday vs. weekend. Consult type (RT consideration vs. care coordination) was not associated with day or time period. Concern regarding benefit and/or safety of radiation was the main reason for treatment deferral (31.3%). Neurologic compromise (38.7%), pain (33.8%) and obstruction (ex. airway, luminal; 11.6%) were the most frequent non-post-operative palliative indications. Median time from admission to consult was 2 days (range 0-70), with a median of 1 day for neurologic compromise, 2 days for pain and 4 days for obstruction. For PRT scenarios, patients treated or untreated with RT had no significant difference in 30 days (25.2% vs. 28.2%, respectively) or 60 days (39.6% vs. 46.3%, respectively) mortality. 53.5% of patients had either a palliative medicine consultation while an inpatient or one scheduled at the time of discharge.

CONCLUSION

Prospective characterization at a tertiary-care institution reveals high-volume care coordination- and communication-related consults with temporal distribution similar to consults for RT consideration for new patients. Association of timing with palliative indication and the observed rate of palliative medicine involvement highlight opportunities for interdisciplinary education regarding early multidisciplinary engagement to ensure provision of comprehensive palliative oncologic care.

Health Equity Achievement in Radiation Therapy (HEART) Score: A Social Prognosis

PURPOSE/OBJECTIVE(S)

The aim of this study was to develop a Health Equity Achievement in Radiation Therapy (HEART) score that can help identify patients at risk of experiencing suboptimal quality-of-care (QoC) early on in the patient-provider encounter and prior to initiation of treatment. Such a score may improve shared decision making to improve QoC.

MATERIALS/METHODS

A retrospective analysis was conducted using the National Cancer Database (NCDB) for prostate cancer cases between 2004-2017. Sociodemographic factors, clinical characteristics, and treatment information were collected. A composite HEART score was built to predict suboptimal QoC, defined as treatment refusal, incomplete treatment, or treatment delay. 70% of the data was allocated to training and 30% to validating a logistic regression model through which a nomogram was constructed.

RESULTS

A total of 1,599,785 patients were included in the analysis, of whom 126,917 (7.9%) had at least one suboptimal QoC. The strongest predictors were Black race, uninsured status, lower educational status, geographic location, and nodal disease (Table). The nomogram demonstrated a fair ability to predict quality metrics, with an area under the receiver operating characteristic curve (AUC) of 0.57 in the test group. The nomogram facilitated graphic interpretation of systemic factors in contributing to suboptimal QoC.

CONCLUSION

With observed potential for predicting suboptimal QoC outcomes in patients with prostate cancer by considering systemic barriers, this NCDB-based nomogram has potential utility as a tool for identifying patients who may benefit from additional social support, including the financial resources associated with these services, to improve access to care. Further validation in diverse datasets is needed to improve performance and generalizability to broader patient populations and different disease sites.

Impact of the Affordable Care Act on Pediatric Proton Radiation Therapy Access

PURPOSE/OBJECTIVE(S)

Previous work has demonstrated that socioeconomic factors affect the use of PT in children1. Medicaid expansion came into effect in 2014. In 2014, there were 15 proton centers in the US, which increased to 31 by 20202. The effects of increased PT center number and expansion of insurance coverage on PT access has yet to be investigated.

MATERIALS/METHODS

This was an observational cohort study using the National Cancer Database (NCDB) to assess for changes in utilization of PT for pediatric cancers before and after Medicaid expansion. Demographics and characteristics were summarized with one-way analysis of variance for continuous variables and χ2 for categorical variables. Data regarding geography of treated patients was suppressed. Logistic regression was performed to investigate the effect of SES and insurance on treatment type. All p values are two-sided, with a significance level of 0.05 used. Statistical analyses were performed in R (version 4.1.2).

RESULTS

There were 17,096 patients diagnosed at ages ≤21 years from 2004-2020 treated with either photon or PT with known insurance status. 14,491 patients were treated with photons; 2,605 patients received PT. The number of uninsured patients dropped after 2014 from 3.5% to 2.0%, p<0.001. The number of patients with Medicaid who received PT increased after 2014 (21.9% to 28.5%, p<0.001). From 2004-2020, PT increased from 0.4% to 12.4%, peaking in 2018 at 13.9%. Patients with private insurance had higher odds (OR1.5, CI 1.28-1.65) of PT compared to those with Medicaid when controlling for the increased likelihood of PT over time. Patients of higher SES had a higher likelihood of getting treated with PT both before and after Medicaid expansion, while those of the lowest quartile SES did not witness a significant change in the proportion of patients being treated with PT, (11.5% to 12.1% after 2014). Utilization based on race did not significantly change after 2014 among White, Black, and Asian/Pacific Islander populations, but did decrease for patients who identified as Spanish/Hispanic origin (16.9% to 15.0%, p<0.001), and American Indians from 0.7 to 1.3% (p<0.001).

CONCLUSION

Despite the benefits of Medicaid expansion from the ACA since 2014, pediatric patients of Black race and Hispanic ethnicity failed to experience improved access to PT. Pediatric patients with private insurance continued to be more likely to receive PT than patients on Medicaid. Investigation by geography, as well as tumor type, is necessary to provide essential data for creating effective policies to increase equitable access to PT.

Adjuvant treatment decisions among adults aged 65 years and older with early-stage hormone receptor positive breast cancer seen in a simple multidisciplinary clinic versus standard consultation

INTRODUCTION

Randomized studies support de-escalation of adjuvant therapy for a target population of older adults ≥65 years with stage I, estrogen-receptor (ER) positive breast cancer after breast conserving surgery. We sought to evaluate the impact of a simplified multidisciplinary clinic (s-MDC) in this population by comparing treatment patterns and patient perceptions of adjuvant radiation therapy (RT) and hormone therapy (HT) between patients seen in s-MDC vs. standard consultations.

MATERIALS AND METHODS

Medical records were retrospectively reviewed for patients in the above target population who underwent surgery between August 2020 and May 2022 at our institution. Two cohorts were included: (1) patients seen in s-MDC, and (2) patients seen in standard clinic separately by medical and radiation oncology (non-s-MDC cohort). The non-s-MDC patients declined, could not attend, and/or were not referred to the s-MDC. Patients in the s-MDC cohort were prospectively administered validated questionnaires to evaluate patient reported data including the Decision Autonomy Preference Scale (DAPS), e-Prognosis, and Medical Maximizing-Minimizing Scale (MMS). Chi square, t-tests, and non-parametric equivalents compared demographics, and logistic regression evaluated RT and HT use and survey score outcomes between cohorts.

RESULTS

A total of 127 patients met inclusion criteria, with 33 s-MDC and 94 non-s-MDC patients. There was no difference between the cohorts in age, margin status, histology, grade, or focality. In the s-MDC cohort there were significantly more patients without sentinel lymph node biopsy (71.3% vs 42.4%, p = 0.003) and mean tumor size was smaller (0.69 vs. 0.96 cm, p < 0.003), and Charlson comborbidity index (CCI) was higher (5.21 vs 4.96, p = 0.038). There was no significant difference in receipt of RT (65% s-MDC vs 77% standard; odds ratio [OR] = 0.55, p = 0.189), HT (78% ss-MDC vs 72% standard; OR = 1.36, p = 0.513), or both (50% s-MDC vs 59% standard; OR = 0.7, p = 0.429). The s-MDC cohort was significantly more likely to undergo accelerated (vs. standard hypofractionated) RT (70% vs 39%; OR = 3.59, p = 0.020). In s-MDC patients with completed questionnaires (n = 33), all whose selected "mostly patient (n=6)" based decision making by DAPS chose RT while all "mostly doctor (n=1)" chose no RT. Based on e-Prognosis, there were lower odds of RT for increasing Schonberg score/ higher 10 yr mortality risk (OR 0.600, p = 0.048). MMS score ≥ 40 ("maximizer") was strongly linked with the use of RT (OR 18.57, p = 0.011).

DISCUSSION

For adults ≥65 years with early stage, ER positive breast cancer, s-MDC participation was not significantly associated with lower use of adjuvant RT or HT versus standard consultation but was significantly associated with shorter RT courses. DAPS and MMS results indicate that patient treatment preference may be predictable, highlighting an opportunity to tailor consultation discussions and recommendations based on intrinsic patient preferences and individual goals.

Radiotherapy Deserts: Impact of Race, Poverty and the Rural-Urban Continuum on Density of Providers and Utilization of Radiotherapy in the United States

PURPOSE

Prior efforts to characterize disparities in radiotherapy access and receipt have not comprehensively investigated interplay between race, socioeconomic status, and geography relative to oncologic outcomes. We sought to define these complex relationships at the US county level for prostate (PC) and invasive breast (BC) cancer in order to build a tool that facilitates identification of "radiotherapy deserts"-regions with mismatch between radiotherapy resources and oncologic need.

METHODS

We constructed an ecologic study model using national databases to evaluate 3141 US counties. Radiotherapy resources and utilization densities were operationalized as physician (PPR) and utilization (UPR) per person at risk: number of attending radiation oncologists and Medicare beneficiaries per 100,000 persons at risk, respectively. Oncologic need was defined by "hot zone" counties with ≥2 standard deviations (SD) above mean incidence and death rates. Uni- and multivariable logistic regressions examined links between PPR and UPR densities, epidemiologic variables, and hot zones for oncologic outcomes. Reported statistics are p<.05.

RESULTS

Mean (SD) PPR and UPR densities were 2.1 (5.9) and 192.6 (557.6) for PC and 1.9 (5.3) and 174.4 (501.0) for BC, respectively. Counties with high PPR and UPR densities were predominately Metro [odds ratio (OR) 2.9-4.4], generally with higher %Black Non-Hispanic population (OR 1.5-2.3). Incidence and death rate hot zones were largely Non-Metro (OR 0.3-0.6), generally with higher %Black Non-Hispanic constituents (OR 3.2-6.3). Lower PPR density was associated with death rate hot zones for both cancers (OR 0.8-0.9); UPR density was generally not linked to oncologic outcomes on multivariable analysis.

CONCLUSIONS

Mismatch between oncologic need with PPR and UPR disproportionately affects Non-Metro communities with higher %Black Non-Hispanic population. We developed an interactive web platform (bit.ly/densitymaps) to visualize "radiotherapy deserts" and drive targeted investigation of underlying barriers to care in areas of highest need, with the goal of reducing health inequities in this context.

Evaluation of the Clinical Utility of the Bone Metastases Ensemble Trees for Survival Decision Support Platform (BMETS-DSP): A Case-Based Pilot Assessment

PURPOSE

The Bone Metastases Ensemble Trees for Survival Decision Support Platform (BMETS-DSP) provides patient-specific survival predictions and evidence-based recommendations to guide multidisciplinary management for symptomatic bone metastases. We assessed the clinical utility of the BMETS-DSP through a pilot prepost design in a simulated clinical environment.

METHODS

Ten Radiation Oncology physicians reviewed 55 patient cases at two time points: without and then with the use of BMETS-DSP. Assessment included 12-month survival estimate, confidence in and likelihood of sharing estimates with patients, and recommendations for open surgery, systemic therapy, hospice referral, and radiotherapy (RT) regimen. Paired statistics compared pre- versus post-DSP outcomes. Reported statistical significance is P < .05.

RESULTS

Pre- versus post-DSP, overestimation of true minus estimated survival time was significantly reduced (mean difference -2.1 [standard deviation 4.1] v -1 month [standard deviation 3.5]). Prediction accuracy was significantly improved at cut points of < 3 (72 v 79%), ≤ 6 (64 v 71%), and ≥ 12 months (70 v 81%). Median ratings of confidence in and likelihood of sharing prognosis significantly increased. Significantly greater concordance was seen in matching use of 1-fraction RT with the true survival < 3 months (70 v 76%) and < 10-fraction RT with the true survival < 12 months (55 v 62%) and appropriate use of open surgery (47% v 53%), without significant changes in selection of hospice referral or systemic therapy.

CONCLUSION

This pilot study demonstrates that BMETS-DSP significantly improved physician survival estimation accuracy, prognostic confidence, likelihood of sharing prognosis, and use of prognosis-appropriate RT regimens in the care of symptomatic bone metastases, supporting future multi-institutional validation of the platform.

Risk of Malignant Transformation of Giant Cell Tumors of Bone Is 8 Times Lower with Megavoltage vs. Orthovoltage Radiation Therapy

Background

The first-line treatment for most giant cell tumors (GCTs) of bone is surgical; radiotherapy (RT) is reserved for inoperable or refractory cases. While RT techniques have undergone a dramatic change over the past few decades, with the higher energy megavoltage RT replacing orthovoltage RT, concerns for high rates of malignant transformation following RT have limited its use. Evidence suggests a lower incidence of secondary malignancy after treatment with megavoltage compared with orthovoltage RT, but this has not been studied in GCTs. Our main purpose was to compare the incidence of malignant transformation of GCTB between patients treated with orthovoltage vs. megavoltage RT.

Methods

A literature review was performed to identify studies reporting GCTBs treated with RT from 01/1900 through 12/2019. Studies that did not report RT modality or separate orthovoltage and megavoltage results were excluded. Included in the analysis were 6 patients from our institution. Primary outcome was the incidence of malignant transformation; secondary outcomes were time to transformation and incidence of local recurrence. Fisher's exact tests and independent sample t-tests were used, and significance was set at p < 0.05.

Results

Twenty-two studies were included, which reported on 168 GCTBs treated with orthovoltage and 393 treated with megavoltage RT. Transformation incidence was 14% (n = 24) for orthovoltage and 1.8% (n = 7) for megavoltage RT, an 8-fold difference (odds ratio (OR) 9.1, 95% confidence interval (CI) 3.9-22, p < 0.001). Mean time to transformation was 8.7 years for orthovoltage and 11.2 years for megavoltage RT (p=0.28). Incidence of local recurrence was 38% (63/167) for orthovoltage and 17% (66/393) for megavoltage RT (OR 3.3, 95% CI 2.0-4.6, p < 0.001).

Conclusions

The risk of developing a malignancy after RT of GCTB is 8 times lower with megavoltage than with orthovoltage. Malignant transformation with megavoltage, while not zero, is lower than that in historical series. Use of modern RT techniques in inoperable or refractory GCTB may be appropriate.

Improving Quality Metrics in Radiation Oncology: Implementation of Pretreatment Peer Review for Stereotactic Body Radiation Therapy in Patients with Thoracic Cancer

Purpose

Traditional peer reviews occur weekly, and can take place up to 1 week after the start of treatment. The American Society for Radiation Oncology peer-review white paper identified stereotactic body radiation therapy (SBRT) as a high priority for contour/plan review before the start of treatment, considering both the rapid-dose falloff and short treatment course. Yet, peer-review goals for SBRT must also balance physician time demands and the desire to avoid routine treatment delays that would occur in the setting of a 100% pretreatment (pre-Tx) review compliance requirement or prolonging the standard treatment planning timeline. Herein, we report on our pilot experience of a pre-Tx peer review of thoracic SBRT cases.

Methods and Materials

From March 2020 to August 2021, patients undergoing thoracic SBRT were identified for pre-Tx review, and placed on a quality checklist. We implemented twice-weekly meetings for detailed pre-Tx review of organ-at-risk/target contours and dose constraints in the treatment planning system for SBRT cases. Our quality metric goal was to peer review ≥90% of SBRT cases before exceeding 25% of the dose delivered. We used a statistical process control chart with sigma limits (ie, standard deviations [SDs]) to access compliance rates with pre-Tx review implementation.

Results

We identified 252 patients treated with SBRT to 294 lung nodules. When comparing pre-Tx review completion from initial rollout to full implementation, our rates improved from 19% to 79% (ie, from 1 sigma limit [SDs]) below to >2 sigma limits (SDs) above. Additionally, early completion of any form of contour/plan review (defined as any pre-Tx or standard review completed before exceeding 25% of the dose delivered) increased from 67% to 85% (March 2020-November 2020) to 76% to 94% (December 2020-August 2021).

Conclusions

We successfully implemented a sustainable workflow for detailed pre-Tx contour/plan review for thoracic SBRT cases in the context of twice-weekly disease site-specific peer-review meetings. We reached our quality improvement objective to peer review ≥90% of SBRT cases before exceeding 25% of the dose delivered. This process was feasible to conduct in an integrated network of sites across our system.

Improving providers' survival estimates and selection of prognosis- and guidelines-appropriate treatment for patients with symptomatic bone metastases: Development of the Bone Metastases Ensemble Trees for Survival Decision Support Platform

RATIONALE, AIMS AND OBJECTIVES

In the management of symptomatic bone metastases, current practice guidelines do not provide clear methodology for selecting palliative radiotherapy (RT) regimens based on specific patient and disease features. Decision support aids may offer an effective means for translating the complex data needed to render individualised treatment decisions, yet no such tools are available for use in this setting. Thus, we describe the development of the Bone Metastases Ensemble Trees for Survival-Decision Support Platform (BMETS-DSP), which aims to optimise selection of evidence-based, individualised palliative RT regimens.

METHOD

The Ottawa Decision Support Framework was used as the theoretical basis for development of BMETS-DSP. First, we utilised stakeholder input and review of the literature to assess determinants underlying the provider decision. Based on this assessment and iterative stakeholder feedback, we developed the web-based, provider-facing BMETS-DSP. Consistent with the underlying theoretical framework, our design also included assessment of decision quality using the International Patient Decision Aids Standards (IPDAS) certification checklist.

RESULTS

Stakeholder input and review of 54 evidence-based publications identified the following determinants of the provider decision: estimated prognosis, characteristics of the target symptomatic lesion and the primary cancer type, consideration of alternative interventions, access to patient-specific recommendations, and patient preferences. Based on these determinants, we developed the BMETS-DSP that (1) collects patient-specific data, (2) displays an individualised predicted survival curve, and (3) provides case-specific, evidence-based recommendations regarding RT, open surgery, systemic therapy, and hospice referral to aid in the decision-making process. The finalised tool met IPDAS quality requirements. Preliminary results of a pilot assessment suggest impact of clinical outcomes.

CONCLUSIONS

We describe the successful development of a provider-facing decision support platform to aid in the provision of palliative RT in better alignment with patient and disease features. Impact of the BMETS-DSP on decision outcomes will be further assessed in a randomised, controlled study.

Incidence and Severity of Myelosuppression With Palbociclib After Palliative Bone Radiation in Advanced Breast Cancer: A Single Center Experience and Review of Literature

BACKGROUND

Palbociclib is a cyclin-dependent kinase (CDK) 4/6 inhibitor with a primary toxicity of myelosuppression, especially neutropenia, due to cytostatic CDK6 inhibition on bone marrow. Preclinical studies suggest palbociclib may enhance radiation toxicity, but this was only evaluated in limited case series of palliative radiotherapy and not specific to radiation targeting bony metastases.

PATIENTS AND METHODS

This was a single institution retrospective cohort study. We included female patients who initiated palbociclib for advanced breast cancer between 2015 and 2019. The primary exposure was receipt of palliative radiation to bony metastases within 1 year prior to starting palbociclib. The primary outcome was the incidence and severity of myelosuppression during cycle one. Secondary outcomes include treatment interruptions and cycle 2 dose reductions, with subgroup analysis of radiation timing, type, dose, and location.

RESULTS

Of the 247 patients, 47 received radiation to bone metastases. Only absolute lymphocyte count (ALC) after cycle one of palbociclib was significantly lower in the group receiving radiation (median ALC 0.84 vs. 1.10 K/mm³, P < .001), with similar rates of neutropenia, anemia, and thrombocytopenia. Patients who received ≥10 fractions radiation were more likely to have cycle one interrupted than those receiving shorter radiation courses (42.9% vs. 11.1%, P = .03). No radiation characteristics were associated with other hematologic toxicities or dose reduction.

CONCLUSION

Palliative bone radiation within 1 year prior to palbociclib initiation was associated with greater lymphopenia during the first cycle than patients unexposed to radiation, but not neutropenia, anemia, or thrombocytopenia that would modify treatment.

Treatment of Radiation-Associated Fractures: A Critical Analysis Review

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Fractures that result from radiation-induced bone damage are a recognized adverse effect of radiation therapy (RT).

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The mechanisms of damage from RT are thought to be related to impaired vascularity, aberrations in osteoclast and osteoblast-mediated bone turnover, and compromise of cortical and trabecular microarchitecture.

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Treatment of radiation-associated fractures is challenging, with rates of delayed union and nonunion of >50%.

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Fracture management strategies, each with its own profile of risks and benefits, include prophylactic intramedullary nailing of long bones, open reduction and internal fixation with adjunctive iliac crest or vascularized fibular grafting, and endoprosthetic reconstruction.

External Validation of the Bone Metastases Ensemble Trees for Survival (BMETS) Machine Learning Model to Predict Survival in Patients With Symptomatic Bone Metastases

PURPOSE

The Bone Metastases Ensemble Trees for Survival (BMETS) model uses a machine learning algorithm to estimate survival time following consultation for palliative radiation therapy for symptomatic bone metastases (SBM). BMETS was developed at a tertiary-care, academic medical center, but its validity and stability when applied to external data sets are unknown.

PATIENTS AND METHODS

Patients treated with palliative radiation therapy for SBM from May 2013 to May 2016 at two hospital-based community radiation oncology clinics were included, and medical records were retrospectively reviewed to collect model covariates and survival time. The Kaplan-Meier method was used to estimate overall survival from consultation to death or last follow-up. Model discrimination was estimated using time-dependent area under the curve (tAUC), which was calculated using survival predictions from BMETS based on the initial training data set.

RESULTS

A total of 216 sites of SBM were treated in 182 patients. Most common histologies were breast (27%), lung (23%), and prostate (23%). Compared with the BMETS training set, the external validation population was older (mean age, 67 v 62 years; P < .001), had more primary breast (27% v 19%; P = .03) and prostate cancer (20% v 12%; P = .01), and survived longer (median, 10.7 v 6.4 months). When the BMETS model was applied to the external data set, tAUC values at 3, 6, and 12 months were 0.82, 0.77, and 0.77, respectively. When refit with data from the combined training and external validation sets, tAUC remained > 0.79.

CONCLUSION

BMETS maintained high discriminative ability when applied to an external validation set and when refit with new data, supporting its generalizability, stability, and the feasibility of dynamic modeling.

Low-Dose Image-Guided Pediatric CNS Radiation Therapy: Final Analysis From a Prospective Low-Dose Cone-Beam CT Protocol From a Multinational Pediatrics Consortium

Background:

Lower-dose cone-beam computed tomography protocols for image-guided radiotherapy may permit target localization while minimizing radiation exposure. We prospectively evaluated a lower-dose cone-beam protocol for central nervous system image-guided radiotherapy across a multinational pediatrics consortium.

Methods:

Seven institutions prospectively employed a lower-dose cone-beam computed tomography central nervous system protocol (weighted average dose 0.7 mGy) for patients ≤21 years. Treatment table shifts between setup with surface lasers versus cone-beam computed tomography were used to approximate setup accuracy, and vector magnitudes for these shifts were calculated. Setup group mean, interpatient, interinstitution, and random error were estimated, and clinical factors were compared by mixed linear modeling.

Results:

Among 96 patients, with 2179 pretreatment cone-beam computed tomography acquisitions, median age was 9 years (1-20). Setup parameters were 3.13, 3.02, 1.64, and 1.48 mm for vector magnitude group mean, interpatient, interinstitution, and random error, respectively. On multivariable analysis, there were no significant differences in mean vector magnitude by age, gender, performance status, target location, extent of resection, chemotherapy, or steroid or anesthesia use. Providers rated >99% of images as adequate or better for target localization.

Conclusions:

A lower-dose cone-beam computed tomography protocol demonstrated table shift vector magnitude that approximate clinical target volume/planning target volume expansions used in central nervous system radiotherapy. There were no significant clinical predictors of setup accuracy identified, supporting use of this lower-dose cone-beam computed tomography protocol across a diverse pediatric population with brain tumors.

A multi-institutional phase 2 trial of stereotactic body radiotherapy in the treatment of bone metastases in pediatric and young adult patients with sarcoma

BACKGROUND

Metastasectomy is standard of care for pediatric patients with metastatic sarcoma with limited disease. For patients with unresectable disease, stereotactic body radiotherapy (SBRT) may serve as an alternative. Herein, the authors report the results of a prospective, multi-institutional phase 2 trial of SBRT in children and young adults with metastatic sarcoma.

METHODS

Patients aged >3 years and ≤40 years with unresected, osseous metastatic nonrhabdomyosarcoma sarcomas of soft tissue and bone were eligible. Patients received SBRT to a dose of 40 Gray (Gy) in 5 fractions. Local control (LC), progression-free survival (PFS), and overall survival (OS) were calculated using the Kaplan-Meier method.

RESULTS

Fourteen patients with a median age of 17 years (range, 4-25 years) were treated to 37 distinct metastatic lesions. With a median follow-up of 6.8 months (30.5 months in surviving patients), the Kaplan-Meier patient-specific and lesion-specific LC rates at 6 months were 89% and 95%, respectively. The median PFS was 6 months and the median OS was 24 months. In a post hoc analysis, PFS (median, 9.3 months vs 3.7 months; log-rank P = .03) and OS (median not reached vs 12.7 months; log-rank P = .02) were improved when all known sites of metastatic disease were consolidated with SBRT compared with partial consolidation. SBRT was well tolerated, with 2 patients experiencing grade 3 toxicities.

CONCLUSIONS

SBRT achieved high rates of LC in pediatric patients with inoperable metastatic nonrhabdomyosarcoma sarcomas of soft tissue and bone. These results suggest that the ability to achieve total consolidation of metastatic disease with SBRT is associated with improved PFS and OS.

Physician Practice Variability in the Use of Extended-Fraction Radiation Therapy for Bone Metastases: Are We Choosing Wisely?

PURPOSE:

Routine use of extended-fraction (> 10 fractions) radiation therapy (RT) for palliation of bone metastases is recognized as a low-value intervention by the American Society for Radiation Oncology. We examined contemporary practice patterns of, and physician characteristics associated with extended-fraction RT use.

MATERIALS AND METHODS:

We conducted a retrospective cohort study using Medicare fee-for-service data. We included patients who underwent 2- or 3-dimensional external-beam RT for bone metastases between January 1, 2016, and December 31, 2018. Physicians treating > 10 patients over the study period were analyzed for their individual practice. Hierarchic logistic regression modeling was used to identify patient- and physician-level factors associated with extended-fraction RT use.

RESULTS:

A total of 12,221 patients (median age, 75.6 years; 40.9% women, 87.6% white) were included. The rate of extended-fraction RT was 23.4%. A total of 1,432 physicians treated any patient. Among the 382 physicians treating > 10 patients, 127 (33.2%) used extended-fraction RT > 30% (consensus threshold). Physician factors associated with decreased odds of extended-fraction RT were years since medical school graduation (≤ 10 years and 11-20 years v ≥ 31 years: adjusted odds ratio [aOR], 0.32 [95% CI, 0.20 to 0.51] and 0.64 [95% CI, 0.44 to 0.93]) and practicing in the Northeast or Midwest versus the South (aOR, 0.36 [95% CI, 0.22 to 0.58] and 0.48 [95% CI, 0.31 to 0.74]). Physicians treating > 20 patients ( v 11-14 patients) over the study period had increased odds of delivering extended-fraction RT (aOR, 1.53 [95% CI, 1.10 to 2.12]).

CONCLUSION:

In this study, almost one fourth of patients received extended-fraction RT, and one third of physicians had an extended-fraction RT use rate of > 30%. Personalized feedback of performance data, clinical pathways and peer review, and updated reimbursement models are potential mechanisms to address this low-value care.

Developing an Improved Statistical Approach for Survival Estimation in Bone Metastases Management: The Bone Metastases Ensemble Trees for Survival (BMETS) Model

PURPOSE

To determine whether a machine learning approach optimizes survival estimation for patients with symptomatic bone metastases (SBM), we developed the Bone Metastases Ensemble Trees for Survival (BMETS) to predict survival using 27 prognostic covariates. To establish its relative clinical utility, we compared BMETS with 2 simpler Cox regression models used in this setting.

METHODS AND MATERIALS

For 492 bone sites in 397 patients evaluated for palliative radiation therapy (RT) for SBM from January 2007 to January 2013, data for 27 clinical variables were collected. These covariates and the primary outcome of time from consultation to death were used to build BMETS using random survival forests. We then performed Cox regressions as per 2 validated models: Chow's 3-item (C-3) and Westhoff's 2-item (W-2) tools. Model performance was assessed using cross-validation procedures and measured by time-dependent area under the curve (tAUC) for all 3 models. For temporal validation, a separate data set comprised of 104 bone sites treated in 85 patients in 2018 was used to estimate tAUC from BMETS.

RESULTS

Median survival was 6.4 months. Variable importance was greatest for performance status, blood cell counts, recent systemic therapy type, and receipt of concurrent nonbone palliative RT. tAUC at 3, 6, and 12 months was 0.83, 0.81, and 0.81, respectively, suggesting excellent discrimination of BMETS across postconsultation time points. BMETS outperformed simpler models at each time, with respective tAUC at each time of 0.78, 0.76, and 0.74 for the C-3 model and 0.80, 0.78, and 0.77 for the W-2 model. For the temporal validation set, respective tAUC was similarly high at 0.86, 0.82, and 0.78.

CONCLUSIONS

For patients with SBM, BMETS improved survival predictions versus simpler traditional models. Model performance was maintained when applied to a temporal validation set. To facilitate clinical use, we developed a web platform for data entry and display of BMETS-predicted survival probabilities.

Acute toxicity outcomes and dosimetric implications from incidental irradiation of adjacent tissues in tangent field hypofractionated breast radiotherapy

PURPOSE

Adjacent tissues-in-beam (TIB) may receive substantial incidental doses within standard tangent fields during hypofractioned whole breast irradiation (HF-WBI). To characterize the impact of dose to TIB, we analyzed dosimetric parameters of TIB and associated acute toxicity.

MATERIALS AND METHODS

Plans prescribed to 40.5 Gy/15 fractions from 4/2016-1/2018 were evaluated. Structures of interest were contoured: (1) TIB: all tissues encompassed by plan 30% isodose lines, (2) breast, (3) non-breast TIB (nTIB): TIB minus contoured breast. Volumes of TIB, breast, and nTIB receiving 100%-107% of prescription dose (V100-V107) were calculated. Twelve patient- and physician-reported acute toxicities were prospectively collected weekly. Correlations between volumetric and dosimetric parameters were assessed. Uni- and multivariable logistic regressions evaluated toxicity grade changes as a function of TIB, breast, and nTIB V100-V107 (in cm3).

RESULTS

We evaluated 137 plans. Breast volume was positively correlated with nTIB and nTIB V100 (rho = 0.52, rho = 0.30, respectively, both p < 0.001). V107 > 2 cm3 were noted in 14% of breast and 21% of nTIB volumes. On multivariable analyses, increasing breast and nTIB V100 significantly raised odds of grade 2+ dermatitis and burning/twinging pain, respectively; increasing nTIB V105 elevated odds of hyperpigmentation and burning pain; and increasing nTIB V107 raised odds of burning pain. Threshold volumes for >6-fold odds of developing burning pain were TIB V105 > 100 cm3 and V107 > 5 cm3.

CONCLUSIONS

For HF-WBI, doses to nTIB over the prescription predicted acute toxicities independent of breast doses. These data support inclusion of TIB as a region of interest in treatment planning and protocol design.

Frequency of Complicated Symptomatic Bone Metastasis Over a Breadth of Operational Definitions

PURPOSE

Numerous randomized trials have demonstrated noninferiority of single- versus multiple-fraction palliative radiation therapy (RT) in the management of uncomplicated bone metastases; yet there is neither a clear definition of what constitutes a complicated lesion, nor substantial data regarding the prevalence of such complicating features in clinical practice. Thus, we identify a range of evidence-based operational definitions of complicated symptomatic bone metastases and characterize the frequency of such complicating features at a high-volume, tertiary care center.

METHODS AND MATERIALS

A retrospective review of patients seen in consultation for symptomatic bone metastases between March 1, 2007, and July 31, 2013, at Johns Hopkins Hospital identified patient and disease characteristics. Descriptive statistics characterized the frequency of the following complicating features: prior RT, prior surgery, neuraxis compromise, pathologic fracture, and soft tissue component at the symptomatic site. A range of definitions for complicated bone metastases was evaluated based on combinations of these features. Uni- and multivariable logistic regressions evaluated the odds of complicated bone metastases as a function of site of primary cancer and of the symptomatic target lesion.

RESULTS

A total of 686 symptomatic bone metastases in 401 patients were evaluated. Percent of target sites complicated by prior RT was 4.4%, prior surgery was 8.9%, pathologic fracture was 20.6%, neuraxis compromise was 52.0% among spine and medial pelvis sites, and soft tissue component was 38.6%. More than 96 possible definitions of complicated bone metastases were identified. The presence of such complicated lesions ranged from 2.3% to 67.3%, depending on the operational definition used. Odds of a complicated lesion were significantly higher for spine sites and select nonbreast histologies.

CONCLUSIONS

In this retrospective study, we found complicated symptomatic bone metastases may be present in up to two-thirds of patients. Literature review also demonstrates no clear standard definition of complicated bone metastases, potentially explaining underutilization of single-fraction palliative RT in this setting.

Clinical practice and outcomes of palliative radiation therapy in pediatric oncology patients: An international comparison of experiences from two distinct countries and health care systems

BACKGROUND AND PURPOSE

This study describes clinical outcomes of palliative radiation therapy (RT) for children treated in distinct health-care environments-the US where there is advanced integration of palliative resources and Brazil, a country in the process of developing provisions for pediatric palliative care.

METHODS AND MATERIALS

Palliative RT cases of pediatric oncology patients aged ≤21-years from 2010 to 2016 in two Brazil-based and one US-based (Johns Hopkins Hospital, JHH) academic centers were reviewed in this study.

RESULTS

Eighty-eight pediatric patients were treated to 131 lesions with palliative RT. Forty-nine patients from the JHH cohort comprised 84 cases and 39 patients from the Brazil cohort comprised 46 cases. The most common indication for palliative RT was pain (55% overall, 39% Brazil, 63% JHH). Sixty-seven percent of patients experienced a complete (CR) or partial response (PR) to palliative RT, 12% reported stable symptoms (SS), and 22% reported progressive symptoms (PS). The median survival from the end of palliative RT was 3.6 months (95% confidence interval (CI), 2.3-4.8 months). When treated with palliative RT for pain, 83% of patients experience CR/PR, facilitating reduction or discontinuation of opiates in 46% of these patients.

CONCLUSION

Despite different practices, the clinical results using palliative RT for pediatric patients treated in two unique healthcare environments demonstrated it is an effective tool for pediatric oncology patients across systems.

Association of a Simulated Institutional Gender Equity Initiative With Gender-Based Disparities in Medical School Faculty Salaries and Promotions

IMPORTANCE

Despite progress in narrowing gender-based salary gaps, notable disparities persist in the scientific community. The significance of pay difference may be underestimated, with little data evaluating its effect on lifetime wealth after accounting for factors like time to promotion and savings.

OBJECTIVES

To characterize gender disparities in salary and assess the outcomes associated with a gender equity initiative (GEI).

DESIGN, SETTING, AND PARTICIPANTS

Quality improvement study with simulations of salary and additional accumulated wealth (AAW) using retrospectively reviewed Johns Hopkins University School of Medicine annual salary and promotion data. All academic faculty were included in the faculty salary analysis from 2005 (n = 1481) and 2016 (n = 1885).

MAIN OUTCOMES AND MEASURES

Salary and longitudinal promotion data from 2005 to 2016 were used to estimate gender-based differences in salary and time to promotion. The effect of these differences on total salary and AAW, including retirement and salary-based investments, was simulated for a representative male and female faculty member over a 30-year career in 3 scenarios: (1) pre-GEI, (2) post-GEI, and (3) in real time for GEI, beginning with and progressing through these initiatives.

RESULTS

Analyses of salaries of 1481 faculty (432 women) in 2005 and 1885 faculty (742 women) in 2016 revealed that a decade after GEI implementation, the overall mean (SE) salary gap by gender decreased from -2.6% (1.2%) (95% CI, -5.6% to -0.3%) to -1.9% (1.1%) (95% CI, -4.1% to 0.3%). Simulation of pre-GEI disparities correlated with male faculty collecting an average lifetime AAW of $501 416 more than the equivalent woman, with disparities persisting past retirement. The AAW gap decreased to $210 829 in the real-time GEI simulation and to $66 104 using post-GEI conditions, reflecting success of GEI efforts.

CONCLUSIONS AND RELEVANCE

Even small gender-based salary gaps are associated with substantial differences in lifetime wealth, but an institutional commitment to achieving equitable promotion and compensation for women can appreciably reduce these disparities. The findings of this study support broad implementation of similar initiatives without delay, as results may take more than a decade to emerge. A modifiable version of the simulation is provided so that external users may assess the potential disparities present within their own institutions.

Practice patterns of palliative radiation therapy in pediatric oncology patients in an international pediatric research consortium

BACKGROUND/OBJECTIVES

The practice of palliative radiation therapy (RT) is based on extrapolation from adult literature. We evaluated patterns of pediatric palliative RT to describe regimens used to identify opportunity for future pediatric-specific clinical trials.

DESIGN/METHODS

Six international institutions with pediatric expertise completed a 122-item survey evaluating patterns of palliative RT for patients ≤21 years old from 2010 to 2015. Two institutions use proton RT. Palliative RT was defined as treatment with the goal of symptom control or prevention of immediate life-threatening progression.

RESULTS

Of 3,225 pediatric patients, 365 (11%) were treated with palliative intent to a total of 427 disease sites. Anesthesia was required in 10% of patients. Treatment was delivered to metastatic disease in 54% of patients. Histologies included neuroblastoma (30%), osteosarcoma (18%), leukemia/lymphoma (12%), rhabdomyosarcoma (12%), medulloblastoma/ependymoma (12%), Ewing sarcoma (8%), and other (8%). Indications included pain (43%), intracranial symptoms (23%), respiratory compromise (14%), cord compression (8%), and abdominal distention (6%). Sites included nonspine bone (35%), brain (16% primary tumors, 6% metastases), abdomen/pelvis (15%), spine (12%), head/neck (9%), and lung/mediastinum (5%). Re-irradiation comprised 16% of cases. Techniques employed three-dimensional conformal RT (41%), intensity-modulated RT (23%), conventional RT (26%), stereotactic body RT (6%), protons (1%), electrons (1%), and other (2%). The most common physician-reported barrier to consideration of palliative RT was the concern about treatment toxicity (83%).

CONCLUSION

There is significant diversity of practice in pediatric palliative RT. Combined with ongoing research characterizing treatment response and toxicity, these data will inform the design of forthcoming clinical trials to establish effective regimens and minimize treatment toxicity for this patient population.

Practice patterns of photon and proton pediatric image guided radiation treatment: results from an International Pediatric Research consortium

PURPOSE

Image guided radiation therapy (IGRT) has become common practice for both photon and proton radiation therapy, but there is little consensus regarding its application in the pediatric population. We evaluated clinical patterns of pediatric IGRT practice through an international pediatrics consortium comprised of institutions using either photon or proton radiation therapy.

METHODS AND MATERIALS

Seven international institutions with dedicated pediatric expertise completed a 53-item survey evaluating patterns of IGRT use in definitive radiation therapy for patients ≤21 years old. Two institutions use proton therapy for children and all others use IG photon therapy. Descriptive statistics including frequencies of IGRT use and means and standard deviations for planning target volume (PTV) margins by institution and treatment site were calculated.

RESULTS

Approximately 750 pediatric patients were treated annually across the 7 institutions. IGRT was used in tumors of the central nervous system (98%), abdomen or pelvis (73%), head and neck (100%), lung (83%), and liver (69%). Photon institutions used kV cone beam computed tomography and kV- and MV-based planar imaging for IGRT, and all proton institutions used kV-based planar imaging; 57% of photon institutions used a specialized pediatric protocol for IGRT that delivers lower dose than standard adult protocols. Immobilization techniques varied by treatment site and institution. IGRT was utilized daily in 45% and weekly in 35% of cases. The PTV margin with use of IGRT ranged from 2 cm to 1 cm across treatment sites and institution.

CONCLUSIONS

Use of IGRT in children was prevalent at all consortium institutions. There was treatment site-specific variability in IGRT use and technique across institutions, although practices varied less at proton facilities. Despite use of IGRT, there was no consensus of optimum PTV margin by treatment site. Given the desire to restrict any additional radiation exposure in children to instances where the exposure is associated with measureable benefit, prospective studies are warranted to optimize IGRT protocols by modality and treatment site.

Patterns of palliative radiation near the end of life: A single-institution retrospective analysis

9636

Background: The care of patients who receive radiation therapy (RT) at the end of life (EOL) is under scrutiny to ensure effectiveness and value, with many patients not completing RT (Gripp, 2010; Toole, 2012). This retrospective analysis seeks to describe patterns of utilization of palliative RT, including rates of completion of RT offered at the EOL and the use of single fraction RT for bone metastases. Methods: Electronic medical records were used to create a database of 3,383 RT plans for brain, bone, lung, and other metastatic sites in patients treated at Johns Hopkins Hospital from 9/1/2007-7/15/2012. RT plans without palliative intent were excluded. T-tests and logistic regression compared patient and treatment characteristics between patients who died > 1 month versus ≤ 1 month after their last RT fraction. Results: A total of 983 patients were treated to 1,524 sites, with an average of 1.7 RT sites (SD 1.3) per patient. Of these, 872 (89%) patients had complete records and were included in analysis. At the time of analysis, 85% had died. The mean age of 62.1 years (SD 3.4) did not differ statistically based on time from RT to death. Death ≤ 1 month after RT was documented in 215 (24.7%) patients. Compared to patients living > 1 month after RT, patients receiving RT within the last month of life were more likely to be lung (17% versus 9%), less likely to be brain (34% versus 44%), and equally likely to be bone (45% versus 43%) sites. Patients who died ≤ 1 month after completing RT spent on average 5 days (16.6%) of the last month of life receiving RT, with no significant difference by disease site. Conclusions: Most patients receiving palliative RT finish therapy, with 25% dying ≤ 1 month after RT. Single fraction bone RT was relatively uncommon, with no significant difference in the rates of single fraction RT based on time from RT to death. These data provide a framework to match treatment patterns with national guidelines. Additionally, they provide context to model risk of death shortly after RT, which can aid in clinical decision-making. [Table: see text]

"If God wanted me yesterday, I wouldn't be here today": religious and spiritual themes in patients' experiences of advanced cancer

BACKGROUND

This study sought to inductively derive core themes of religion and/or spirituality (R/S) active in patients' experiences of advanced cancer to inform the development of spiritual care interventions in the terminally ill cancer setting.

METHODS

This is a multisite, cross-sectional, mixed-methods study of randomly-selected patients with advanced cancer (n = 68). Scripted interviews assessed the role of R/S and R/S concerns encountered in the advanced cancer experience. Qualitative and quantitative data were analyzed. Theme extraction was performed with interdisciplinary input (sociology of religion, medicine, theology), utilizing grounded theory. Spearman correlations determined the degree of association between R/S themes. Predictors of R/S concerns were assessed using linear regression and analysis of variance.

RESULTS

Most participants (n = 53, 78%) stated that R/S had been important to the cancer experience. In descriptions of how R/S was related to the cancer experience, five primary R/S themes emerged: coping, practices, beliefs, transformation, and community. Most interviews (75%) contained two or more R/S themes, with 45% mentioning three or more R/S themes. Multiple significant subtheme interrelationships were noted between the primary R/S themes. Most participants (85%) identified 1 or more R/S concerns, with types of R/S concerns spanning the five R/S themes. Younger, more religious, and more spiritual patients identified R/S concerns more frequently (beta = -0.11, p < 0.001; beta = 0.83, p = 0.03; and beta = 0.89, p = 0.04, respectively).

CONCLUSIONS

R/S plays a variety of important and inter-related roles for most advanced cancer patients. Future research is needed to determine how spiritual care can incorporate these five themes and address R/S concerns.