Hypofractionated radiotherapy for glioblastoma: A large institutional retrospective assessment of 2 approaches

Background

Glioblastoma (GBM) poses therapeutic challenges due to its aggressive nature, particularly for patients with poor functional status and/or advanced disease. Hypofractionated radiotherapy (RT) regimens have demonstrated comparable disease outcomes for this population while allowing treatment to be completed more quickly. Here, we report our institutional outcomes of patients treated with 2 hypofractionated RT regimens: 40 Gy/15fx (3w-RT) and 50 Gy/20fx (4w-RT).

Methods

A single-institution retrospective analysis was conducted of 127 GBM patients who underwent 3w-RT or 4w-RT. Patient characteristics, treatment regimens, and outcomes were analyzed. Univariate and multivariable Cox regression models were used to estimate progression-free survival (PFS) and overall survival (OS). The impact of chemotherapy and RT schedule was explored through subgroup analyses.

Results

Median OS for the entire cohort was 7.7 months. There were no significant differences in PFS or OS between 3w-RT and 4w-RT groups overall. Receipt and timing of temozolomide (TMZ) emerged as the variable most strongly associated with survival, with patients receiving adjuvant-only or concurrent and adjuvant TMZ having significantly improved PFS and OS (P < .001). In a subgroup analysis of patients that did not receive TMZ, patients in the 4w-RT group demonstrated a trend toward improved OS as compared to the 3w-RT group (P = .12).

Conclusions

This study demonstrates comparable survival outcomes between 3w-RT and 4w-RT regimens in GBM patients. Receipt and timing of TMZ were strongly associated with survival outcomes. The potential benefit of dose-escalated hypofractionation for patients not receiving chemotherapy warrants further investigation and emphasizes the importance of personalized treatment approaches.

Travel-Time Disparities in Access to Proton Beam Therapy for Cancer Treatment

Importance

Proton beam therapy is an emerging radiotherapy treatment for patients with cancer that may produce similar outcomes as traditional photon-based therapy for many cancers while delivering lower amounts of toxic radiation to surrounding tissue. Geographic proximity to a proton facility is a critical component of ensuring equitable access both for indicated diagnoses and ongoing clinical trials.

Objective

To characterize the distribution of proton facilities in the US, quantify drive-time access for the population, and investigate the likelihood of long commutes for certain population subgroups.

Design, Setting, and Participants

This population-based cross-sectional study analyzed travel times to proton facilities in the US. Census tract variables in the contiguous US were measured between January 1, 2017, and December 31, 2021. Statistical analysis was performed from September to November 2023.

Exposures

Drive time in minutes to nearest proton facility. Population totals and prevalence of specific factors measured from the American Community Survey: age; race and ethnicity; insurance, disability, and income status; vehicle availability; broadband access; and urbanicity.

Main Outcomes and Measures

Poor access to proton facilities was defined as having a drive-time commute of at least 4 hours to the nearest location. Median drive time and percentage of population with poor access were calculated for the entire population and by population subgroups. Univariable and multivariable odds of poor access were also calculated for certain population subgroups.

Results

Geographic access was considered for 327 536 032 residents of the contiguous US (60 594 624 [18.5%] Hispanic, 17 974 186 [5.5%] non-Hispanic Asian, 40 146 994 [12.3%] non-Hispanic Black, and 195 265 639 [59.6%] non-Hispanic White; 282 031 819 [86.1%] resided in urban counties). The median (IQR) drive time to the nearest proton facility was 96.1 (39.6-195.3) minutes; 119.8 million US residents (36.6%) lived within a 1-hour drive of the nearest proton facility, and 53.6 million (16.4%) required a commute of at least 4 hours. Persons identifying as non-Hispanic White had the longest median (IQR) commute time at 109.8 (48.0-197.6) minutes. Multivariable analysis identified rurality (odds ratio [OR], 2.45 [95% CI, 2.27-2.64]), age 65 years or older (OR, 1.09 [95% CI, 1.06-1.11]), and living below the federal poverty line (OR, 1.22 [1.20-1.25]) as factors associated with commute times of at least 4 hours.

Conclusions and Relevance

This cross-sectional study of drive-time access to proton beam therapy found that disparities in access existed among certain populations in the US. These results suggest that such disparities present a barrier to an emerging technology in cancer treatment and inhibit equitable access to ongoing clinical trials.

Patient Education Practices and Preferences of Radiation Oncologists and Interprofessional Radiation Therapy Care Teams: A Mixed-Methods Study Exploring Strategies for Effective Patient Education Delivery

PURPOSE

Patients' understanding of radiation therapy (RT) and data regarding optimal approaches to patient education (PE) within radiation oncology (RO) are limited. We aimed to evaluate PE practices of radiation oncologists and interprofessional RT care team members to inform recommendations for delivering inclusive and accessible PE.

METHODS AND MATERIALS

An anonymous survey was administered to all Radiation Oncology Education Collaborative Study Group members (10/5/22-11/23/22). Respondent demographics, individual practices/preferences, and institutional practices were collected. Qualitative items explored strategies, challenges, and desired resources for PE. Descriptive statistics summarized survey responses. The Fisher exact test compared PE practices by respondent role and PE timing. Thematic analysis was used for qualitative responses.

RESULTS

One hundred thirteen Radiation Oncology Education Collaborative Study Group members completed the survey (28.2% response rate); RO attendings comprised 68.1% of respondents. Most practiced in an academic setting (85.8%) in North America (80.5%). Institution-specific materials were the most common PE resource used by radiation oncologists (67.6%). Almost half (40.2%) reported that their PE practices differed based on clinical encounter type, with paper handouts commonly used for in-person and multimedia for telehealth visits. Only 57.7% reported access to non-English PE materials. PE practices among radiation oncologists differed according to RT clinical workflow timing (consultation versus simulation versus first RT, respectively): one-on-one teaching: 88.5% versus 49.4% versus 56.3%, P < .01, and paper handouts: 69.0% versus 28.7% versus 16.1%, P < .01. Identified challenges for PE delivery included limited time, administrative barriers to the development or implementation of new materials or practices, and a lack of customized resources for tailored PE. Effective strategies for PE included utilization of visual diagrams, multimedia, and innovative education techniques to personalize PE delivery/resources for a diverse patient population, as well as fostering interprofessional collaboration to reinforce educational content.

CONCLUSIONS

Radiation oncologists and interprofessional RO team members engage in PE, with most using institution-specific materials often available only in English. PE practices differ according to clinical encounter type and RT workflow timing. Increased adoption of multimedia materials and partnerships with patients to tailor PE resources are needed to foster high-quality, patient-centered PE delivery.

Daily Vaginal Dilator Use During Radiation for Women With Squamous Cell Carcinoma of the Anus: Vaginal Wall Dosimetry and Patient-Reported Sexual Function

PURPOSE

At our institution, we treat patients with a daily vaginal dilator (VD) during chemoradiation (CRT) for squamous cell carcinoma of the anus (SCCA). We evaluated compliance with daily VD use, radiation dose to the vaginal wall (VW), and anterior vaginal wall (AVW), and patient-reported long-term sexual function.

METHODS AND MATERIALS

We included women with SCCA who received definitive, intensity-modulated radiation therapy-based CRT. Women who were alive without evidence of disease received a patient-reported outcome survey, which included the Female Sexual Function Index (FSFI). We identified factors associated with FSFI, such as radiation dose to the VW and AVW using linear regression models and used Youden index analysis to estimate a dose cutoff to predict sexual dysfunction.

RESULTS

Three hundred thirty-nine consecutively treated women were included in the analysis; 285 (84.1%) were treated with a daily VD. Of 184 women alive without disease, 90 patients (49%) completed the FSFI, and 51 (56.7%) were sexually active with valid FSFI scores. All received therapy with a daily VD. Forty-one women (80%) had sexual dysfunction. Univariate analysis showed higher dose to 50% (D50%) of the AVW correlated with worse FSFI (β -.262; P = .043), worse desire FSFI subscore (β -.056; P = .003), and worse pain FSFI subscore (β -.084; P = .009). Younger age correlated with worse pain FSFI subscale (β .067; P = .026). Age (β .070; P = .013) and AVW D50% (β -.087; P = .009) were significant on multivariable analysis. AVW D50% >48 Gy predicted increased risk of sexual dysfunction.

CONCLUSIONS

Daily VD use is safe and well tolerated during CRT for SCCA. Using a VD during treatment to displace the AVW may reduce the risk for sexual dysfunction. Limiting the AVW D50% <48 Gy may further reduce the risk but additional data are needed to validate this constraint.

Salvage Treatment of Recurrent or Persistent Anal Squamous Cell Carcinoma: The Role of Multi-modality Therapy

BACKGROUND

The standard treatment for recurrent or persistent anal squamous cell carcinoma is surgical salvage, but disease control and survival are suboptimal.

PATIENTS/METHODS

Patients treated for recurrent or persistent anal squamous cell carcinoma at our institution from 2002 to 2022 were included. Patients were classified by type of salvage treatment received: surgery alone vs. reirradiation followed by surgery and by whether they received intraoperative radiation at the time of surgery. Clinical and pathologic variables were collected and assessed for association with risk of second local recurrence and death from any cause.

RESULTS

Sixty four patients were included; 55(85.9%) were treated with surgery alone and 9 (14.1%) were treated with reirradiation followed by surgery. Median (IQR) follow up from the time of salvage treatment was 40.0 (20.3-68.0) months. The 3-year cumulative incidence of second local recurrence (95% CI) after salvage surgery was 36% (24%-48%); 39% (26%-52%) for patients treated with surgery alone and 15% (0.46%-51%) for patients treated with reirradiation followed by surgery. Factors associated with increased second local recurrence after salvage surgery included a locoregional recurrence, lymphovascular space invasion and positive surgical margins. The 3-year overall survival (95% CI) after salvage surgery was 70% (59%-83%); 68% (7%-56%) after surgery alone and 89% (10.5%-70.6%) after reirradiation followed by surgery. Factors associated with worse overall survival included male sex, a larger recurrent tumor and positive surgical margins.

CONCLUSIONS

Approximately 60% of patients achieved pelvic control after salvage therapy for recurrent or persistent anal squamous cell carcinoma. Although receipt of reirradiation and intraoperative radiation were not associated with improved second local recurrence or overall survival in our cohort, patients with positive surgical margins and lymphovascular space invasion on surgical pathology had higher rates of pelvic recurrence after salvage surgery and may benefit from escalated salvage therapy.

Random Forest Modeling of Acute Toxicity in Anal Cancer: Effects of Peritoneal Cavity Contouring Approaches on Model Performance

PURPOSE

Our purpose was to analyze the effect on gastrointestinal (GI) toxicity models when their dose-volume metrics predictors are derived from segmentations of the peritoneal cavity after different contouring approaches.

METHODS AND MATERIALS

A random forest machine learning approach was used to predict acute grade ≥3 GI toxicity from dose-volume metrics and clinicopathologic factors for 246 patients (toxicity incidence = 9.5%) treated with definitive chemoradiation for squamous cell carcinoma of the anus. Three types of random forest models were constructed based on different bowel bag segmentation approaches: (1) physician-delineated after Radiation Therapy Oncology Group (RTOG) guidelines, (2) autosegmented by a deep learning model (nnU-Net) following RTOG guidelines, and (3) autosegmented but spanning the entire bowel space. Each model type was evaluated using repeated cross-validation (100 iterations; 50%/50% training/test split). The performance of the models was assessed using area under the precision-recall curve (AUPRC) and the receiver operating characteristic curve (AUROCC), as well as optimal F1 score.

RESULTS

When following RTOG guidelines, the models based on the nnU-Net auto segmentations (mean values: AUROCC, 0.71 ± 0.07; AUPRC, 0.42 ± 0.09; F1 score, 0.46 ± 0.08) significantly outperformed (P < .001) those based on the physician-delineated contours (mean values: AUROCC, 0.67 ± 0.07; AUPRC, 0.34 ± 0.08; F1 score, 0.36 ± 0.07). When spanning the entire bowel space, the performance of the autosegmentation models improved considerably (mean values: AUROCC, 0.87 ± 0.05; AUPRC, 0.70 ± 0.09; F1 score, 0.68 ± 0.09).

CONCLUSIONS

Random forest models were superior at predicting acute grade ≥3 GI toxicity when based on RTOG-defined bowel bag autosegmentations rather than physician-delineated contours. Models based on autosegmentations spanning the entire bowel space show further considerable improvement in model performance. The results of this study should be further validated using an external data set.

Patient-Reported Sexual Function, Bladder Function and Quality of Life for Patients with Low Rectal Cancers with or without a Permanent Ostomy

BACKGROUND

Despite the increasing utilization of sphincter and/or organ-preservation treatment strategies, many patients with low-lying rectal cancers require abdominoperineal resection (APR), leading to permanent ostomy. Here, we aimed to characterize overall, sexual-, and bladder-related patient-reported quality of life (QOL) for individuals with low rectal cancers. We additionally aimed to explore potential differences in patient-reported outcomes between patients with and without a permanent ostomy.

METHODS

We distributed a comprehensive survey consisting of various patient-reported outcome measures, including the FACT-G7 survey, ICIQ MLUTS/FLUTS, IIEF-5/FSFI, and a specific questionnaire for ostomy patients. Descriptive statistics and univariate comparisons were used to compared demographics, treatments, and QOL scores between patients with and without a permanent ostomy.

RESULTS

Of the 204 patients contacted, 124 (60.8%) returned completed surveys; 22 (18%) of these had a permanent ostomy at the time of survey completion. There were 25 patients with low rectal tumors (≤5 cm from the anal verge) who did not have an ostomy at the time of survey completion, of whom 13 (52%) were managed with a non-operative approach. FACTG7 scores were numerically lower (median 20.5 vs. 22, p = 0.12) for individuals with an ostomy. Sexual function measures IIEF and FSFI were also lower (worse) for individuals with ostomies, but the results were not significantly different. MLUTS and FLUTS scores were both higher in individuals with ostomies (median 11 vs. 5, p = 0.06 and median 17 vs. 5.5, p = 0.01, respectively), suggesting worse urinary function. Patient-reported ostomy-specific challenges included gastrointestinal concerns (e.g., gas, odor, diarrhea) that may affect social activities and personal relationships.

CONCLUSIONS

Despite a limited sample size, this study provides patient-centered, patient-derived data regarding long-term QOL in validated measures following treatment of low rectal cancers. Ostomies may have multidimensional negative impacts on QOL, and these findings warrant continued investigation in a prospective setting. These results may be used to inform shared decision making for individuals with low rectal cancers in both the settings of organ preservation and permanent ostomy.

Outcomes with Bridging Radiation Therapy Prior to CAR-T Cell Therapy in Pts with Aggressive B Cell Lymphomas

PURPOSE/OBJECTIVE(S)

Select patient (pts) with relapsed/refractory aggressive B cell lymphoma may benefit from bridging radiation (bRT) prior to anti-CD19-directed chimeric antigen receptor T cell therapy (CART). Here, we examined pt and treatment factors associated with outcome after bRT and CART.

MATERIALS/METHODS

We retrospectively reviewed adults with DLBCL who received bRT prior to axicabtagene ciloleucel 11/2017-12/2022. Clinical/treatment characteristics, response, and toxicity were extracted. Progression free survival (PFS), disease specific survival (DSS) and overall survival (OS) were modeled using Kaplan-Meier for events distributed over time, or binary logistic regression for disease response. Fisher's Exact Test or Mann-Whitney U methods were used.

RESULTS

Among 40 pts, 11 (28%) had limited stage disease at apheresis, and 14 (35%) received bRT in addition to bridging systemic therapy. Thirty-two (80%) pts received bRT post-leukapheresis. bRT was delivered with a median dose of 30 Gy (range: 4-46) in 10 fractions (range: 2-23). Eighteen (45%) pts received <30 Gy. Twenty-two pts (55%) received bRT comprehensively to all sites of disease, including 9 pts who had limited stage. Eleven pts had bulky disease (≥ 10 cm) at the time of bRT. After CART, 4 pts (10%) experienced Grade ≥3 cytokine release syndrome (CRS), 16 (40%) had Grade ≥2 CRS, and 16 (38%) had Grade ≥3 neurotoxicity. Twenty-three pts (57.5%) had CR at 30 days post-CART infusion. Nine had PR (22.5%), of whom 2 pts eventually developed CR at three months and 1 at nine months. Eight pts (20%) had either PD or SD. Of 23 pts who experienced CR, 11 relapsed-6 at three months and 5 at six months. At a median follow up of 9.6 months (95% CI: 6.6-16.2), 22 pts relapsed: 6 (27.3%) in-field, 10 (5.5%) out-of-field, 4 (18.2%) both, and 2 (9.1%) unknown. The median PFS was 8.87 months and median OS was 22 months. PFS at 1 year was 70% (53-82) and at 2 years was 42% (27-57). OS at 1 and 2 years was 72.5% (56-84) and 51% (34-65), respectively. Seventeen pts (42.5%) remain alive at last follow-up, 13 (76.5%) of whom have no evidence of disease (NED). On univariate analysis, OS and PFS at 1 year were 67% (43-83) and 49% (27-68) for those who received RT comprehensively (n = 22), and 41.9% (19-64) and 33.3% (14-54) for those who did not (n = 18; both p≤0.03). Disease bulk (≥10 cm) was associated with significant decrement in DSS (p = 0.03), but not PFS (p = 0.16) or OS (p = 0.24). Among pts treated comprehensively with bRT (n = 22), there was no association of tumor bulk with OS, PFS, or DSS (p>0.2). IPI ≥3 was associated with worse DSS (p = 0.045) and trended towards worse PFS (p = 0.054), but not OS (p = 0.23). There was no difference in PFS, OS, or DSS between pts who received bRT or chemoRT (p>0.3).

CONCLUSION

bRT and CART is a good treatment strategy for select pts with aggressive B cell lymphoma. When feasible, and with a caveat that other variables influence patient disposition, bRT for CART is associated with improved outcomes after comprehensive RT to all sites of disease.

Predictors of Low Anterior Resection Syndrome after Long-Course Chemoradiation for Locally Advanced Rectal Cancer

PURPOSE/OBJECTIVE(S)

Low anterior resection syndrome (LARS) describes disordered bowel function including tenesmus, frequent, clustered, incomplete, urgent or incontinent bowel movements. The impact of clinical and radiation dosimetric factors on LARS score is unknown. We aimed to evaluate the radiation plans for patients who received long course chemoradiation (LC-CRT) to identify potential dosimetric predictors of LARS.

MATERIALS/METHODS

We identified patients with rectal cancer treated with LC-CRT (50.4Gy in 28 fractions) at our institution from 2016-2020 who were alive and without disease. As a part of a larger patient-reported outcome survey, we obtained the Low Anterior Resection Syndrome Score (LARS) for patients without an ostomy at the time of the survey. We utilized clinical and dosimetric variables in a multivariate analysis including age at LC-CRT, body mass index, sex, distance of the tumor from the anal verge (AV), threatened mesorectal fascia (MRF) on staging imaging, T-stage, N-stage, receipt of surgery (vs non-operative management (NOM), radiation technique (3DCRT vs VMAT), mean dose and D0.03ccs for the anal canal (defined as 4cm from the anal verge) and D0.03cc, V30Gy and V45Gy for the small bowel loops. We then created a multiple linear regression model to predict LARS using P>.20 on univariate testing.

RESULTS

Of 110 patients treated with preoperative LC-CRT and who did not have an ostomy, 57 responded (51.8%). The median [interquartile range (IQR)] interval from completion of LC-CRT to survey completion was 38.4 months [26.3-48.9]. Thirty-four patients (60%) were men, the median [IQR] BMI was 28 [24-31.9], the median [IQR] distance of the tumor to the anal verge was 7cm [5-10], 40 (70%) had T3 tumors, 7 (12%) had T4 tumors, 45 (79%) were N+. Forty-one patients (72%) had surgery following LC-CRT, and 16 (28%) had non-operative management. 3D conformal technique was used for 47 (82%) and VMAT used for 10 patients (18%). The median [IQR] LARS score was 32 [24-38] with 35 patients (61%) classified as Major LARS (LARS score = 30-42). On multiple linear regression modeling (Table), only receipt of surgery significantly predicted for higher (worse) LARS score.

CONCLUSION

In our cohort, patients who received surgery after LC-CRT had a significantly higher LARS score. Of the dosimetric parameters tested, D0.03ccs was the best predictor and could potentially be significant with a larger number of patients. Further work is needed to improve bowel function and quality of life for patients treated with LC-CRT for rectal adenocarcinoma.

Characterization of Lymphopenia during Bridging Radiation Therapy Prior to CAR-T Cell Therapy in Patients with Aggressive B Cell Lymphomas

PURPOSE/OBJECTIVE(S)

Bridging RT (bRT) may be used as a strategy for disease control in patients with relapsed/refractory aggressive B cell lymphoma treated with anti-CD19-directed chimeric antigen receptor T-cell therapy (CART). The correlation of treatment-related lymphopenia with adverse outcomes in patients has been widely documented in several malignancies. Here, we assessed lymphocyte kinetics during bRT and impact on clinical outcome.

MATERIALS/METHODS

After IRB-approval, records were retrospectively reviewed for adults with DLBCL who received bRT for axicabtagene ciloleucel 11/2017-12/2022. Clinical/treatment characteristics, lab values, and outcomes were extracted. ALC Δ RT was computed by subtracting pre-RT ALC from post-RT ALC count. Survival was modeled using Kaplan-Meier for events distributed over time, or binary logistic regression for disease response. Fisher's Exact Test or Mann-Whitney U methods were used.

RESULTS

Forty patients met inclusion criteria. Fourteen (35%) received bRT with systemic therapy. Thirty-two (80%) patients received bRT that started post-leukapheresis. bRT was delivered with a median dose of 30 Gy (range: 4-46) in 10 fractions (range: 2-23). Twenty-three patients (57.5%) had CR at 30 days post-CART infusion. Nine had PR (22.5%), and 8 patients (20%) had PD or SD. Median PFS was 8.9 months and median OS was 22 months. The pre-RT ALC mean ± SD was 0.74 ± 0.49 K/µL, and post-RT was 0.43 ± 0.35 K/µL. The absolute ALC Δ RT was 0.31 ± 0.43 K/µL, and ratio post-RT/pre-RT was 0.74 ± 0.64. Stratifying by receipt of bRT alone or with systemic therapy, there was no statistically significant difference in ALC count post-RT (chemoRT: 0.33 ± 0.23 vs. RT: 0.48 ± 0.4, p = 0.2), but there was a lower ALC count pre-RT in the chemoRT group (0.5 ± 0.3 vs. 0.87 ± 0.52 for RT alone, p = 0.02). Post-RT ALC was not significantly associated with CR/PR vs. PD/SD, or with DSS, PFS, or OS. A greater drop in ALC Δ RT trended towards association with improved 90-day response (p = 0.066), without correlation with DSS, OS, or response at 30 days. Median dose per fraction was lower among patients that got pre-leukapheresis RT (2.25 vs. 2.5, p = 0.04), but total dose of bRT or number of fractions was not significantly different. Otherwise, the groups were similar in terms of stage, disease bulk, or comprehensive vs. focal bRT. The average decrease in ALC post-RT for patients who received bRT prior to apheresis was 0.215 K/µL, compared to 0.268 K/µL for patients who received bRT post-apheresis (p = 0.75). Treatment with pre-leukapheresis bRT or ALC Δ RT among these patients were not associated with worse DFS, PFS, or OS (p>0.15).

CONCLUSION

Post-bRT ALC and reduction in ALC during bRT is not associated with worse treatment response or survival outcomes after CAR-T cell treatment in aggressive B cell lymphoma. Pre-leukapheresis bRT did not appear to substantially impact ALC, and ALC Δ RT among these patients were not associated with worse outcomes.

Selection and Prejudice: Addressing Clinical Trial Disparities With a Review of Current Shortcomings and Future Directions

Growing evidence has demonstrated significant, persistent, and widespread disparities in cancer clinical trial enrollment across myriad disease sites and target populations. Although mechanisms underlying such disparities are complex and multifactorial, clinical trial eligibility criteria may serve as a key structural barrier to equitable and diverse trial enrollment. In this review, we provide an overview of the data describing historical and current disparities in cancer clinical trial enrollment and subsequently describe several patient-, institution-, and trial-related factors which appear to be key drivers of enrollment inequity, with specific discussion regarding the impact of eligibility criteria. We further describe the landscape of ongoing professional efforts aimed at eliminating clinical trial disparities through various medical, professional, and advocacy groups. The review concludes with a practical discussion of how modernization of eligibility criteria in clinical trials may decrease or eliminate trial disparities, including specific actionable recommendations aimed at improving the quality of future eligibility criteria.

Patient Education Practices and Preferences of Interprofessional Radiation Oncology Providers

PURPOSE/OBJECTIVE(S)

Patient understanding of radiotherapy (RT) processes and data regarding optimal approaches to patient education (PE) within radiation oncology (RO) are limited. Our objective was to evaluate PE practices and preferences of interprofessional RO providers to inform recommendations for delivering inclusive, accessible, and patient-centered education.

MATERIALS/METHODS

An anonymous 17-item online survey, approved by an ethics review board, was administered to all members of the Radiation Oncology Education Collaborative Study Group (ROECSG) between 10/5/22 to 11/23/22. Respondent demographics, provider practices/preferences, and institutional practices were collected. Qualitative items explored key strategies, challenges, and desired resources for PE. Descriptive statistics summarized survey responses. Fisher's exact test compared PE practices by provider role and PE timing. Thematic analysis was used for qualitative responses.

RESULTS

A total of 123 ROECSG members, including RO attendings (64%), RO trainees (21%), medical physicists (7%), physician assistants/nurses (2%), and radiation therapists (2%), completed the survey (31% response rate). Most practiced in an academic setting (86%) in North America (82%). The most common PE resources used were custom created institution-specific (61%) and electronic health system generated materials (38%). PE was delivered primarily by one-on-one teaching (72%), paper handouts (69%), and organizational websites (21%) (e.g., RTanswers.org). Almost half (41%) reported that PE practices differed based on type of clinical encounter, for example paper handouts for in-person visits and multimedia for virtual visits. The majority (86%) stated that their institution has disease site-specific PE materials, with nearly all having breast cancer materials (91%). Only 58% reported access to non-English PE materials. RO attendings/trainees were more likely than other team members to deliver PE at consultation (98% vs 71%, p = 0.03). PE practices amongst radiation oncologists differed according to the timing along the RT care path (consultation vs simulation vs first fraction, respectively): one-on-one teaching: 89% vs 49% vs 56%, p<0.01 and paper handouts: 69% vs 28% vs 16%, p<0.01. Key PE strategies included incorporating multimedia resources, personalizing delivery, and repetition at multiple timepoints by the interprofessional team. Limited time, inadequate administrative support, and lack of customized resources were identified as challenges in PE delivery.

CONCLUSION

Interprofessional RO providers engage in PE, with most utilizing institution-specific materials. PE practices differ according to the type of clinical encounter and timing in the RT care path. Increased adoption of multimedia materials and partnerships with patients to tailor PE resources based on language, learning styles, and cultural preferences are needed to foster high-quality, patient-centered PE delivery.

Hypothyroidism following Radiotherapy for Head and Neck Cancer: A Systematic Review of the Literature and Opportunities to Improve the Therapeutic Ratio

(1) Background: Radiotherapy (RT) is a central component for the treatment of many head and neck cancers. In this systematic review of the literature, we aimed to characterize and quantify the published evidence on RT-related hypothyroidism, including estimated incidence, clinical risk factors, and dosimetric parameters that may be used to guide clinical decision making. Furthermore, we aimed to identify potential areas of improvement in the prevention and clinical management of RT-induced hypothyroidism, including the role of modern advanced therapeutic techniques. (2) Methods: We conducted a systemic review of the literature in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. PubMed and Google Scholar were searched to identify original research articles describing the incidence, mechanism, dosimetry, treatment, or prevention of radiation-related hypothyroidism for adults receiving RT for the treatment of head and neck cancers. The snowball method was used to identify additional articles. For identified articles, we tabulated several datapoints, including publication date, patient sample size, estimated hypothyroidism incidence, cancer site/type, follow-up period, radiation modality and technique, use of multimodality therapy, method of thyroid function evaluation, and proposed dosimetric predictors of hypothyroidism. (3) Results: One hundred and eleven articles met inclusion criteria, reflecting a range of head and neck cancer subtypes. There was a large variation in the estimated incidence of RT-related hypothyroidism, with a median estimate of 36% (range 3% to 79%). Reported incidence increased in later publication dates, which was likely related to improved screening and longer follow up. There were a wide variety of predictive metrics used to identify patients at high risk of hypothyroidism, the most common of which were volumetric and mean dosimetrics related to the thyroid gland (Vxx%, Dmean). More recently, there has been increasing evidence to suggest that the thyroid gland volume itself and the volume of the thyroid gland spared from high-dose radiation (VSxx) may better predict thyroid function after RT. There were no identified studies investigating the role of advanced radiotherapeutic techniques such as MRI-guided RT or particle therapy to decrease RT-related hypothyroidism. Conclusions: Hypothyroidism is a common toxicity resulting from therapeutic radiation for head and neck cancer with recent estimates suggesting 40-50% of patients may experience hypothyroidism after treatment. Dosimetric predictive models are increasingly able to accurately identify patients at risk of hypothyroidism, especially those utilizing thyroid VS metrics. Further investigation regarding the potential for advanced radiotherapeutic therapies to decrease RT-induced thyroid dysfunction is needed.

Factors Associated With Altmetric Attention Scores for Randomized Phase III Cancer Clinical Trials

PURPOSE

Altmetric Attention Scores (Altmetrics) are real-time measures of scientific impact and attention through various public outlets, including news, blogs, and social media. Herein, we aimed to describe and characterize the relationship between Altmetrics, conventional impact metrics, and features of published cancer clinical trials.

METHODS

We identified two-arm phase III cancer randomized clinical trials with a superiority end point and publication date between 2015 and 2020 from HemOnc and tabulated the following data: Altmetric, study positivity, US Food and Drug Administration (FDA) registration trial status, cancer site/category, treatment context (curative or palliative), trial design, primary end point type, experimental/control arm modality, and journal tier. We further collected conventional bibliometrics including the number of citations and relative citation ratio (RCR) for all published studies. Multiple linear regression modeling identified clinical trial factors predictive of Altmetrics, with alpha = .05 defining statistical significance.

RESULTS

Altmetrics were found for 681 (98%) of 698 publications, with a median score of 38.5 (IQR, 13-132.8). FDA registration studies (β [95% CI], 84.7 [48.8 to 120.6]; P < .001), studies reporting on curative (as opposed to palliative) interventions (-29 [-53.7 to -4.4]; P = .02), genitourinary trials (73.2 [28.1 to 118.2]; P = .001), studies published in tier 1 journals (P < .001), and those with an increased number of citations per year (0.81 [0.66 to 0.95]; P < .001) were significantly associated with increased engagement as measured by Altmetrics. Furthermore, there was a strong correlation between all collected bibliometrics and Altmetrics (R2 = 0.63, 0.68, and 0.67; P < .001 for citation count, citations per year, and RCR, respectively).

CONCLUSION

FDA registration trials describing curative interventions, studies published in traditionally defined high-impact journals, and genitourinary trial publications tend to have the greatest Altmetrics. We observed a strong relationship between Altmetrics and conventional bibliometrics. The significance and consequences of these relationships warrant further investigation.

Patient-reported Bowel Function and Bowel-related Quality of Life After Pelvic Radiation for Rectal Adenocarcinoma: The Impact of Radiation Fractionation and Surgical Resection

INTRODUCTION

Multimodality treatment for locally advanced rectal cancer (LARC) can include long-course radiotherapy (LCRT) or short course radiotherapy (SCRT). Nonoperative management is increasingly pursued for those achieving a complete clinical response. Data regarding long-term function and quality-of-life (QOL) are limited.

METHODS

Patients with LARC treated with radiotherapy from 2016 to 2020 completed the Functional Assessment of Cancer Therapy- General (FACT-G7), the Low Anterior Resection Syndrome Score (LARS) and the Fecal Incontinence QOL Scale (FIQOL). Univariate and multivariable linear regression analyses identified associations between clinical variables including radiation fractionation and the use of surgery versus non-operative management.

RESULTS

Of 204 patients surveyed, 124 (60.8%) responded. Median (interquartile range) time from radiation to survey completion was 30.1 (18.3-43) months. Seventy-nine (63.7%) respondents received LCRT, and 45 (36.3%) received SCRT; 101 (81.5%) respondents underwent surgery, and 23 (18.5%) pursued nonoperative management. There were no differences in LARS, FIQoL or FACT-G7 between patients receiving LCRT versus SCRT. On multivariable analysis, only nonoperative management was associated with lower LARS score signifying less bowel dysfunction. Nonoperative management and female sex were associated with a higher FIQoL score signifying less disruption and distress from fecal incontinence issues. Finally, lower BMI at the time of radiation, female sex, and higher FIQoL score were associated with higher FACT-G7 scores signifying better overall QOL.

CONCLUSIONS

These results suggest long-term patient-reported bowel function and QOL may be similar for individuals receiving SCRT and LCRT for the treatment of LARC, but nonoperative management may lead to improved bowel function and QOL.

Spanish Adaptation and Evaluation of Clinical Discussion Guides: Communicating the External Beam Radiotherapy Experience (CEBRE) en Español

PURPOSE

Cancer is the leading cause of death for the Hispanic/Latinx United States (US) community, which comprises 64% of the US population with limited English proficiency. Despite the common use of radiation therapy for cancer treatment, there is a dearth of radiation therapy educational materials-at appropriate reading levels-available in Spanish. To address the gap in patient-centered educational resources for communicating with Spanish-speaking patients about radiation therapy, we sought to linguistically and culturally adapt the Communicating the External Beam Radiotherapy Experience (CEBRE) clinical discussion guide series into Spanish.

METHODS AND MATERIALS

From January to December 2021, we developed and applied a stepwise methodology for Spanish adaptation of the discussion guides involving (1) professional translation; (2) interprofessional review for linguistic and cultural appropriateness and medical accuracy; (3) design review; and (4) evaluation for readability, understandability, and actionability using validated tools. We applied 4 indices for readability evaluation: Gilliam-Peña-Mountain, Läsbarhetsindex, Rate Index, and the Spanish Simple Measure of Gobbledygook. Two trained reviewers assessed understandability and actionability using the Patient Education Materials Assessment Tool.

RESULTS

After 2 revision rounds, 4 CEBRE en español discussion guides were produced through an interprofessional, iterative translation and linguistic/cultural adaptation process. Readability scores across the 4 guides ranged from 4.3 to 7.3 grade-level equivalents, thereby meeting the American Medical Association's 8th-grade standard. Patient Education Materials Assessment Tool analysis yielded near-perfect scores along understandability and actionability domains.

CONCLUSIONS

The stepwise linguistic/cultural adaptation process yielded a patient-centered guide that is appropriately readable, understandable, and actionable for Spanish-speaking patients receiving radiation therapy in the US. Future work should include an external evaluation of CEBRE en español by clinicians and patients. The methodology described can be applied to adapting resources for patient-centered communication in other fields of medicine and into other languages as part of an interprofessional approach to delivering equitable health care for all.

Factors Associated With Image-Guided Radiation Therapy Image Rejection in a Multisite Institution

PURPOSE

Nonclinical factors and cognitive biases have been shown to significantly affect clinical decision making. In this study, we aimed to identify clinical and environmental factors that might influence the decision to approve or reject image-guided radiation therapy (IGRT) images in a large multisite institution.

METHODS

We identified all IGRT image approval and rejection decisions recorded within an electronic imaging system from July 1, 2016, to June 30, 2018. For each decision, we tabulated the following parameters: the attending physician of the patient, the physician reviewing the image, total images reviewed by the physician that day, time of day, day of week, treatment site, and imaging modality (kilovoltage or cone beam computed tomography [CBCT]). We created a binary multivariable logistic regression model to identify factors associated with IGRT image rejection.

RESULTS

Overall, of 51,797 total image records evaluated, 881 (1.70%) were rejected and 50,916 (98.30%) were approved. Univariable analysis revealed that images reviewed by physicians with high rejection rates (odds ratio [OR], 3.16; P < .001) and by physicians reviewing fewer IGRT images (OR, 0.99; P = .024), images from various anatomic sites (particularly skin, breast, and head and neck), and CBCT imaging compared with kilovoltage imaging (OR, 1.49; P < .001) were associated with the increased rate of rejection. On multivariable analysis, images reviewed by physicians with high rejection rates (OR, 3.28; P < .001), images from specific anatomic sites including breast (P < .001), and CBCT imaging (P < .001) persisted as independent predictors of image rejection.

CONCLUSION

These data provide important insight into the clinical, cognitive, and environmental factors that might influence the routine clinical decision of IGRT image approval. Recognition of these factors may not only improve the quality of individual decisions but also identify opportunities for systems-based quality improvement in IGRT.

Mean Brain Dose Remains Uninfluenced by the Lesion Number for Gamma Knife Stereotactic Radiosurgery for 10+ Metastases

OBJECTIVE

Gamma Knife (GK) stereotactic radiosurgery (SRS) is increasingly used as an initial treatment for patients with 10 or more brain metastases. However, the clinical and dosimetric consequences of this practice are not well established.

METHODS

We performed a single-institution, retrospective analysis of 30 patients who received Gamma Knife SRS for 10 or more brain metastases in 1 session. We utilized MIM Software to contour the whole brain and accumulated the doses from all treated lesions to determine the mean dose delivered to the whole brain. Patient outcomes were determined from chart review.

RESULTS

Our cohort had a median number of 13 treated lesions (range 10-26 lesions) for a total of 427 treated lesions. The mean dose to the whole brain was determined to be 1.8 ± 0.91 Gy (range 0.70-3.8 Gy). The mean dose to the whole brain did not correlate with the number of treated lesions (Pearson r = 0.23, P = 0.21), but was closely associated with tumor volume (Pearson r = 0.95, P < 0.0001). There were no significant correlations between overall survival and number of lesions or aggregate tumor volume. Fourteen patients (47%) underwent additional SRS sessions and 6 patients (20%) underwent whole-brain radiotherapy with a median of 6.6 months (range 3.0-50 months) after SRS. Two patients (6.6%) developed grade 2 radionecrosis following SRS beyond earlier whole-brain radiotherapy.

CONCLUSION

The mean dose to the whole brain in patients treated with Gamma Knife SRS for 10 or more brain metastases remained low with an acceptable rate of radionecrosis. This strategy allowed the majority of patients to avoid subsequent whole-brain radiotherapy.

Cancer Informatics 2022: Real-World Data Yields Important Insights into the Conduct of Clinical Trials and Registries

OBJECTIVE

To summarize significant research contributions on cancer informatics published in 2021.

METHODS

An extensive search using PubMed/MEDLINE and Altmetric scores was conducted to identify the scientific contributions published in 2021 that address topics in cancer informatics. The selection process comprised three steps: (i) 15 candidate best papers were first selected by the two section editors, (ii) external reviewers from internationally renowned research teams reviewed each candidate best paper, and (iii) the final selection of two best papers was conducted by the editorial board of the IMIA Yearbook.

RESULTS

The two selected best papers demonstrate some of the promises and shortcomings of real-world data.

CONCLUSION

Cancer informatics is a maturing subfield of biomedical informatics. Applications of informatics methods to real-world data are especially notable in 2021.

Linguistic Biases in Letters of Recommendation for Radiation Oncology Residency Applicants from 2015 to 2019

We aimed to investigate whether implicit linguistic biases exist in letters of recommendation (LORs) for applicants to radiation oncology (RO) residency. LORs (n = 487) written for applicants (n = 125) invited to interview at a single RO residency program from the 2015 to 2019 application cycles were included for analysis. Linguistic Inquiry and Word Count (LIWC) software was used to evaluate LORs for length and a dictionary of predetermined themes. Language was evaluated for gender bias using a publicly available gender bias calculator. Non-parametric tests were used to compare linguistic domain scores. The median number of the LORs per applicant was 4 (range 3-5). No significant differences by applicant gender were detected in LIWC score domains or gender bias calculator (P > 0.05). However, LORs for applicants from racial/ethnic backgrounds underrepresented in medicine were less likely to include standout descriptors (P = 0.008). Male writers were less likely to describe applicant characteristics related to patient care (P < 0.0001) and agentic personality (P = 0.006). LORs written by RO were shorter (P < 0.0001) and included fewer standout descriptors (P = 0.014) but were also more likely to include statements regarding applicant desirability (P = 0.045) and research (P = 0.008). While language was globally male-biased, assistant professors were less likely than associate professors (P = 0.0064) and full professors (P = 0.023) to use male-biased language. Significant linguistic differences were observed in RO residency LORs, suggesting that implicit biases related to both applicants and letter writers may exist. Recognition, and ideally eradication, of such biases are crucial for fair and equitable evaluation of a diverse applicant pool of RO residency candidates.

Exclusion of Older Adults from Cancer Clinical Trials: Review of the Literature and Future Recommendations

In this review, we present the context of older adult (OA) cancer patients within the broader cancer population, including cancer burdens and trial representation. We first describe the proportion of older adults in clinical trials, with studies showing strong evidence that the proportion of OA in cancer trials is much less than the proportion of OA in the overall cancer population. We highlight the lack of generalizability that can lead to challenges in treatment decisions for OA as well as concerns regarding health inequity. We then discuss barriers to OA enrollment related to trial structure and design, physician perspective, and patient and/or caregiver perspective. We expand on this further by outlining these barriers throughout the process of trial design, patient enrollment/trial implementation, and data analysis in post-market settings. We summarize guidelines from national societies, regulatory agencies, and other institutional bodies, then present a compilation of on-the-ground actionable recommendations to address the challenges of clinical trial design, focusing on geriatric assessments and OA-specific trials. We conclude by providing an outline for future directions, noting specifically the potential impact that radiotherapy and radiation oncology may have on clinical trials related to OA patients.

Trends in Publication Speed of Radiation Oncology Research from 2010 to 2019

Purpose

In this investigation, we aimed to describe trends in time to acceptance (TTA) and time to online publication (TTOP) of research published in leading radiation oncology journals from 2010 to 2019. We further sought to identify journal characteristics that might influence TTA and TTOP.

Methods and Materials

We searched the publication history of 5 leading international radiation oncology journals. For all research articles accepted from January 1, 2010, to December 31, 2019, we tabulated the date of article receipt, the date of acceptance, and the date of online publication when available. The TTA was calculated as the number of elapsed days from article receipt to acceptance, and the TTOP was calculated as the number of elapsed days from article acceptance to online publication. Using the Mann-Kendall test, we assessed for monotonic trends over time and used the post hoc Theil-Sen method to estimate rates of change. We created a multiple regression model to identify journal characteristics associated with TTA and TTOP.

Results

In total, 10,132 articles were included. Both the TTA and the TTOP decreased significantly from 2010 to 2019 (P = .005 and P < .001, respectively), with an estimated decrease of 1.5 days per year for the TTA and 7.0 days per year for the TTOP. Multiple regression modeling revealed that a higher journal impact factor was independently associated with an increased TTA (P < .001) and a decreased TTOP (P < .001). A higher number of accepted journal articles per year was associated with a decreased TTA (P < .001) and an increased TTOP (P < .001).

Conclusions

Radiation oncology research has been accepted and published online at increasingly faster rates during the past decade. The TTA may be longer in higher-impact, more selective journals, possibly suggesting a need for comprehensive peer review and complex editorial decisions. However, these articles are also published online faster after article acceptance. Future work examining patterns of acceptance and publication speed is needed to encourage rapid dissemination of practice-guiding data.

Benchmarking Outcomes after Ablative Radiotherapy for Molecularly Characterized Intrahepatic Cholangiocarcinoma

We have previously shown that ablative radiotherapy (A-RT) with a biologically effective dose (BED10) ≥ 80.5 Gy for patients with unresectable intrahepatic cholangiocarcinoma (ICC) is associated with longer survival. Despite recent large-scale sequencing efforts in ICC, outcomes following RT based on genetic alterations have not been described. We reviewed records of 156 consecutive patients treated with A-RT for unresectable ICC from 2008 to 2020. For 114 patients (73%), next-generation sequencing provided molecular profiles. The overall survival (OS), local control (LC), and distant metastasis-free survival (DMFS) were estimated using the Kaplan-Meier method. Univariate and multivariable Cox analyses were used to determine the associations with the outcomes. The median tumor size was 7.3 (range: 2.2-18.2) cm. The portal vein thrombus (PVT) was present in 10%. The RT median BED10 was 98 Gy (range: 81-144 Gy). The median (95% confidence interval) follow-up was 58 (42-104) months from diagnosis and 39 (33-74) months from RT. The median OS was 32 (29-35) months after diagnosis and 20 (16-24) months after RT. The one-year OS, LC, and intrahepatic DMFS were 73% (65-80%), 81% (73-87%), and 34% (26-42%). The most common mutations were in IDH1 (25%), TP53 (22%), ARID1A (19%), and FGFR2 (13%). Upon multivariable analysis, the factors associated with death included worse performance status, larger tumor, metastatic disease, higher CA 19-9, PVT, satellitosis, and IDH1 and PIK3CA mutations. TP53 mutation was associated with local failure. Further investigation into the prognostic value of individual mutations and combinations thereof is warranted.

Representation of Women in the Leadership Structure of the US Health Care System

This cross-sectional study evaluates the gender distribution among chief executives and senior leaders at US health care organizations.

Single Fraction Radiation for Myeloid Sarcoma Is as Effective as Multi-Fraction Regimens for Tumor Regression and Control

INTRODUCTION/BACKGROUND

Myeloid sarcoma is a rare extramedullary manifestation of immature myeloid/monocyte cells. Radiotherapy (RT) yields good local control, but data on different fractionation schemes are limited. The goal of this retrospective study was to share our institutional experience and assess volumetric regression with differential fractionation.

MATERIALS AND METHODS

We evaluated patients treated for myeloid sarcoma between 2000 and 2019 and categorized them into Group A (treated with RT) and Group B (no RT). We assessed local control using cumulative incidence function analysis. Post-treatment imaging sequences were analyzed for volumetric calculations.

RESULTS

Forty-four patients with 80 lesions were assessed. Twenty-three patients with 52 lesions received RT (Group A), and 6 lesions received a single fraction of RT. There were 2 instances of local progression in Group A and 8 in Group B, with a cumulative incidence function estimate of local progression in Group A of 2.4% at 1 year and 6.9% at 2 years, significantly reduced compared to 29.7% and 35.5% in Group B, respectively (hazard ratio 0.13 [95% confidence interval 0.030.63], P = .011). No lesion treated with a single fraction of RT developed local progression. Volumetric analysis for 19 chronologically followed lesions (including 3 treated with a single fraction) revealed no difference in regression between single or multi-fraction treatment.

CONCLUSION

RT for myeloid sarcoma yields excellent local control and may be as effective in a single fraction as more protracted courses, though this requires validation. For a diagnosis associated with poor survival, a single palliative fraction may be optimal with potential for higher utilization.

Mentorship Initiatives in Radiation Oncology: A Scoping Review of the Literature

PURPOSE

Although mentorship is described extensively in academic medical literature, there are few descriptions of mentorship specific to radiation oncology. The goal of the current study was to investigate the state of mentorship in radiation oncology through a scoping review of the literature.

METHODS AND MATERIALS

A search protocol was defined according to Preferred Reporting Items for Systematic Reviews and Meta Analyses extension for scoping reviews (PRISMA-ScR) guidelines. Predefined search terms and medical subject headings were used to search PubMed for English language articles published after January 1, 1990, on mentorship in radiation oncology. Additionally, in-press articles from major radiation oncology and medical education journals were searched. Three reviewers determined article eligibility. Included articles were classified based on predefined evaluation criteria.

RESULTS

Fourteen publications from 2008 to 2019 met inclusion criteria. The most commonly described form of mentorship was the dyad (64.3%), followed by team (14.3%) and peer (7.1%); 2 articles did not specify mentorship type (14.3%). The most commonly mentored participants were residents (35.7%), followed by medical students (35.7%) and attendings (21.4%); 1 study included participants of all levels (7.1%). Thirteen studies (92.9%) identified an experimental study design, most of which were cross-sectional (42.9%), followed by cohort studies (28.6%) and before/after (21.4%). Median sample size, reported in 12 of 13 experimental studies, was 132 (coefficient of variation, 1.06). Although outcomes varied widely, the majority described successful implementation of mentorship initiatives with high levels of participant satisfaction.

CONCLUSIONS

Although few initiatives are currently reported, the present study suggests that these initiatives are successful in promoting career development and increasing professional satisfaction. The interventions overwhelmingly described mentorship dyads; other forms of mentorship are either less common or understudied. Limitations included interventions not being evaluated in a controlled setting, and many were assessed using surveys with low response rates. This review highlights rich opportunities for future scholarship to develop, evaluate, and disseminate radiation oncology mentorship initiatives.

Readability of Patient Education Materials From High-Impact Medical Journals: A 20-Year Analysis

Comprehensive patient education is necessary for shared decision-making. While patient–provider conversations primarily drive patient education, patients also use published materials to enhance their understanding. In this investigation, we evaluated the readability of 2585 patient education materials published in high-impact medical journals from 1998 to 2018 and compared our findings to readability recommendations from national groups. For all materials, mean readability grade levels ranged from 11.2 to 13.8 by various metrics. Fifty-four (2.1%) materials met the American Medical Association recommendation of sixth grade reading level, and 215 (8.2%) met the National Institutes of Health recommendation of eighth grade level. When stratified by journal and material type, general medical education materials from Annals of Internal Medicine were the most readable (P < .001), with 79.8% meeting the eighth grade level. Readability did not differ significantly over time. Efforts to standardize publication practice with the incorporation of readability evaluation during the review process may improve patients’ understanding of their disease processes and treatment options.

Patterns of Care and Survival Outcomes for Odontogenic Cancers

OBJECTIVES

Our understanding of odontogenic cancers is limited primarily to case studies given the rarity of these head and neck neoplasms. Using the National Cancer Database, we report the treatment patterns and survival outcomes for one of the largest cohorts of patients with odontogenic cancers.

METHODS

Patients with odontogenic tumors who did not have metastatic disease and received at least part of their care at the reporting facility were included. Patient and treatment variables were assessed using logistic regression. Survival was assessed using Cox proportional hazard models.

RESULTS

We identified 437 patients with odontogenic cancers, the majority of which had malignant ameloblastoma (n = 203) or odontogenic carcinoma (n = 217). Median follow-up was 44.8 months. On multivariate analysis, improved survival was associated with age <57 years (Hazard ratios [HR] 0.44, P = .012), lower comorbidity scores (HR 0.40, P = .008), surgical resection (HR 0.08, P < .001) and absence of lymph node metastasis (HR 0.23, P < .001). The 5-year overall survival was 87.1% for debulking surgery, 88.6% for radical resection and 26.6% for no surgical resection (P < .001). Lymph node metastases were associated with tumor size ≥5 cm (P = .006), malignant odontogenic histology (P = .025), and moderate/poor differentiation (P < .001).

CONCLUSION

In this large series of odontogenic cancers, any type of surgical resection was associated with improved survival. Lymph node metastases, although infrequent, were associated with significantly worse survival.

LEVEL OF EVIDENCE

Level 3 Laryngoscope, 131:E1496-E1502, 2021.

Three-dimensional printing in radiation oncology: A systematic review of the literature

Purpose/objectives

Three‐dimensional (3D) printing is recognized as an effective clinical and educational tool in procedurally intensive specialties. However, it has a nascent role in radiation oncology. The goal of this investigation is to clarify the extent to which 3D printing applications are currently being used in radiation oncology through a systematic review of the literature.

Materials/methods

A search protocol was defined according to preferred reporting items for systematic reviews and meta‐analyses (PRISMA) guidelines. Included articles were evaluated using parameters of interest including: year and country of publication, experimental design, sample size for clinical studies, radiation oncology topic, reported outcomes, and implementation barriers or safety concerns.

Results

One hundred and three publications from 2012 to 2019 met inclusion criteria. The most commonly described 3D printing applications included quality assurance phantoms (26%), brachytherapy applicators (20%), bolus (17%), preclinical animal irradiation (10%), compensators (7%), and immobilization devices (5%). Most studies were preclinical feasibility studies (63%), with few clinical investigations such as case reports or series (13%) or cohort studies (11%). The most common applications evaluated within clinical settings included brachytherapy applicators (44%) and bolus (28%). Sample sizes for clinical investigations were small (median 10, range 1–42). A minority of articles described basic or translational research (11%) and workflow or cost evaluation studies (3%). The number of articles increased over time (P < 0.0001). While outcomes were heterogeneous, most studies reported successful implementation of accurate and cost‐effective 3D printing methods.

Conclusions

Three‐dimensional printing is rapidly growing in radiation oncology and has been implemented effectively in a diverse array of applications. Although the number of 3D printing publications has steadily risen, the majority of current reports are preclinical in nature and the few clinical studies that do exist report on small sample sizes. Further dissemination of ongoing investigations describing the clinical application of developed 3D printing technologies in larger cohorts is warranted.

Evaluation of patient education materials for stereotactic radiosurgery from high-performing neurosurgery hospitals and professional societies

Background

Little is known about the readability and utility of patient education materials for stereotactic radiosurgery (SRS). Therefore, the goal of this investigation was to evaluate such materials from high-performing neurosurgery hospitals and professional societies through an analysis of readability and educational content.

Methods

In this cross-cross sectional study, 61 websites associated with the top 50 neurosurgery and neurology hospitals according to U.S. News & World Report (USNWR) and 11 predetermined professional medical societies were queried. Identified SRS education materials were analyzed by 6 readability indices. Educational content was assessed by 10 criteria based on surveys of patients' perspectives about SRS.

Results

Fifty-four materials were identified from the target population (45 from USNWR hospital websites and 9 from professional society websites). Mean readability of materials ranged from 11.7 to 15.3 grade level, far more difficult than national recommendations of sixth and eighth grade. Materials were found to have deficiencies in educational content. Compared with high-performing hospitals, materials from websites of professional societies were longer (P = .002), and more likely to discuss risks and benefits specific to SRS (P = .008), alternative treatment options (P = .05) and expected outcomes or postprocedure descriptions (P = .004). Hospital materials were also more likely to favor brand-specific terminology (eg, GammaKnife) over generic terminology (eg, radiosurgery; P = .019).

Conclusion

Publicly available online patient educational materials for SRS are written at reading levels above national recommendations. Furthermore, many lack information identified as important by patients. Reevaluation and improvement of online SRS educational materials on a national scale are warranted.

Patterns of Care and Outcomes of Intensity-Modulated Radiotherapy and 3D Conformal Radiotherapy for Early Stage Glottic Cancer: A National Cancer Database Analysis

Early stage glottic cancer has traditionally been treated with 3D conformal radiotherapy (3DCRT). However, intensity-modulated radiotherapy (IMRT) has been recently adopted as an alternative to decrease toxicity. Here, we compared the usage and outcomes of IMRT and 3DCRT for patients with early stage squamous cell carcinoma (SCC) of the glottic larynx. Using the National Cancer Database, we identified patients with Stage I–II SCC of the glottis who received 55–75 Gy using IMRT (n = 1623) or 3DCRT (n = 2696). Median follow up was 42 months with a 5-year overall survival (OS) of 72%. Using a nominal logistic regression, race, ethnicity, year of diagnosis and fraction size were associated with the receipt of IMRT (p < 0.05). Using Kaplan–Meier methods and Cox proportional hazards models as well as a propensity matched cohort, there was no difference in OS for patients who received IMRT versus 3DCRT (hazard ratio (HR), 1.08; 95% confidence interval (95% CI), 0.93–1.26; p = 0.302). However, there was a survival benefit for patients receiving slight hypofractionation as compared to conventional fractionation (HR, 0.78; 95% CI, 0.69–0.92; p = 0.003). IMRT was associated with similar survival as 3DCRT, supporting the implementation of this potentially less toxic modality without compromising survival.

CMET-11. RESPONSE TO STEREOTACTIC RADIOSURGERY FOR MULTIPLE BRAIN METASTASES BASED ON HISTOLOGY-SPECIFIC SUBTYPE STATUS

BACKGROUND

This retrospective study evaluated the relationship between histologic subtype and treatment outcomes following SRS for the treatment of multiple brain metastases (MBM).

METHODS

We analyzed patients with MBM, defined here as >= 3 lesions, treated with SRS at our institution. Primary histologies examined were NSCLC, breast, and melanoma. Patients were categorized according to histology-specific subtypes (NSCLC-EGFR, ALK, KRAS, PD-L1%; breast-HER2, ER, PR; melanoma-BRAF). The primary outcome was local control (defined by RANO-BM) and secondary outcomes included intracranial progression-free survival (iPFS) and overall survival (OS).

RESULTS

141 patients met inclusion criteria (66 NSCLC, 61 breast, and 14 melanoma). HER2+ and BRAF V600E+ lesions had increased rates of local control following SRS (P=0.0048 and P=0.0256, respectively) compared to other breast/melanoma subtypes. EGFR mutation was not associated with increased local control with SRS (71 vs 74%), but increased iPFS (P=0.0031). On multivariable analysis, EGFR+ was independently associated with a decreased time-dependent risk of death (P=0.011). The use of progressively newer generations of EGFR-directed therapies was associated with stepwise decreasing risk of intracranial progression and death. HER2+ disease had improved iPFS and OS (P=0.0058 and P< 0.0001, respectively; it was not an independent risk factor for progression or death; however, the use of HER2-directed antibodies was associated with decreased risk of death (p=0.036). The use of tyrosine kinase inhibitors (i.e. lapatanib) was not associated with improvements, although this was a small subset.

CONCLUSIONS

Some histologic subtypes appear to have better control with SRS, with HER2+ breast cancer and BRAF V600E+ melanoma associated with improved outcomes – this requires further validation; a volumetric analysis is pending. This the protective effect of EGFR mutation appears to be partly related to use of EGFR inhibitors, with the use of newer-generation therapies leading to improved outcomes; although local control with SRS remains excellent regardless of the mutation.

RDNA-05. RADIOTHERAPY PROMOTES ONCOPROGRESSIVE CROSSTALK BETWEEN GLIOBLASTOMA TUMOR CELLS AND M2 MACROPHAGES VIA THE NLRP3 INFLAMMASOME PATHWAY

PURPOSE

Radiotherapy (RT) is an essential component in the adjuvant treatment of glioblastoma (GBM); however, despite an initial benefit in tumor control, recurrence is nearly universal. The inflammasome is a multimeric cytosolic complex that has been shown to be activated in immune cells following RT. We investigated the relationship of inflammasome activation and disease progression after RT in GBM.

METHODS

We performed survival analysis for patients with recurrent GBM using the TCGA dataset, stratifying according to expression of inflammasome pathway molecules Caspase 1 (CASP1), IL-1β, and NLRP3. IL-1β expression and colocalization with CD11b+ myeloid cells were analyzed at different time points following RT in a murine glioma GL261 model. We detected the secreted IL-1β, CASP1 activity, and NLRP3 expression in both tumor and infiltrating immune cells, and the downstream effects of their interplay, including cellular apoptosis, proliferation, and viability.

RESULTS

High expression of CASP1, IL-1β, and NLRP3 are associated with poor survival in recurrent GBM. In a mouse model, recurrent tumors after treatment with RT display higher levels of the inflammasome effector molecule IL-1β, which colocalizes with infiltrating CD11b+ myeloid cells. Using a co-culture system of tumor cell and M2 macrophages, we found that RT enhances inflammasome activation in both cell types, and this interaction restores the proliferative capacity of surviving tumor cells following treatment. RT induces the inflammasome pathway activation in the setting of an associated immune microenvironment rich in tumor-associated macrophages and myeloid-derived suppressor cells (TAM/MDSCs) and not in tumor cells alone.

CONCLUSIONS

Inhibition of the oncoprogressive crosstalk between GBM tumor cells and M2 macrophages, possibly through disruption of the inflammasome pathway, might be a potential therapeutic strategy with RT.

Assessment of Use, Specificity, and Readability of Written Clinical Informed Consent Forms for Patients With Cancer Undergoing Radiotherapy

Importance

Appropriate informed consent processes are crucial to preservation of patient autonomy and shared decision making. Although half of patients with cancer receive radiotherapy, it is unknown whether current consent practices are comprehensible for patients.

Objective

To characterize use, specificity, and readability of clinical informed consent forms for radiotherapy, hypothesizing that forms would be higher than the recommended sixth- to eighth-grade readability level.

Design, Setting, and Participants

This nationwide cross-sectional survey study and readability analysis was conducted from 2016 to 2018 and included 89 academic radiation oncology departments that were part of the 2016 Electronic Residency Application Service. Department leaders (clinical directors, chairs, and personal contacts of study authors) at academic radiation oncology departments were contacted via email.

Main Outcomes and Measures

Readability levels were measured by 7 validated readability indices, including the Ford, Caylor, Sticht (FORCAST) index for nonnarrative texts. Difficult words were identified using The Living Word Vocabulary, which describes the readability grade levels of 40 000 common words.

Results

Of 89 departments, 67 (75%) responded to questions and 57 (64%) provided 113 forms for analysis. Departments providing forms did not differ substantially from others in terms of region, residency size, research output, rural vs urban location, or public vs private institution status. All departments obtained patient written informed consent before radiotherapy; 38 (57%) used body site-specific forms. Using the most conservative (low-score) estimate, mean form readability ranged from grade level 10.6 to 14.2. By 7 distinct indices, only 9 (8%) of 113 forms met the recommended eighth-grade readability level, and 4 (4%) forms met a sixth-grade level. Not a single form met either recommendation based on the FORCAST index. Forms used an average of 7.2 difficult words. Body site-specific forms had considerably better readability than general consent forms.

Conclusions and Relevance

This nationwide study of informed consent practices for cancer treatment with radiotherapy demonstrates that while all US academic radiotherapy departments use written consent forms, it is rare for templates to meet the recommended readability levels for patient materials. These data suggest the need for reevaluation and modification of the approach to radiotherapy consent, ideally with guidance and templates designed by national professional organizations.

Readability of Patient Education Materials in Radiation Oncology-Are We Improving?

PURPOSE

Prior research suggests that patient education materials on radiation therapy from various professional groups are written at reading levels above national recommendations of sixth to eighth grade. Since publication of these initial findings, many materials from these sources have been updated or newly created. However, the extent to which readability was considered in the design of these new documents remains unknown. Therefore, the goal of this investigation was to evaluate readability of online education materials for radiation therapy, comparing readability of updated materials with those included in the previous study.

METHODS AND MATERIALS

Patient education materials related to radiation oncology were identified from websites of the 3 professional societies used in the original investigation (the American College of Radiology, the American Cancer Society, and the American Society for Radiation Oncology). The documents included in the first analysis were used as a comparator. To allow for accurate evaluation across groups, materials were matched by content; when necessary, documents were combined from the original cohort to create topically equivalent materials to reflect those currently available on society websites. Identified materials were analyzed using 7 validated readability indices, and results are reported in grade-level equivalents. Original materials were also reanalyzed with the same method.

RESULTS

American Cancer Society materials had the lowest average baseline levels (9.4-11.3 grade level) and showed improved readability in the more recent materials (8.0-10.5 grade level). By contrast, the American Society for Radiation Oncology materials had high average baseline readability levels (11.1-13.9 grade level) that actually worsened in the more recent materials (11.7-16.2 grade level). The number of documents meeting national recommendations did not improve in the updated cohort.

CONCLUSION

Despite evidence that readability levels of patient education materials in radiation oncology are unacceptably high, the readability of newly created materials is not consistently improving across professional societies. Although certain groups may incorporate readability in the design of educational documents, more consistent consideration across all organizations is needed.

Simulation as More Than a Treatment-Planning Tool: A Systematic Review of the Literature on Radiation Oncology Simulation-Based Medical Education

PURPOSE

Simulation-based medical education (SBME) is gaining prominence as a tool to meet Accreditation Council for Graduate Medical Education-mandated competency-based assessment educational goals. SBME is used in radiation oncology, although the type and extent are not clear. This study reports a systematic literature review designed to clarify the type and extent of radiation oncology SBME.

METHODS AND MATERIALS

The systematic review focused on radiation oncology SBME literature. The methods followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The inclusion criteria were identified according to the PICOS (population, intervention, comparison, outcome, and setting) framework. The population included undergraduate, graduate, and continuing medical education learners. Studies were limited to English-language studies published on or after January 1, 1990, in peer-reviewed journals. PubMed, MedEdPORTAL, and in-press articles were searched. The PubMed search was conducted using predefined search terms. References and similar articles were examined. Medical Subject Headings terms in selected articles were reviewed to ensure relevant terms were included.

RESULTS

Fifty-four SBME publications met the inclusion criteria. Only 9 of 54 studies (17%) self-identified as SBME. SBME types included screen-based simulators (56%), simulated environments (13%), virtual reality and haptic systems (13%), simulated patients (11%), part-task trainers (6%), and computer-based systems with mannequins (2%). A variety of radiation oncology skill sets were addressed, including contouring (54%), treatment planning (20%), clinical decision making (17%), anatomy and/or radiology (13%), radiation biology and/or physics (13%), communication skills and/or patient education (13%), brachytherapy (13%), and immobilization (11%). A target learning population was defined in 47 studies, including residents (53%), attending physicians (36%), medical students (21%), medical physicists (11%), radiation therapists (9%), nurses (6%), administrative staff (4%), and dosimetrists (4%). Learner feedback was reported in 32 studies.

CONCLUSIONS

Overall, this systematic literature review provides context and guidance for future radiation oncology SBME development. Appropriately framing SBME reports in the radiation oncology literature will facilitate development, implementation, and evaluation of SBME interventions. SBME resources should be centralized to facilitate dissemination and share resources.