Primary Stereotactic Body Radiotherapy for Spinal Bone Metastases From Lung Adenocarcinoma.

OBJECTIVE: This study aimed to assess the results of primary stereotactic body radiotherapy (SBRT) for spinal bone metastases (SBM) originating from lung adenocarcinoma (ADC). We considered the revised Tokuhashi score (rTS), Spinal Instability Neoplastic Score (SINS), and genetic characteristics. METHODS: We examined adult patients with lung ADC who underwent primary SBRT (using the CyberKnife System) for SBM between March 2012 and January 2023. RESULTS: We analyzed data from 99 patients, covering 152 SBM across 194 vertebrae. The overall local control (LC) rate was 77.6% for SBM from lung ADC, with a LC rate of 90.7% at 1 year. The median period for local progression (LP) occurrence was recorded at 10.0 (3-52) months. Additionally, Asian patients demonstrated higher LC rates than White patients. Utilizing the rTS and SINS as predictive tools, we revealed that a poor survival prognosis and an unstable spinal structure were associated with increased rates of LP. Furthermore, the presence of osteolytic bone destructions and pain complaints were significantly correlated with the occurrence of LP. In the cohort of this study, 108 SBM underwent analysis to determine the expression levels of programmed cell death ligand 1 (PD-L1). Additionally, within this group, 60 showed mutations in the epidermal growth factor receptor (EGFR) alongside PD-L1 expression. Nevertheless, these genetic differences did not result in statistically significant differences in the LC rate. CONCLUSION: The one-year LC rate for primary SBRT targeting SBM from lung ADC stood at 90.7%, particularly with the use of the CyberKnife System. Patients achieving LC exhibited significantly longer survival times compared to those with LP.

Where Does Auto-Segmentation for Brain Metastases Radiosurgery Stand Today?

Detection and segmentation of brain metastases (BMs) play a pivotal role in diagnosis, treatment planning, and follow-up evaluations for effective BM management. Given the rising prevalence of BM cases and its predominantly multiple onsets, automated segmentation is becoming necessary in stereotactic radiosurgery. It not only alleviates the clinician's manual workload and improves clinical workflow efficiency but also ensures treatment safety, ultimately improving patient care. Recent strides in machine learning, particularly in deep learning (DL), have revolutionized medical image segmentation, achieving state-of-the-art results. This review aims to analyze auto-segmentation strategies, characterize the utilized data, and assess the performance of cutting-edge BM segmentation methodologies. Additionally, we delve into the challenges confronting BM segmentation and share insights gleaned from our algorithmic and clinical implementation experiences.

Performance Analysis of a Radiation Oncology Educational Podcast.

PURPOSE: Asynchronous podcast education is a popular supplementary tool, with up to 88% of medical residents reporting its use. Radiation oncology podcasts remain scarce. The authors analyzed the early performance, listenership, and engagement of the first education-specific radiation oncology medical podcast. METHODS: Episode data and listener demographics were gathered from Spotify and Apple Podcasts. Episodes were case based, categorized by disease subsite, and reviewed by a board-certified radiation oncologist. Listenership was defined by the number of plays per day (ppd) on unique devices, averaged up to 60 days from publication. Episode engagement was defined as a percentage of plays on unique devices playing >40% of an episode within a single session. Quantitative end points included episode engagement and listenership. Pearson's correlation coefficient calculations were used for analysis. RESULTS: From July 2022 to March 2023, 20 total episodes had 13,078 total plays over 227 days. The median episode length was 13.8 min (range, 9.2-20.1 min). Listener demographics were as follows: 54.4% men, 44.0% women, 1.3% not specified, and 0.3% nonbinary, with ages 18 to 22 (1%), 23 to 27 (13%), 28 to 34 (58%), 35 to 44 (22%), 45 to 59 (4%), and ≥60 (2%) years. Episodes were played in 53 countries, with the most plays in North America (71.5%), followed by Asia (10.2%), Europe (8.2%), Oceania (8.0%), Africa (1.5%), and South America (0.5%). There was a 585.2% increase in listenership since initiation, with median growth of 46.0% per month. Median listenership and engagement were 11.3 ppd (interquartile range, 10.3-13.8 ppd) and 81.4% (interquartile range, 72.0%-84.2%) for all episodes, respectively. A significant negative relationship between episode length and engagement was observed (r[20] = -0.51, P = .02). There was no statistically significant relationship between ppd and episode length (r[20] = -0.19, P = .42). CONCLUSIONS: The significant rise in listenership, high episode engagement, and large international audience support a previously unmet need in radiation oncology medical education that may be supplemented by podcasts.

Patterns of Recurrence After Poor Response to Neoadjuvant Chemotherapy in Gastric Cancer and the Role for Adjuvant Radiation.

BACKGROUND: Improved treatment strategies are needed for patients with locally advanced gastric cancer with poor response to neoadjuvant chemotherapy. We aimed to describe patterns of failure for patients with no or partial response (NR, PR) to preoperative chemotherapy. PATIENTS AND METHODS: We analyzed patients with locally advanced gastric cancer treated from 2008 to 2022 with preoperative chemotherapy followed by surgery with D2 resection. We excluded patients who received radiation. Cumulative incidence of locoregional failure (LRF) and distant metastases (DM) were calculated. For patients with recurrent abdominal disease, hypothetical radiation clinical treatment volumes (CTV) were contoured on postoperative scans and compared with patterns of recurrence. RESULTS: A total of 60 patients were identified. The most used preoperative chemotherapy was FLOT (38.6%), followed by FOLFOX (30%) and ECF/ECX/EOX (23.3%). Four (6.7%), 40 (66.7%), and 9 patients (15%) had a complete pathologic response (CR), PR, and NR to neoadjuvant therapy, respectively. Among patients without a CR, 3-year overall and progression-free survival rates were 62.3% (95% CI 48-76.6%) and 51.3% (95% CI 36.9-65.7%), respectively. Three-year cumulative incidence of LRF and DM were 8.4% (95% CI 0.4-16.4%) and 41.0% (95% CI 26.3-55.4%), respectively. Absolute rates of patients having the first site of recurrence encompassed by a postoperative radiation CTV was 2.0% for patients without a CR and 0% for patients with NR. CONCLUSIONS: Patients with locally advanced gastric cancer with less than a CR to chemotherapy have poor outcomes due to high rates of DM. Adjuvant locoregional therapy such as radiation is unlikely to affect survival.

Lessons and Opportunities for Biomarker-Driven Radiation Personalization in Head and Neck Cancer.

Head and neck cancer is notoriously challenging to treat in part because it constitutes an anatomically and biologically diverse group of cancers with heterogeneous prognoses. While treatment can be associated with significant late toxicities, recurrence is often difficult to salvage with poor survival rates and functional morbidity.1,2 Thus, achieving tumor control and cure at the initial diagnosis is the highest priority. Given the differing outcome expectations (even within a specific sub-site like oropharyngeal carcinoma), there has been growing interest in personalizing treatment: de-escalation in selected cancers to decrease the risk of late toxicity without compromising oncologic outcomes, and intensification for more aggressive cancers to improve oncologic outcomes without causing undue toxicity. This risk stratification is increasingly accomplished using biomarkers, which can represent molecular, clinicopathologic, and/or radiologic data. In this review, we will focus on biomarker-driven radiotherapy dose personalization with emphasis on oropharyngeal and nasopharyngeal carcinoma. This radiation personalization is largely performed on the population level by identifying patients with good prognosis via traditional clinicopathologic factors, although there are emerging studies supporting inter-tumor and intra-tumor level personalization via imaging and molecular biomarkers.

Radiation Oncology Virtual Education Rotation (ROVER) 2.0 for Residents: Implementation and Outcomes.

The COVID-19 pandemic catalyzed the integration of a virtual education curriculum to support radiation oncologists in training. We report outcomes from Radiation Oncology Virtual Education Rotation (ROVER) 2.0, a supplementary virtual educational curriculum created for radiation oncology residents globally. A prospective cohort of residents completed surveys before and after the live virtual webinar sessions (pre- and post-surveys, respectively). Live sessions were structured as complex gray-zone cases across various core disease sites. Resident demographics and responses were summarized using means, standard deviations, and proportions. Nine ROVER sessions were held from October 2020 to June 2021. A total of 1487 registered residents completed the pre-survey, of which 786 attended the live case discussion and 223 completed post-surveys. A total of 479 unique radiation oncology residents (of which 95, n = 19.8%, were international attendees) from 147 institutions (national, n = 81, 55.1%; international, n = 66, 44.9%) participated in the sessions. There was similar participation across post-graduate year (PGY) 2 through 5 (range n = 86 to n = 105). Of the 122 unique resident post-surveys, nearly all reported learning through the virtual structure as "very easy" or "easy" (97.5%, n = 119). A majority rated the ROVER 2.0 educational sessions to be "valuable or "very valuable" (99.2%, n = 121), and the panelists-attendee interaction as "appropriate" (97.5%, n = 119). Virtual live didactics aimed at radiation oncology residents are feasible. These results suggest that the adoption of the ROVER 2.0 curricula may help improve radiation oncology resident education.

Post-operative Stereotactic Radiosurgery of Malignant Melanotic Schwannoma.

Melanotic schwannoma is an extremely rare schwannoma variant with malignant potential, demonstrating high local and distant recurrence. Given the paucity of data, recommended treatment with localized disease is radical resection, with the unclear benefit of adjuvant therapy. We present a case of an 18-year-old female with no past medical history or genetic syndromes who underwent margin-positive resection of an S1 nerve root melanotic schwannoma followed by adjuvant stereotactic radiosurgery (SRS). SRS was delivered without acute or late toxicity by 2.5 years post-treatment. She remains without evidence of recurrent disease, although longer follow-up is needed given the risk of late recurrence. Our case adds to the limited literature documenting the efficacy of adjuvant radiotherapy in melanotic schwannoma and is the first to describe the successful use of SRS for this rare disease.

Evaluating dosimetric parameters predictive of hematologic toxicity in cervical cancer patients undergoing definitive pelvic chemoradiotherapy.

PURPOSE: We performed a retrospective study of cervical cancer pelvic radiotherapy plans to explore dosimetric parameters predictive of hematologic toxicity (HT), with specific interest in evaluating metabolic parameters and identifying the best predictive model. METHODS: Active marrow was retroactively contoured as pelvic bone with SUV > mean on 18F-FDG-PET. "Highly active" marrow was contoured as the hottest 10-14% volume of active marrow. Pelvic bone contour was segmented into lumbosacral, iliac crest, and lower pelvis. Predictors of HT were evaluated using logistic regression and repeated measures modeling. RESULTS: One hundred women were evaluated from 2009 to 2020. The plurality/majority had stage IIIC1 disease (38%) and underwent IMRT (88%) with pelvic field alone (72%). The majority received weekly cisplatin (78%), and 82% completed at least five cycles. The most common HT was leukopenia (grade 2+: 68%). Predictors of grade 2+ and 3+ HT were baseline WBC (p < 0.001), and 10- and 20-Gy dosimetric parameters to the active marrow, highly active marrow, and pelvic bone. The best predictive model of leukocyte trajectory included baseline WBC (p < 0.001), highly active marrow V20 (p < 0.001), and interactions of baseline WBC with time (p < 0.001) and highly active marrow V20 (p < 0.001), such that those with low baseline WBC experienced the greatest impact of highly active marrow V20. CONCLUSION: Baseline WBC was highly predictive of HT; dosimetric predictors included dose to the active marrow, highly active marrow, and pelvic bone, with the greatest impact from V20 to the highly active marrow, particularly in women with low baseline WBC. Future studies should consider incorporating baseline WBC and limiting dose to the most highly active marrow.

Phase I/II Dose-Escalation Trial of 3-Fraction Stereotactic Radiosurgery for Resection Cavities From Large Brain Metastases: Health-related Quality of Life Outcomes.

OBJECTIVES: We investigated differences in quality of life (QoL) in patients enrolled on a phase I/II dose-escalation study of 3-fraction resection cavity stereotactic radiosurgery (SRS) for large brain metastases. METHODS: Eligible patients had 1 to 4 brain metastases, one of which was a resection cavity 4.2 to 33.5 cm3. European Organization for Research and Treatment of Cancer (EORTC) quality of life questionnaires core-30 (QLQ-30) and brain cancer specific module (QLQ-BN20) were obtained before SRS and at each follow-up. Nine scales were analyzed (global health status; physical, social, and emotional functioning; motor dysfunction, communication deficit, fatigue, insomnia, and future uncertainty). QoL was assessed with mixed effects models. Differences ≥10 points with q-value (adjusted P-value to account for multiplicity of testing) <0.10 were considered significant. RESULTS: Between 2009 and 2014, 50 enrolled patients completed 277 QoL questionnaires. Median questionnaire follow-up was 11.8 months. After SRS, insomnia demonstrated significant improvement (q=0.032, -17.7 points at 15 mo post-SRS), and future uncertainty demonstrated significant worsening (q=0.018, +9.9 points at 15 mo post-SRS). Following intracranial progression and salvage SRS, there were no significant QoL changes. The impact of salvage whole brain radiotherapy could not be assessed because of limited data (n=4 patients). In the 28% of patients that had adverse radiation effect, QoL had significant worsening in 3 metrics (physical functioning, q=0.024, emotional functioning q=0.001, and future uncertainty, q=0.004). CONCLUSIONS: For patients treated with 3-fraction SRS for large brain metastasis cavities, 8 of 9 QoL metrics were unchanged or improved after initial SRS. Intracranial tumor progression and salvage SRS did not impact QoL. Adverse radiation effect may be associated with at least short-term QoL impairments, but requires further investigation.

Stereotactic Radiotherapy for Recurrent Post-Transplant Primary Central Nervous System Lymphoma.

Post-transplant primary central nervous system lymphoma (PCNSL) is a rare complication of solid organ transplantation. The optimal therapy for post-transplant PCNSL is not well established and generally includes reduction of immunosuppression and chemotherapy. Progression after front-line chemotherapy is common, and whole-brain radiotherapy (WBRT) is a standard salvage treatment as there is a concern that localized treatment fields would not prevent out-of-field recurrences. However, WBRT is associated with neurotoxicity and morbidity in these patients with inherently poor prognoses. Here, we report a patient with local recurrence of post-transplant PCNSL who was treated with fractionated stereotactic radiotherapy (SRT). He had no clinical toxicity from treatment and maintained pre-treatment neurocognition and performance status. Local control was achieved for 20 months following SRT, at which point he developed an in-field recurrence. He restarted lymphoma therapy but died one month later from fungal pneumonia. For central nervous system (CNS) lymphoma, further data are needed to optimize tumor control and toxicity outcomes and identify patients in whom localized radiotherapy fields may be beneficial, avoiding the potential toxicity of WBRT.

#TrendingNow: Instagram Versus Twitter Activity Among Radiation Oncology Patients and Professionals.

PURPOSE: We aimed to evaluate recent Instagram and Twitter posts to identify the primary disseminators of information related to radiation therapy on social media (health care professionals vs patients), to characterize their influencer status, and to characterize the content of this information. METHODS AND MATERIALS: Using 2 commercial hashtag analytics platforms, 1000 of the most recent eligible posts from each platform were evaluated for content, tone, and engagement, as well as user (poster) characteristics. Inclusion criteria were as follows: unique posts, written in English, relevant to human cancer treatment, and containing 1 of 11 predetermined hashtags (#radiation, #radiotherapy, #radiationtherapy, #radiationoncology, #radonc, #radiationtherapist #radiationtreatment, #medphys, #cyberknife, #radiosurgery, #protontherapy). RESULTS: Users of radiation oncology content on Instagram were primarily patients/caregivers (47%), specifically adult patients (94%) with breast cancer (53%). Patient/caregiver content was focused on patient experience (79%), with approximately half specific to radiation therapy (51%), and most patient/caregiver posts demonstrated a positive tone (86%). In contrast, Twitter content was dominated by health care professionals (53%), specifically within radiation oncology (90% of unique users). Health care professional content was focused on colleague education/research dissemination (53%), with a high proportion of posts specific to radiation therapy (95%). CONCLUSIONS: Given the disproportionate number of patients versus radiation oncology professionals active on Instagram versus Twitter, and the lack of radiation therapy-specific content on Instagram, there may be an opportunity to improve patient outreach and education by promoting the presence of radiation oncologists on Instagram.

Technical report: 3D-printed patient-specific scalp shield for hair preservation in total skin electron beam therapy.

•Techniques for non-lead scalp-shielding in total skin therapy are lacking.•3D-printing is a promising technique for patient-specific conformal shielding.•We present a case of effective scalp shielding with 3D-printing.

Phase II trial evaluating efficacy of a Fitbit program for improving the health of endometrial cancer survivors.

BACKGROUND: Despite the favorable prognosis of early stage endometrial cancer, mortality from cardiovascular disease is high. We aimed to evaluate the efficacy of a Fitbit program to improve physical activity in endometrial cancer survivors. METHODS: Eligible patients were diagnosed with stage IA-IIIA endometrial adenocarcinoma, ≥3 months out from treatment. Participants received a Fitbit Alta and were randomized to receive communication via telephone or electronic methods (email/text). Communication was every two weeks for two months, then once during months four and five. Average daily steps were assessed weekly for nine months. RESULTS: The 46 analyzable patients demonstrated a baseline of 5641 median daily average steps. Average steps increased by 22% at 6 months but decreased to baseline by nine months. Baseline activity level (daily steps and walks per week) was the greatest predictor of activity level. Only the telephone intervention participants demonstrated increased activity level at several timepoints, although not maintained by nine months. BMI was unchanged. There was mild improvement in physical and social well-being in those with low baseline well-being (p = 0.009 and 0.014, respectively), regardless of intervention group. Emotional well-being correlated with step count (p = 0.005). CONCLUSIONS: Activity level was low and mildly improved on the Fitbit program with the telephone intervention, but effects did not persist by study completion. The program had the greatest impact on a select group of telephone intervention patients with high baseline walking frequency and low baseline step count. Others may require more intense intervention to promote more robust/persistent lifestyle changes.

Outcomes and Tolerability of Definitive and Preoperative Chemoradiation in Elderly Patients With Esophageal Cancer: A Retrospective Institutional Review.

PURPOSE: Our purpose was to report outcomes of elderly patients who underwent definitive treatment involving radiation therapy for esophageal cancer at our institution. METHODS AND MATERIALS: We performed a retrospective review of patients aged ≥75 years with esophageal cancer treated with definitive radiation therapy (≥45 Gy) at our institution from 1997 to 2019. Acute and late Radiation Therapy Oncology Group grade 3+ toxicities were recorded. Survival was estimated using the Kaplan-Meier method. RESULTS: Of the 89 patients included, median age was 80 and 78% were male. Median adjusted Charlson Comorbidity Index and Karnofsky Performance Status were 5 (3-12) and 80 (50-100), respectively. The majority of cancers were adenocarcinoma (58%), distal (67%), and stage III (62%). Fifty-eight percent underwent definitive chemoradiotherapy, and one-third underwent preoperative intent chemoradiotherapy. Median prescribed dose was 50 Gy (45-66 Gy), and intensity modulated radiation therapy was used in 76%. Eighty-five percent completed the radiation therapy course. Among these, 20% had radiation therapy breaks. For those receiving concurrent chemotherapy, 37% had a dose reduction and 39.5% had a break/cycle reduction. Acute grade 3+ toxicity was 22%, with 2% grade 5 toxicity. Twenty-one of the 29 patients (72%) treated with preoperative intent underwent surgery. There were no deaths 90 days postoperatively. For patients who underwent surgery, 1- and 2-year overall survival were 95% and 84%. For those who did not undergo surgery, 1- and 2-year overall survival were 70% and 52%. CONCLUSIONS: There is a role for aggressive radiation therapy in well-selected elderly patients with esophageal cancer. However, optimization of supportive care, chemotherapy regimens, radiation therapy dose/fractionation, and surgical indications are needed to reduce toxicity.

Telemedicine in Radiation Oncology: Is It Here to Stay? Impacts on Patient Care and Resident Education.

PURPOSE: Telemedicine was rapidly and ubiquitously adopted during the COVID-19 pandemic. However, there are growing discussions as to its role postpandemic. METHODS AND MATERIALS: We surveyed patients, radiation oncology (RO) attendings, and RO residents to assess their experience with telemedicine. Surveys addressed quality of patient care and utility of telemedicine for teaching and learning core competencies. Satisfaction was rated on a 6-point Likert-type scale. The quality of teaching and learning was graded on a 5-point Likert-type scale, with overall scores calculated by the average rating of each core competency required by the Accreditation Council for Graduate Medical Education (range, 1-5). RESULTS: Responses were collected from 56 patients, 12 RO attendings, and 13 RO residents. Patient feedback was collected at 17 new-patient, 22 on-treatment, and 17 follow-up video visits. Overall, 88% of patients were satisfied with virtual visits. A lower proportion of on-treatment patients rated their virtual visit as "very satisfactory" (68.2% vs 76.5% for new patients and 82.4% for follow-ups). Only 5.9% of the new patients and none of the follow-up patients were dissatisfied, and 27% of on-treatment patients were dissatisfied. The large majority of patients (88%) indicated that they would continue to use virtual visits as long as a physical examination was not needed. Overall scores for medical training were 4.1 out of 5 (range, 2.8-5.0) by RO residents and 3.2 (range, 2.0-4.0) by RO attendings. All residents and 92% of attendings indicated they would use telemedicine again; however, most indicated that telemedicine is best for follow-up visits. CONCLUSIONS: Telemedicine is a convenient means of delivering care to patients, with some limitations demonstrated for on-treatment patients. The majority of both patients and providers are interested in using telemedicine again, and it will likely continue to supplement patient care.

Mentorship in Radiation Oncology: Role of Gender Diversity in Abstract Presenting and Senior Author Dyads on Subsequent High-Impact Publications.

PURPOSE: To generate insights regarding the role of gender in research mentorship, we analyzed characteristics of abstracts selected for oral and poster discussion presentations at the American Society for Radiation Oncology annual meeting and subsequent high-impact publications. METHODS AND MATERIALS: Clinical radiation oncology abstracts selected for oral and poster discussion presentations at the American Society for Radiation Oncology annual meetings in 2014 and 2015 were reviewed. A multivariable logistic regression model evaluated factors associated with subsequent higher-impact publications among abstracts that led to manuscript publications. The primary independent variable was the presenting-senior (last) author gender dyad (divided into 4 groups based on gender of presenting and senior authors, respectively; eg, "MF" indicates male presenting and female senior). Dyads were classified as MF, FM, MM, or FF. RESULTS: Data were derived from 390 oral and 142 poster discussions. Presenting and senior author pairings were MM for 286 (53.8%), FF for 67 (12.6%), MF for 84 (15.8%), and FM for 94 (17.7%) abstracts. Overall, 403 abstracts led to subsequent publications, of which 52.1% (210) were in a higher-impact journal. Eventual publication in a higher-impact journal was significantly associated with senior author H-index (odds ratio [OR] 3.30 for H ≥ 41 vs < 17; group P = .007), grant support for the study (OR 2.09 for funded vs not, P = .0261), and with the presenting and senior author gender pairing (group P = .0107). Specifically, FM pairings (OR 2.48; 95% confidence interval, 1.32-4.66) and MF pairings (OR 2.38; 95% confidence interval, 1.19-4.77) had higher odds of high-impact publication than MM pairings, whereas there was no significant difference in this outcome between FF and MM pairings. CONCLUSIONS: Although unmeasured confounding remains possible, MF and FM dyads of presenting and senior authors were more likely than MM dyads to obtain journal publication in a higher-impact journal. Institutions and the profession should support the development and maintenance of respectful, collaborative cross-gender mentorship.

Successful use of frameless stereotactic radiosurgery for treatment of recurrent brain metastases in an 18-month-old child.

There are very few reported cases of stereotactic radiosurgery (SRS) delivered in children under 3 years of age. We report an 18-month-old boy with metastatic recurrence of undifferentiated round cell sarcoma to the brain which was treated with chemotherapy, resection and robotic frameless SRS. Frameless SRS was delivered without technical difficulties, acute adverse events, or clinical sequelae 1.5 months post-radiation. Longer term follow-up will be needed to evaluate local tumor control and effects on neurocognitive development, endocrine function and growth. This report adds to the literature of the few reported cases of successfully attempted SRS in very young children.

Quality at the American Society for Radiation Oncology Annual Meeting: Gender Balance Among Invited Speakers and Associations with Panel Success.

PURPOSE: The American Society for Radiation Oncology (ASTRO) annual meeting is the most prominent international conference in radiation oncology. It represents one of the greatest time efforts for ASTRO volunteers, and the quality of the annual meeting is a high priority. Measures of diversity have been linked with quality of academic efforts. We conducted a study of gender diversity of the ASTRO invited speakers, focusing on speaker and panel characteristics, and associations of these characteristics with measures of audience satisfaction. METHODS AND MATERIALS: We created a database of all invited speakers (n = 1499 cumulative speaking positions, n = 725 individual speakers) and panels (n = 381) in the ASTRO annual meetings from 2012 to 2016. Speaker characteristics were acquired using publically available online search tools (including Scopus for citation metrics). SAS software was used for statistical analysis. RESULTS: Of the 725 individual speakers, 27% were women. Men had higher median Hirsch index (H-index) (27 vs 20, P < .001), M-index (1.36 vs 1.11, P < .001), earlier first publication (1994 vs 1997), professorship (57% vs 40%, P < .001), chair status (25% vs 14%, P < .001) and fellow designations/distinctions (ie, FASTRO/FACR/FAAPM) (12% vs 9.5%, P < .17). Median panel gender distribution was 25% female, and greatest female representation was in breast, gynecology, and pediatrics. On multivariable analysis, panel characteristics associated with individual measures of audience satisfaction included single discipline presentations (metric: overall evaluation score), panels not proposed or endorsed by committee (metric: room count), higher H-index (metric: room count) and M-index (metric: request for session repeat), and panels with gender composition >50% female (metric: request for session repeat). Female conveners were associated with greater panel gender diversity. CONCLUSION: Given observations that women constitute a minority of invited speakers and that greater female representation correlates with a key panel success metric, efforts to ensure greater diversity of those included in AM speaking invitations merit serious attention.