Comprehensive clinical implementation, workflow, and FMEA of bespoke silicone bolus cast from 3D printed molds using open-source resources.

BACKGROUND: Bolus materials have been used for decades in radiotherapy. Most frequently, these materials are utilized to bring dose closer to the skin surface to cover superficial targets optimally. While cavity filling, such as nasal cavities, is desirable, traditional commercial bolus is lacking, requiring other solutions. Recently, investigators have worked on utilizing 3D printing technology, including commercially available solutions, which can overcome some challenges with traditional bolus. PURPOSE: To utilize failure modes and effects analysis (FMEA) to successfully implement a comprehensive 3D printed bolus solution to replace commercial bolus in our clinic using a series of open-source (or free) software products. METHODS: 3D printed molds for bespoke bolus were created by exporting the DICOM structures of the bolus designed in the treatment planning system and manipulated to create a multipart mold for 3D printing. A silicone (Ecoflex 00-30) mixture is poured into the mold and cured to form the bolus. Molds for sheet bolus of five thicknesses were also created. A comprehensive FMEA was performed to guide workflow adjustments and QA steps. RESULTS: The process map identified 39 and 30 distinct steps for the bespoke and flat sheet bolus workflows, respectively. The corresponding FMEA highlighted 119 and 86 failure modes, with 69 shared between the processes. Misunderstanding of plan intent was a potential cause for most of the highest-scoring failure modes, indicating that physics and dosimetry involvement early in the process is paramount. CONCLUSION: FMEA informed the design and implementation of QA steps to guarantee a safe and high-quality comprehensive implementation of silicone bolus from 3D printed molds. This approach allows for greater adaptability not afforded by traditional bolus, as well as potential dissemination to other clinics due to the open-source nature of the workflow.

Attitudes and Perception of the REFLECT Communication Curriculum for Clinical Oncology Graduate Medical Education.

Communication and interpersonal skills are essential components of oncology patient care. The REFLECT (Respect, Empathy, Facilitate Effective Communication, Listen, Elicit Information, Compassion, and Teach Others) curriculum is a novel framework to improve and refine physician/patient interactions for oncology graduate medical trainees. We seek to evaluate the attitudes and perceptions of the REFLECT communication curriculum among oncology trainees. Seven-question and 8-question Likert scale surveys (1 = not beneficial and 5 = beneficial) were distributed to resident/fellow participants and faculty mentors, respectively. Questions asked trainees and faculty about their perceptions of improvement in communication, handling of stressful situations, the value of the curriculum, and overall impression of the curriculum. Descriptive statistics determined the survey's baseline characteristics and response rates. Kruskal-Wallis rank sum tests were used to compare the distribution of continuous variables. Thirteen resident/fellow participants completed the participant survey. Six (43.6%) Radiation Oncology trainees and 7 (58.3%) Hematology/Oncology fellows completed the trainee survey. Eight (88.9%) Radiation Oncologists and 1 (11.1%) Medical Oncologist completed the observer survey. Faculty and trainees generally felt that the curriculum increased communication skills. Faculty responded more favorably to the program's impact on communication skills (median 5.0 vs. 4.0, p = 0.008). Faculty were more assertive about the curriculum's capabilities to improve a learner's ability to handle stressful situations (median 5.0 vs. 4.0, p = 0.003). Additionally, faculty had a more favorable overall impression of the REFLECT curriculum than the residents/fellows (median 5.0 vs. 4.0, p < 0.001). Radiation Oncology residents felt more strongly that the curriculum enhanced their ability to handle stressful topics, compared to Heme/Onc fellows (median 4.5 vs. 3.0, range 1-5, p = 0.379). Radiation Oncology trainees felt more consistently that the workshops improved their communication skills, compared to Heme/Onc fellows (median 4.5 vs. 3.5, range 1-5, p = 0.410). The overall impression between Rad Onc resident and Heme/Onc fellows was similar (median 4.0, p = 0.586). Conclusions: Overall, the REFLECT curriculum enhanced communication skills of trainees. Oncology trainees and faculty physicians feel that the curriculum was beneficial. As interactive skills and communication is critical to build positive interactions, further work is needed to improve the REFLECT curriculum.

Quantification of Potential Inequities in Breast Cancer Incidence in New Mexico Through Bayesian Disease Mapping.

INTRODUCTION: The incidence of breast cancer among non-Hispanic American Indian and Alaska Native (AI/AN) women varies across the United States. We applied county-level Bayesian disease mapping to quantify potential inequities in 10-year breast cancer incidence in New Mexico to better inform health equity initiatives among its non-Hispanic at-risk AI/AN population. METHODS: We used data from the Surveillance, Epidemiology, and End Results (SEER) program from 2005 through 2014 to identify new cases of breast cancer in New Mexico's 33 counties. To account for spatial variation, a county-level Area Deprivation Index, and the small area estimation problem inherent in these data, we borrowed strength globally and locally by applying Bayesian disease mapping to the counts of age-adjusted county-level breast cancer incidence. We quantified the disparity effect, as measured by the age-adjusted rate ratio, comparing the incidence of breast cancer between at-risk non-Hispanic AI/AN and non-Hispanic White women and assessed whether the ratio differed among counties. RESULTS: Accounting for over-dispersion and spatial correlation among the 33 counties and a county-level Area Deprivation Index, the posterior mean of the overall age-adjusted rate ratio was 0.384 (95% credible interval, 0.253--0.546). The age-adjusted rate of breast cancer in non-Hispanic AI/AN women was 0.38 times the corresponding age-adjusted rate for non-Hispanic White women; however, a significant reduction in breast cancer incidence was observed in 16 of the 33 counties. CONCLUSION: The application of Bayesian disease mapping to these data provided substantial evidence of an overall disparity in breast cancer incidence between at-risk non-Hispanic AI/AN and non-Hispanic White women in New Mexico, which was more marked than previously reported and limited to certain counties. Targeted statewide and county-level health-equity initiatives may lead to a reduction in these disparities.

Understanding American Indian Perceptions Toward Radiation Therapy.

Many American Indian (AI) and Alaska native (AN) patients do not complete guideline-concordant cancer care for the 4 most common cancers. Our aim was to better understand AI/AN attitudes toward radiation therapy (RT). Patients eligible for this survey study were AI/AN patients with cancer at the Phoenix Indian Medical Center who either received previous RT or were recommended to receive RT. An 18-item questionnaire was administered to each of the 50 participants from October 1, 2018, through February 15, 2019. Willingness to travel for RT was compared to respondent characteristics, concerns regarding RT, and obstacles to obtain RT. Duration of RT was important to 78% of patients: 24% would consider traveling 25 miles or more for a standard course, and 48% would travel that distance for a shorter course (P < .001). The top-ranked barriers to RT were transportation, cost of treatment, and insurance compatibility. The top-ranked concerns about RT were adverse effects, cost of treatment, and fear of RT. Concerns about adverse effects were associated with the radiation team's inability to explain the treatment (P = .05). Transportation concerns were significantly associated with accessibility (P = .02), communication with the RT team (P = .02), and fear of RT (P = .04). AI/AN patients are concerned about the adverse effects of RT and the logistics of treatment, particularly costs, transportation, and insurance compatibility. Use of culturally specific education and hypofractionation regimens may increase acceptance of RT for AI/AN patients with cancer, and this hypothesis will be tested in a future educational intervention-based study.

Electronic patient-reported outcomes and toxicities during radiotherapy for head-and-neck cancer.

PURPOSE: To characterize quality of life (QOL) using real-time, electronic patient-reported outcomes (ePROs) and to evaluate adverse events (AEs) and supportive care during head-and-neck radiotherapy (RT) and concurrent chemoradiotherapy (CCRT). METHODS: Sixty-five patients undergoing head-and-neck RT completed electronic, real-time, 12-item linear analog self-assessments (LASA) at baseline, before biweekly appointments, and at the last week of RT. Changes in QOL domains between time points were calculated. Clinical data were collected from the institutional medical record. AEs were recorded at the same time points as the LASA and graded. RESULTS: During head-and-neck RT, most patients had clinically meaningful decreases in all QOL domains except level of support, financial concerns, and legal concerns. QOL domains with the most prevalent, clinically meaningful decreases were fatigue (75.4% of patients; 95% CI, 62.9-84.9%), social activity (70.8%; 95% CI, 58.0-81.1%), and overall QOL (70.8%; 95% CI, 58.0-81.1%). All patients had grade 2 AEs; 35.4% had grade 3 (50.0%, CCRT; 12.0%, RT; P = .002). Weight loss averaged 5.5 kg (6.9 kg, CCRT; 2.8 kg, RT; P < .001). Intravenous hydration was needed in 52.3% (77.5%, CCRT; 12.0%, RT; P < .001); feeding tube placement 40.0% (57.5%, CCRT; 12.0%, RT; P = .001); emergency department visits without hospitalization, 10.8%; and emergent hospitalization, 27.7% (37.5%, CCRT; 12.0%, RT; P = .04). CONCLUSIONS: Head-and-neck RT, particularly CCRT, negatively impacts patients' overall QOL, social activity, and fatigue, with frequent grade 3 AEs, weight loss, intravenous hydration, feeding tube placement, ED visits, and hospitalization. Real-time ePROs allow providers to monitor QOL at multiple time points during RT, potentially allowing early intervention to improve QOL and mitigate AEs.

Exploratory study of the association of volumetric modulated arc therapy (VMAT) plan robustness with local failure in head and neck cancer.

This work is to show which is more relevant to cause local failures (LFs) due to patient setup uncertainty between the planning target volume (PTV) underdosage and the potential target underdosage subject to patient setup uncertainties in head and neck (H&N) cancer treated with volumetric-modulated arc therapy (VMAT). Thirteen LFs in 10 H&N patients treated by VMAT were analyzed. Measures have been taken to minimize the chances of insufficient target delineation for these patients and the patients were clinically determined to have LF based on the PET/CT scan results by an experienced radiologist and then reviewed by a second experienced radiation oncologist. Two methods were used to identify the possible locations of LF due to underdosage: (a) examining the standard VMAT plan, in which the underdosed volume in the nominal dose distribution (UVN) was generated by subtracting the volumes receiving the prescription doses from PTVs, and (b) plan robustness analysis, in which in addition to the nominal dose distribution, six perturbed dose distributions were created by translating the CT iso-center in three cardinal directions by the PTV margin. The coldest dose distribution was represented by the minimum of the seven doses in each voxel. The underdosed volume in the coldest dose distribution (UVC) was generated by subtracting the volumes receiving the prescription doses in the coldest dose distribution from the volumes receiving the prescription doses in the nominal dose distribution. UVN and UVC were subsequently examined for spatial association with the locations of LF. The association was tested using the binominal distribution and the Fisher's exact test of independence. We found that of 13 LFs, 11 were associated with UVCs (P = 0.011), while three were associated with UVNs (P = 0.99). We concluded that the possible target underdosage due to patient setup uncertainties appeared to be a more relevant factor associated with LF in VMAT for H&N cancer than the compromised PTV coverage at least for the patients included in this study.

Charged particle therapy versus photon therapy for paranasal sinus and nasal cavity malignant diseases: a systematic review and meta-analysis.

BACKGROUND: Malignant tumours arising within the nasal cavity and paranasal sinuses are rare and composed of several histological types, rendering controlled clinical trials to establish the best treatment impractical. We undertook a systematic review and meta-analysis to compare the clinical outcomes of patients treated with charged particle therapy with those of individuals receiving photon therapy. METHODS: We identified studies of nasal cavity and paranasal sinus tumours through searches of databases including Embase, Medline, Scopus, and the Cochrane Collaboration. We included treatment-naive cohorts (both primary and adjuvant radiation therapy) and those with recurrent disease. Primary outcomes of interest were overall survival, disease-free survival, and locoregional control, at 5 years and at longest follow-up. We used random-effect models to pool outcomes across studies and compared event rates of combined outcomes for charged particle therapy and photon therapy using an interaction test. FINDINGS: 43 cohorts from 41 non-comparative observational studies were included. Median follow-up for the charged particle therapy group was 38 months (range 5-73) and for the photon therapy group was 40 months (14-97). Pooled overall survival was significantly higher at 5 years for charged particle therapy than for photon therapy (relative risk 1·51, 95% CI 1·14-1·99; p=0·0038) and at longest follow-up (1·27, 1·01-1·59; p=0·037). At 5 years, disease-free survival was significantly higher for charged particle therapy than for photon therapy (1·93, 1·36-2·75, p=0·0003) but, at longest follow-up, this event rate did not differ between groups (1·51, 1·00-2·30; p=0·052). Locoregional control did not differ between treatment groups at 5 years (1·06, 0·68-1·67; p=0·79) but it was higher for charged particle therapy than for photon therapy at longest follow-up (1·18, 1·01-1·37; p=0·031). A subgroup analysis comparing proton beam therapy with intensity-modulated radiation therapy showed significantly higher disease-free survival at 5 years (relative risk 1·44, 95% CI 1·01-2·05; p=0·045) and locoregional control at longest follow-up (1·26, 1·05-1·51; p=0·011). INTERPRETATION: Compared with photon therapy, charged particle therapy could be associated with better outcomes for patients with malignant diseases of the nasal cavity and paranasal sinuses. Prospective studies emphasising collection of patient-reported and functional outcomes are strongly encouraged. FUNDING: Mayo Foundation for Medical Education and Research.

Relapse patterns after transoral laser microsurgery and postoperative irradiation for squamous cell carcinomas of the tonsil and tongue base.

OBJECTIVES: We evaluated relapse patterns after transoral laser microsurgery (TLM) in squamous cell carcinoma (SCC) of the tonsil and tongue base and evaluated the indications for adjuvant irradiation. METHODS: Between December 1, 1996, and December 31, 2005, 79 patients with previously untreated SCC of the tonsil or tongue base underwent TLM with or without neck dissection. Thirty-eight patients (48%) underwent postoperative irradiation (median, 62 Gy) to the primary site and the neck. Analysis of relapse patterns was performed on the basis of adverse risk factors and the presence or absence of adjuvant irradiation. RESULTS: The median follow-up for living patients was 47 months (range, 10 to 107 months), and patients were monitored for at least 2 years or until recurrence or death. Local, regional, and distant treatment failures numbered 4, 6, and 4 for surgery alone (n = 41) and 0, 2, and 6 for adjuvant irradiation (n = 38), respectively. Patients with high-risk features (extracapsular extension or at least 2 adverse factors) had locoregional control rates at 2 or more years of 66% and 94% for TLM alone and TLM plus adjuvant irradiation, respectively. CONCLUSIONS: Adjuvant irradiation after TLM resection of oropharyngeal SCC with intermediate- or high-risk features improves locoregional control compared with TLM alone.

Testing and Validation of a Custom Retrained Large Language Model for the Supportive Care of HN Patients with External Knowledge Base.

PURPOSE: This study aimed to develop a retrained large language model (LLM) tailored to the needs of HN cancer patients treated with radiotherapy, with emphasis on symptom management and survivorship care. METHODS: A comprehensive external database was curated for training ChatGPT-4, integrating expert-identified consensus guidelines on supportive care for HN patients and correspondences from physicians and nurses within our institution's electronic medical records for 90 HN patients. The performance of our model was evaluated using 20 patient post-treatment inquiries that were then assessed by three Board certified radiation oncologists (RadOncs). The rating of the model was assessed on a scale of 1 (strongly disagree) to 5 (strongly agree) based on accuracy, clarity of response, completeness s, and relevance. RESULTS: The average scores for the 20 tested questions were 4.25 for accuracy, 4.35 for clarity, 4.22 for completeness, and 4.32 for relevance, on a 5-point scale. Overall, 91.67% (220 out of 240) of assessments received scores of 3 or higher, and 83.33% (200 out of 240) received scores of 4 or higher. CONCLUSION: The custom-trained model demonstrates high accuracy in providing support to HN patients offering evidence-based information and guidance on their symptom management and survivorship care.

Implementation of the REFLECT Communication Curriculum for Clinical Oncology Graduate Medical Education.

Background: Communication and interpersonal skills are essential medical components of oncology patient care. Patients and families rely on physicians for treatment, expertise, guidance, hope, meaning, and compassion throughout a life-threatening illness. A provider's inability to empathize with patients is linked to physician-related fatigue and burnout. Because oncology training programs focus on teaching evidence-based medicine and clinical acumen, little time may be dedicated to professional development and acquisition of interactive skills. Traditional communication courses typically include two components: formal, knowledge-based learning skills, which are gained from didactic lectures, and role-playing, which usually occurs in small groups. We report the implementation of a novel longitudinal communication curriculum for trainees in Oncology. Materials and Methods: At a single-center institution, an innovative communication curriculum titled "REFLECT" (Respect, Empathy, Facilitate Effective Communication, Listen, Elicit Information, Compassion, and Teach Others) was implemented for radiation oncology residents and medical oncology fellows to improve and refine physician/patient interactions. All oncology specialty residents and fellows were eligible to participate in this communication curriculum. The curriculum emphasized a reflective process to guide trainees through challenging scenarios. Results: Since October 2018, this comprehensive course consisted of quarterly (four hour) workshops comprising assigned reading, knowledge assessments, didactic lectures, expert guest lecturers, standardized patient simulations, role-playing, patient/expert panels, coaching, reflective writing, and debriefing/feedback sessions. The curriculum provided longitudinal communication training integrated with the learners' daily physician/patient encounters rather than occasional isolated experiences. Fifteen workshops have been completed. Each focused on navigating challenging situations with patients, loved ones, or colleagues. Conclusions: Future directions of the curriculum will entail improving the communication skills of oncology trainees and gathering communication improvement data to assess the program's success formally.

Knowledge-based quality assurance of a comprehensive set of organ at risk contours for head and neck radiotherapy.

Introduction: Manual review of organ at risk (OAR) contours is crucial for creating safe radiotherapy plans but can be time-consuming and error prone. Statistical and deep learning models show the potential to automatically detect improper contours by identifying outliers using large sets of acceptable data (knowledge-based outlier detection) and may be able to assist human reviewers during review of OAR contours. Methods: This study developed an automated knowledge-based outlier detection method and assessed its ability to detect erroneous contours for all common head and neck (HN) OAR types used clinically at our institution. We utilized 490 accurate CT-based HN structure sets from unique patients, each with forty-two HN OAR contours when anatomically present. The structure sets were distributed as 80% for training, 10% for validation, and 10% for testing. In addition, 190 and 37 simulated contours containing errors were added to the validation and test sets, respectively. Single-contour features, including location, shape, orientation, volume, and CT number, were used to train three single-contour feature models (z-score, Mahalanobis distance [MD], and autoencoder [AE]). Additionally, a novel contour-to-contour relationship (CCR) model was trained using the minimum distance and volumetric overlap between pairs of OAR contours to quantify overlap and separation. Inferences from single-contour feature models were combined with the CCR model inferences and inferences evaluating the number of disconnected parts in a single contour and then compared. Results: In the test dataset, before combination with the CCR model, the area under the curve values were 0.922/0.939/0.939 for the z-score, MD, and AE models respectively for all contours. After combination with CCR model inferences, the z-score, MD, and AE had sensitivities of 0.838/0.892/0.865, specificities of 0.922/0.907/0.887, and balanced accuracies (BA) of 0.880/0.900/0.876 respectively. In the validation dataset, with similar overall performance and no signs of overfitting, model performance for individual OAR types was assessed. The combined AE model demonstrated minimum, median, and maximum BAs of 0.729, 0.908, and 0.980 across OAR types. Discussion: Our novel knowledge-based method combines models utilizing single-contour and CCR features to effectively detect erroneous OAR contours across a comprehensive set of 42 clinically used OAR types for HN radiotherapy.

Modelling small block aperture in an in-house developed GPU-accelerated Monte Carlo-based dose engine for pencil beam scanning proton therapy.

Purpose. To enhance an in-house graphic-processing-unit accelerated virtual particle (VP)-based Monte Carlo (MC) proton dose engine (VPMC) to model aperture blocks in both dose calculation and optimization for pencil beam scanning proton therapy (PBSPT)-based stereotactic radiosurgery (SRS).Methods and materials. A module to simulate VPs passing through patient-specific aperture blocks was developed and integrated in VPMC based on simulation results of realistic particles (primary protons and their secondaries). To validate the aperture block module, VPMC was first validated by an opensource MC code, MCsquare, in eight water phantom simulations with 3 cm thick brass apertures: four were with aperture openings of 1, 2, 3, and 4 cm without a range shifter, while the other four were with same aperture opening configurations with a range shifter of 45 mm water equivalent thickness. Then, VPMC was benchmarked with MCsquare and RayStation MC for 10 patients with small targets (average volume 8.4 c.c. with range of 0.4-43.3 c.c.). Finally, 3 typical patients were selected for robust optimization with aperture blocks using VPMC.Results. In the water phantoms, 3D gamma passing rate (2%/2 mm/10%) between VPMC and MCsquare was 99.71 ± 0.23%. In the patient geometries, 3D gamma passing rates (3%/2 mm/10%) between VPMC/MCsquare and RayStation MC were 97.79 ± 2.21%/97.78 ± 1.97%, respectively. Meanwhile, the calculation time was drastically decreased from 112.45 ± 114.08 s (MCsquare) to 8.20 ± 6.42 s (VPMC) with the same statistical uncertainties of ~0.5%. The robustly optimized plans met all the dose-volume-constraints (DVCs) for the targets and OARs per our institutional protocols. The mean calculation time for 13 influence matrices in robust optimization by VPMC was 41.6 s and the subsequent on-the-fly 'trial-and-error' optimization procedure took only 71.4 s on average for the selected three patients.Conclusion. VPMC has been successfully enhanced to model aperture blocks in dose calculation and optimization for the PBSPT-based SRS.

Elective Irradiation of Retropharyngeal Lymph Nodes as an Indication for Adjuvant Radiation Therapy After Transoral Surgery for Tonsil Cancer.

Treatment of squamous cell carcinoma of the tonsil involves primary radiation therapy (RT) or surgical resection. Historically, if RT was the primary or adjuvant treatment modality, most of the bilateral retropharyngeal lymph nodes (RPLNs) were treated electively with a therapeutic dose for subclinical disease, regardless of whether radiographically pathologic lymph nodes were seen on initial diagnostic imaging. De-escalation strategies include the incorporation of transoral surgery with the goal to either eliminate or reduce the dose of adjuvant RT or chemotherapy. Transoral surgery does not include elective removal of the RPLNs, and no guideline or outcome paper recommends adjuvant RT specifically to electively treat RPLNs. In this Topic Discussion, we discuss pertinent literature and suggest management decisions. The management decisions discussed in this Topic Discussion pertain to only tonsillar primaries and not those of the soft palate or base of the tongue.

Low contralateral failure rate with unilateral proton beam radiotherapy for oropharyngeal squamous cell carcinoma: A multi-institutional prospective study from the proton collaborative group.

INTRODUCTION: Unilateral radiation therapy is appropriate for select patients with oropharyngeal squamous cell carcinoma (OPSCC). The use of proton beam therapy (PBT) in the unilateral setting decreases the dose to the contralateral neck and organs at risk. This study aims to evaluate contralateral recurrences in patients who received ipsilateral PBT. METHODS: We evaluated the Proton Collaborative Group database for patients treated with PBT for head and neck squamous cell carcinoma between the years 2015-2020 at 12 institutions. Dosimetric analysis was performed in five cases. RESULTS: Our analysis included 41 patients that received ipsilateral PBT with a mean follow-up of 14.7 months. 37% patients (n = 15) were treated for recurrent disease, and 63% (n = 26) were treated for de novo disease. Oropharyngeal sites included tonsillar fossa (n = 30) and base of tongue (n = 11). The median dose and BED delivered were 69.96 CGE and 84 Gy, respectively. Eight (20%) patients experienced at least one grade 3 dysphagia (n = 4) or esophagitis (n = 4) toxicity. No grade ≥ 4 toxicities were reported. There was one (2.4%) failure in the contralateral neck. The 1-year locoregional control was 88.9% and the freedom from distant metastasis was 95.5% (n = 2). The dosimetric analysis demonstrated similar ipsilateral level II cervical nodal region doses, whereas contralateral doses were higher with photon plans, mean: 15.5 Gy and 0.7CGE, D5%: 25.1 Gy and 6.6CGE. CONCLUSIONS: Our series is the first to report outcomes for patients with OPSCC receiving unilateral PBT. The contralateral neck failure rate was excellent and comparable to failure rates with photon irradiation.

Mean Oral Cavity Organ-at-Risk Dose Predicts Opioid Use and Hospitalization during Radiotherapy for Patients with Head and Neck Tumors.

BACKGROUND: Approximately 75% of all head and neck cancer patients are treated with radiotherapy (RT). RT to the oral cavity results in acute and late adverse events which can be severe and detrimental to a patient's quality of life and function. The purpose of this study was to explore associations between RT dose to a defined oral cavity organ-at-risk (OAR) avoidance structure, provider- and patient-reported outcomes (PROs), opioid use, and hospitalization. METHODS: This was a retrospective analysis of prospectively obtained outcomes using multivariable modeling. The study included 196 patients treated with RT involving the oral cavity for a head and neck tumor. A defined oral cavity OAR avoidance structure was used in all patients for RT treatment planning. Validated PROs were collected prospectively. Opioid use and hospitalization were abstracted electronically from medical records. RESULTS: Multivariable modeling revealed the mean dose to the oral cavity OAR was significantly associated with opioid use (p = 0.0082) and hospitalization (p = 0.0356) during and within 30 days of completing RT. CONCLUSIONS: The findings of this study may be valuable in RT treatment planning for patients with tumors of the head and neck region to reduce the need for opioid use and hospitalization during treatment.

Dose Deintensified 3-Day Photon, Proton, or Brachytherapy: A Nonrandomized Controlled Partial Breast Irradiation Trial.

PURPOSE: The optimal approach for partial breast irradiation (PBI) is unknown. We investigated a novel de-intensified 3-fraction PBI regimen for photons, protons, and brachytherapy. METHODS AND MATERIALS: A multicenter nonrandomized controlled trial with the primary outcome of adverse cosmesis at 3 years versus before PBI. Eligibility criteria were age ≥50 years treated with breast-conserving surgery for node-negative estrogen receptor-positive (ER+) invasive breast cancer or any ductal carcinoma in situ (DCIS) measuring ≤2.5 cm. Photon and proton PBI were prescribed 21.9 Gy (relative biological effectiveness) and brachytherapy 21 Gy in 3 fractions. Radiation therapy technique and adjuvant endocrine therapy were selected at physician and patient discretion. RESULTS: Between June 17, 2015, and July 13, 2017, 161 eligible patients were treated with photons (56), protons (49), or brachytherapy (56). Median patient age was 66.8 years. One hundred twenty-six (78.3%) had invasive breast cancer (all ER+) and 35 (21.7%) had DCIS (88.6% ER+). Fifty-four percent of patients with invasive breast cancer and 25.8% of patients with ER+ DCIS initiated and adhered to the prescribed endocrine therapy. The proportion of patients with adverse cosmesis (by trained nurse assessment) was 14.5% at baseline and 2.3% at 3 years (difference, -12.2%; 95% CI, -100% to -6.4%). Adverse cosmesis at the last follow-up, with a median follow-up of 5 years, was 5.7% by nurse assessment, 5.6% by panel assessment of digital photographs, and 5.2% by patient self-report. There were no observed clinically meaningful changes in other patient-reported outcomes, and just 2 grade 2 or higher adverse events, both grade 2, in the brachytherapy cohort. Five-year local recurrence-free survival and progression-free survival were 98.0% and 95.5%, respectively. There were no local recurrences among 60 patients with invasive breast cancer and Ki67 ≤13.25%. CONCLUSIONS: Deintensified 3-day PBI provided favorable disease control, tolerability, and cosmetic outcomes, meeting the prespecified criteria for acceptability. This approach is an attractive option for patients with small node-negative ER+ breast cancer and DCIS.

Modelling small block aperture in an in-house developed GPU-accelerated Monte Carlo-based dose engine for pencil beam scanning proton therapy.

Purpose: To enhance an in-house graphic-processing-unit (GPU) accelerated virtual particle (VP)-based Monte Carlo (MC) proton dose engine (VPMC) to model aperture blocks in both dose calculation and optimization for pencil beam scanning proton therapy (PBSPT)-based stereotactic radiosurgery (SRS). Methods and Materials: A module to simulate VPs passing through patient-specific aperture blocks was developed and integrated in VPMC based on simulation results of realistic particles (primary protons and their secondaries). To validate the aperture block module, VPMC was first validated by an opensource MC code, MCsquare, in eight water phantom simulations with 3cm thick brass apertures: four were with aperture openings of 1, 2, 3, and 4cm without a range shifter, while the other four were with same aperture opening configurations with a range shifter of 45mm water equivalent thickness. Then, VPMC was benchmarked with MCsquare and RayStation MC for 10 patients with small targets (average volume 8.4 cc with range of 0.4 - 43.3 cc). Finally, 3 typical patients were selected for robust optimization with aperture blocks using VPMC. Results: In the water phantoms, 3D gamma passing rate (2%/2mm/10%) between VPMC and MCsquare was 99.71±0.23%. In the patient geometries, 3D gamma passing rates (3%/2mm/10%) between VPMC/MCsquare and RayStation MC were 97.79±2.21%/97.78±1.97%, respectively. Meanwhile, the calculation time was drastically decreased from 112.45±114.08 seconds (MCsquare) to 8.20±6.42 seconds (VPMC) with the same statistical uncertainties of ~0.5%. The robustly optimized plans met all the dose-volume-constraints (DVCs) for the targets and OARs per our institutional protocols. The mean calculation time for 13 influence matrices in robust optimization by VPMC was 41.6 seconds and the subsequent on-the-fly "trial-and-error" optimization procedure took only 71.4 seconds on average for the selected three patients. Conclusion: VPMC has been successfully enhanced to model aperture blocks in dose calculation and optimization for the PBSPT-based SRS.

Adenoid cystic carcinoma of the head and neck: Patterns of recurrence and implications for intensity-modulated radiotherapy.

BACKGROUND: We seek to inform radiotherapy (RT) delivery for adenoid cystic carcinoma of the head and neck (ACC) by evaluating RT techniques and recurrence patterns. METHODS: We identified patients with ACC treated with curative-intent RT from 2005 to 2021. Imaging was reviewed to determine local recurrence (LR). RESULTS: Ninety-one patients were included. The 5-year LR risk was 12.2% (6.6-22.7). One patient each experienced a marginal and out-of-field recurrence. Patients receiving >60 Gy postoperatively had a 5-year LR risk of 0% compared to 10.7% (4.2-27.2) with ≤60 Gy. Those receiving 70 and <70 Gy definitively had a 5-year LR risk of 15.2% (2.5-91.6) and 33.3% (6.7-100.0), respectively. No patients had regional nodal failure. CONCLUSIONS: Modern, conformal RT for ACC results in low rates of LR. Doses >60 and 70 Gy may improve control in the postoperative and definitive settings, respectively. Elective nodal treatment can be omitted in well-selected patients.

Clinicopathologic Factors and Their Association with Outcomes of Salivary Duct Carcinoma: A Multicenter Experience.

Purpose: This series reports long-term clinical outcomes of patients with salivary duct carcinoma (SDC), which is associated with a poor prognosis. Methods and Materials: Eighty-nine patients with SDC were treated with curative intent from February 5, 1971, through September 15, 2018. Kaplan-Meier and competing risk analyses were used to estimate locoregional control, distant metastasis-free survival (DMFS), progression-free survival, and overall survival (OS). Cox regression analyses of disease and treatment characteristics were performed to discover predictors of locoregional control, DMFS, and OS. Results: Median follow-up was 44.1 months (range, 0.23-356.67). The median age at diagnosis was 66 years (interquartile range, 57-75). Curative surgery followed by adjuvant radiation therapy was performed in 73 patients (82%). Chemotherapy was delivered in 26 patients (29.2%). The 5-year local recurrence and distant metastasis rates were 27% and 44%, respectively, with death as a competing risk. Distant metastasis was associated with lymph node-positive disease (hazard ratio [HR], 3.16; 95% confidence interval [CI], 1.38-7.23; P = .006), stage IV disease (HR, 4.78; 95% CI, 1.14-20.11; P = .033), perineural invasion (HR, 4.56; 95% CI, 1.74-11.97; P = .002), and positive margins (HR, 9.06; 95% CI, 3.88-21.14; P < .001). Median OS was 4.84 years (95% CI, 3.54-7.02). The 5-year OS was 42%. Reduced OS was associated with lymphovascular space invasion (HR, 3.49; 95% CI, 1.2-10.1; P = .022), perineural invasion (HR, 2.05; 95% CI, 1.06-3.97; P = .033), positive margins (HR, 2.7; 95% CI, 1.3-5.6; P = .011), N2 disease (HR, 1.88; 95% CI, 1.03-3.43; P = .04), and N3 disease (HR, 11.76; 95% CI, 3.19-43.3; P < .001). Conclusions: In this single-institution, multicenter retrospective study, the 5-year survival was 42% in patients with SDC. Lymphovascular space invasion, lymph node involvement, and higher staging at diagnosis were associated with lower DMFS and OS.