Faculty Bibliography

Purpose: Multi-isocentric treatment delivery for CSI and TBI poses specific challenges for treatment delivery. We have developed a software tool to streamline all aspects of delivery for therapists and physicists at the machine, as well as to inform attending physicians of setup variability and image residuals at different locations.
Method(s): Our institution delivers VMAT-based CSI and TBI with up to 3 and 7 isocenters, respectively. A software tool was developed to assist with treatment delivery including initial patient setup, patient imaging, automatic calculation of the optimal global shift based on each isocenter's ideal shift, and automatic calculation of each isocenter's couch coordinates. Initial treatment couch coordinates are queried via the Eclipse scripting API. The global shift was calculated prioritizing the head isocenter for CSI treatments and the chest isocenter for TBI treatments by first maximizing residual tolerance at any other location prior to accepting any residual deviation at these locations. Maximum residuals tolerance was determined based on target margins, plan uncertainty and as per physician instructions. Delivery parameters are reported to a document uploaded to ARIA via API.
Result(s): The developed tool was employed for 11 cases. The software tool replaced the need for plan shift comments or instructions for therapists. In particular, its use eliminated the need to provide isocenter shifts to therapists by directly providing final couch parameters for treatment, greatly reducing the risk of delivery errors. The software effectively informed the therapists if any expected tolerance was surpassed, triggering a patient setup evaluation.
Conclusion(s): The described software tool is a core component to our multi-isocenter treatment programs and has streamlined delivery of these complex techniques that would otherwise require complicated instructions, including multiple shifts and on-the-fly calculations of optimal image alignment based on multiple imaging locations. This has substantially reduced the possibility of delivery errors

Purpose: In-vivo dosimetry for conventional total body irradiation (TBI) utilize point detectors placed along the patient surface to confirm the delivered dose matches prescription dose. However, in the volumetrically modulated arc therapy (VMAT) approach to TBI, the electronic portal imager device (EPID) can be utilized to acquire a 2-dimensional transmission fluence plane. This work explores the relationship between patient setup accuracy with transit in-vivo dosimetry.
Method(s): A total of 192 fields were investigated. Each VMAT plan consisted of four isocenters: head, chest, abdomen, and pelvis. Prior to treatment, the patient was imaged at the head, pelvis, and chest. Optimal couch shifts were determined for each isocenter under image guidance. The optimal IGRT shifts were determined using an inhouse application that minimized dose deviation using criteria established through plan uncertainty analysis performed in Eclipse. Translational couch residuals were recorded and defined as the difference in the global shift calculated and the optimal couch position with shifts. Transit dosimetry was measured per arc, and analyzed using SNC PerFRACTION with a gamma criteria of 10%/5mm, 5%/5mm, and 5%/7mm.
Result(s): Based on plan uncertainty analysis, clinical threshold for couch residuals were set to 7 mm (5 mm for chest isocenter) as there would be minimal impact on target coverage and organ sparing at those levels. Transit dosimetry showed that the average pass rate across all fields was 99.6%, 97.0%, and 99.2% for 10%/5mm, 5%/5mm, and 5%/7mm gamma criteria, respectively. Pearson correlation tests showed that there was weak correlation between gamma criteria and couch residuals. At stringent 3%/5mm gamma criteria, moderate correlation was found between lateral couch residuals for the head and chest and the head and chest arc analysis.
Conclusion(s): Transit dosimetry showed high pass rates using our couch residual tolerances, which confirmed the plan uncertainty analysis performed during treatment planning

Purpose/UNASSIGNED:Resident physicians use social media (SM) for many reasons. We sought to characterize current SM use by radiation oncology (RO) trainees for education and professional development. Methods and Materials/UNASSIGNED:An anonymous 40-question survey was sent by e-mail to RO residents in the 2018 to 2019 academic year. SM platform use, time spent on SM, professional use, and opinions regarding SM use were assessed. Descriptive statistics and a univariate logistic regression analysis were performed to identify factors associated with perceptions of SM and spending >25% of SM time for academic or professional purposes. Results/UNASSIGNED:< .001) were more likely to spend >25% of their SM time on professional/academic purposes. The vast majority of respondents agreed that SM exposed them to novel educational content (82%) and was helpful for career development (65%). In addition, 69% agreed that SM can improve clinical skills and knowledge. A substantial minority agreed that SM distracts them from studying (38%) or they felt pressure to have a SM presence (29%). Conclusions/UNASSIGNED:Most RO residents reported that SM provides novel educational content and can help with career development. Potential disadvantages of SM for trainees may include distraction and pressure to maintain a SM presence. SM use by RO trainees merits further research to optimize its potential for education and professional development.

BACKGROUND:Young women with ductal carcinoma in situ (DCIS) represent a unique cohort given considerations for future risk reduction and treatment effects on fertility and quality of life. We evaluated national patterns of care in the treatment of young women and the impact of those treatments on overall survival (OS). METHODS:Women younger than 50 years of age diagnosed with pure DCIS from 2004 to 2016 in the National Cancer Database (NCDB) were identified. Clinical, demographic, and choice of local therapy are summarized and trended over time. OS was analyzed using Cox proportional hazard models. RESULTS:A total of 52,150 women were identified, and the most common surgical treatment was breast-conservation surgery (BCS; 59%). Bilateral mastectomy (BM) increased in frequency from 2004 to 2016 (11-27%; p < 0.001). In women < 40 years of age, BM (39%) surpassed BCS (35%) in 2010 with a continued upward trend. On multivariable analysis, no OS benefit of BM (hazard ratio [HR] 0.99, p = 0.90) or unilateral mastectomy (UM; HR 0.98, p = 0.80) was observed when compared with BCS + radiation therapy (RT). Inferior OS was seen with BCS, Black race, estrogen receptor (ER)-negative, and tumor ≥ 2.5 cm (p ≤ 0.006). In ER+ patients, there was a significant difference in endocrine therapy (ET) use between BM (11%), UM (33%), and BCS (28%) compared with BCS + RT (64%, p < 0.001). CONCLUSION/CONCLUSIONS:The use of BM for DCIS is increasing in younger patients and now exceeds breast-conservation approaches in women < 40 years of age with no evidence of improved OS. Among ER+ patients, the rates of ET are lower in the BM, UM, and BCS-alone groups compared with BCS + RT.

BACKGROUND:) that evaluates recurrence risk has been developed and validated. We evaluated the impact of DCISionRT on clinicians' recommendations for adjuvant RT. METHODS:The PREDICT study is a prospective, multi-institutional, observational registry in which patients underwent DCISionRT testing. The primary endpoint was to identify the percentage of patients where testing led to a change in RT recommendations. RESULTS:Overall, 539 women were included in this study. Pre DCISionRT testing, RT was recommended to 69% of patients; however, post-testing, a change in the RT recommendation was made for 42% of patients compared with the pre-testing recommendation; the percentage of women who were recommended RT decreased by 20%. For women initially recommended not to receive an RT pre-test, 35% had their recommendation changed to add RT following testing, while post-test, 46% of patients had their recommendation changed to omit RT after an initial recommendation for RT. When considered in conjunction with other clinicopathologic factors, the elevated DCISionRT score risk group (DS > 3) had the strongest association with an RT recommendation (odds ratio 43.4) compared with age, grade, size, margin status, and other factors. CONCLUSIONS:DCISionRT provided information that significantly changed the recommendations to add or omit RT. Compared with traditional clinicopathologic features used to determine recommendations for or against RT, the factor most strongly associated with RT recommendations was the DCISionRT result, with other factors of importance being patient preference, tumor size, and grade.

We describe a model case of unplanned pregnancy during radiation therapy to the chest wall and peripheral lymphatics for breast cancer. We use the Morbidity and Mortality Conference format to demonstrate how radiation oncology departments should evaluate and manage this situation.

PURPOSE/OBJECTIVE:Anti-HER2 therapy delivered in the adjuvant setting for breast cancer is given in conjunction with cytotoxic chemotherapy. For HER2-positive (HER2+) patients who cannot tolerate chemotherapy, there is no randomized data regarding the role of anti-HER2 therapy without chemotherapy. METHODS:The National Cancer Database (NCDB) was queried for non-metastatic breast cancer patients with estrogen receptor-positive (ER+) and HER2+ breast cancer who received surgery and endocrine therapy, without chemotherapy from 2013 to 2016. Outcomes were compared between endocrine therapy alone (ET) or endocrine therapy with anti-HER2 therapy (ET + aHER2). Univariate and multivariate Cox-proportional hazards models were used to analyze the association between clinical characteristics and survival outcomes between groups. Propensity score matching (PSM) was performed to account for differences between the two groups. RESULTS:Of all patients with non-metastatic ER+/HER2+ breast cancer, we identified 9458 (20.5%) who did not receive chemotherapy. Of the 6741 patients who received ET, 17.2% also received aHER2 therapy. Median follow-up was 31.7 months (IQR 21.1-42.1). In the aHER2 group (vs. ET), there were more patients with older age, higher stage, node positivity, poorly or undifferentiated disease, lymphovascular invasion, lobular cancer, and Medicare insurance. Compared to the ET cohort, ET + aHER2 was not significantly associated with improved OS on multivariate analysis (HR 0.88 95% CI 0.68-1.15) or after propensity score matching (HR 0.80 95% CI 0.57-1.11). CONCLUSIONS:There is no significant difference in survival with the addition of HER2 therapy to endocrine therapy in ER+/HER2+ non-metastatic breast cancer patients who do not receive chemotherapy. To our knowledge, this is the largest series investigating this question.

The purpose of this work is to establish an automated approach for a multiple isocenter volumetric arc therapy (VMAT)-based TBI treatment planning approach. Five anonymized full-body CT imaging sets were used. A script was developed to automate and standardize the treatment planning process using the Varian Eclipse v15.6 Scripting API. The script generates two treatment plans: a head-first VMAT-based plan for upper body coverage using four isocenters and a total of eight full arcs; and a feet-first AP/PA plan with three isocenters that covers the lower extremities of the patient. PTV was the entire body cropped 5 mm from the patient surface and extended 3 mm into the lungs and kidneys. Two plans were generated for each case: one to a total dose of 1200 cGy in 8 fractions and a second one to a total dose of 1320 cGy in 8 fractions. Plans were calculated using the AAA algorithm and 6 MV photon energy. One plan was created and delivered to an anthropomorphic phantom containing 12 OSLDs for in-vivo dose verification. For the plans prescribed to 1200 cGy total dose the following dosimetric results were achieved: median PTV V100% = 94.5%; median PTV D98% = 89.9%; median lungs Dmean = 763 cGy; median left kidney Dmean = 1058 cGy; and median right kidney Dmean = 1051 cGy. For the plans prescribed to 1320 cGy total dose the following dosimetric results were achieved: median PTV V100% = 95.0%; median PTV D98% = 88.7%; median lungs Dmean = 798 cGy; median left kidney Dmean = 1059 cGy; and median right kidney Dmean = 1064 cGy. Maximum dose objective was met for all cases. The dose deviation between the treatment planning dose and the dose measured by the OSLDs was within ±4%. In summary, we have demonstrated that scripting can produce high-quality plans based on predefined dose objectives and can decrease planning time by automatic target and optimization contours generation, plan creation, field and isocenter placement, and optimization objectives setup.

PURPOSE/OBJECTIVE:Autoimmune connective tissue disease (CTD) has historically represented a relative contraindication to breast conservation (BC) among patients with early stage breast cancer. Controversy exists regarding hypofractionated radiotherapy (RT) among patients with CTDs. We evaluated acute and late toxicity in patients with breast cancer and CTD treated with BC. METHODS AND MATERIALS/METHODS:Of 1983 patients treated with BC from 2012 to 2016, we identified 91 patients with autoimmune disease (AD). Each patient was matched to a control without AD based on age, RT field and fractionation. RT toxicity and clinician-rated cosmesis were compared between cases and controls. Overall survival, disease-free survival, and local recurrence free survival were estimated using the Kaplan-Meier method. RESULTS:Median follow-up was 49.9 months for cases and 53.0 months for controls. 67% of cases and controls were treated with hypofractionated RT. There was no difference in grade 2/3 acute toxicity between cases and controls (26.4% vs. 16.5%, p=0.148, respectively). There was a significantly higher rate of grade 2/3 late toxicity among cases (25.8% vs 12.1%, p=0.049). Active AD at the time of RT increased the rate of grade 2/3 late toxicity compared to controls (41.7% vs. 11.4%, p=0.018). Among patients treated with hypofractionated RT, there was no difference in acute or late grade 2/3 toxicity between cases and controls (acute: 13.1% cases vs. 11.5% controls, p=1; late: 11.9% in cases vs 13.1% in controls, p=1). Rate of good/excellent clinician- rated cosmesis was similar between groups (92.9% vs 98.9%, p=0.142). CONCLUSIONS:In the largest matched case control study of patients with CTD treated with conventional and hypofractionated RT, we demonstrate low rates of radiation toxicity, with good to excellent clinician-rated cosmesis. There was increased late toxicity in cases, especially in patients with active AD at time of RT. There was no increase in acute or late toxicity in the patients treated with hypofractionation.