Faculty Bibliography

AIMS/OBJECTIVE:Our institution regularly offers accelerated partial breast irradiation (APBI) of 3000 cGy in 5 fractions. This study compares dosimetry and acute toxicities between patients treated in the prone and supine positions. MATERIALS AND METHODS/METHODS:We retrospectively reviewed all patients with in-situ or invasive breast cancer treated with 3000 cGy in 5 fractions of APBI at our institution between January 2022 and December 2023. We obtained dosimetric and acute toxicity data for each patient. Differences between treatment groups were analyzed using the Wilcoxon rank-sum, Pearson's Chi-squared and Fisher's exact tests. RESULTS:A total of 168 patients were identified, with 134 (79.8%) treated prone and 34 (20.2%) treated supine. Of the supine patients, 23 (67.6%) were treated with photon-only plans and 11 (32.4%) with mixed photon-electron plans. There were no statistically significant differences in age, body mass index (BMI), tumor size, or breast laterality between the two groups. Planning target volume (PTV) volume was larger for prone patients (P = 0.002). Target coverage was excellent and similar in both positions. Ipsilateral breast dosimetry did not differ significantly between groups. Median mean heart dose (MHD) was significantly lower in prone patients (9.6 cGy vs 14.9 cGy, P = 0.033). This difference was more pronounced in right-sided patients than in left-sided patients (right: 6.9 cGy prone vs 8.6 cGy supine, P = 0.037; left: 17.6 cGy prone vs 16.5 cGy supine, P = 0.710). MHD was also significantly higher in mixed photon-electron plans (22.5 cGy) than in supine photon-only plans (10.6 cGy) P = 0.009. Mean ipsilateral lung V10 Gy was lower for prone patients (0.28% vs 1.44%, P =< 0.001). Grade 1-2 dermatitis was more frequent in the supine cohort (P = 0.029). Fatigue was significantly higher in patients with BMI ≥30 vs patients with BMI <30 (P = 0.035). CONCLUSION/CONCLUSIONS:Both treatment positions were safe, and there were no differences in target coverage or ipsilateral breast dosimetry between the two groups. Prone positioning was associated with lower heart and lung doses as well as lower rates of acute dermatitis, but heart and lung doses were minimal regardless of treatment position.

BACKGROUND:Whole-breast ultra-hypofractionated radiation therapy is an accepted adjuvant option for early-stage breast cancer, but evidence remains limited for patients with systemic lupus erythematosus (SLE), particularly those receiving chronic disease modifying antirheumatic drug (DMARD) therapy. CLINICAL SCENARIO/METHODS:A 76-year-old woman with clinically quiescent SLE/Sjögren syndrome on mycophenolate mofetil was diagnosed with left breast invasive ductal carcinoma, ER/PR-positive and HER2-negative. After breast-conserving surgery and sentinel lymph node biopsy, pathology showed a 13-mm grade 3 tumor with lymphovascular invasion, negative margins, and 0/5 sentinel nodes, pT1cN0(sn), stage IA. Radiation omission was considered because of age, node-negative disease, and planned endocrine therapy; however, grade 3 histology, lymphovascular invasion, and Ki-67 of 43% placed her outside the lowest-risk populations supporting omission. During a period of active regional conflict with daily missile threats, an expedited regimen was selected. She received 26 Gy in 5 fractions to the left whole breast using supine field in-field 3-dimensional conformal radiation therapy, without regional nodal irradiation or tumor-bed boost. Dosimetry was acceptable, with PTV V95% 95%, maximum dose 104.9%, mean heart dose 0.8 Gy, and ipsilateral lung V8 Gy 15%. OUTCOME/RESULTS:Approximately 2 weeks after treatment, she developed progressive erythema, diffuse breast edema, pain, and extensive confluent moist desquamation beyond skin folds, without evidence of infection, consistent with RTOG grade 3 acute radiation dermatitis. Management included topical corticosteroids, silver sulfadiazine, enzyme alginogel, polymeric membrane dressings, analgesics, close nursing follow-up, and subsequent lymphedema-directed physiotherapy. Recovery was prolonged, and later rheumatologic reassessment documented recurrent systemic symptoms requiring belimumab. CONCLUSION/CONCLUSIONS:Although causality cannot be proven, the severity of acute dermatitis was atypical for FAST-Forward whole-breast irradiation and suggests that SLE-associated radiosensitivity may have contributed. Modern data indicate that connective tissue disease is not an absolute contraindication to breast radiation, and hypofractionation can be feasible. However, evidence is sparse for whole-breast ultra-hypofractionation in patients with SLE on chronic DMARD therapy. Multidisciplinary assessment, explicit counseling, consideration of moderate hypofractionation or reduced-volume treatment when oncologically acceptable, and systematic reporting of severe toxicity are warranted.

PURPOSE/OBJECTIVE:Peer review is an integral process in the field of radiation oncology to ensure that radiation plans meet appropriate clinical and dosimetric standards. We report a pilot quality assessment of our peer review process and a model for utilizing the results of this pilot project for resident education. METHODS:This study prospectively tracked peer review in our department over the course of 9 months and tracked all plans that were not approved. Reasons for lack of approval were recorded. Plans that did not pass peer review were anonymized and imported to a shared folder for future educational use. Eight cases were used in a mock peer review didactics session with the residents. The session was led by two residents, a dosimetrist, and attending physician while the remaining residents were tasked with finding the error or reason for lack of approval. Pre-and post-session surveys were conducted to evaluate the value of the session. RESULTS:Out of 2,209 total cases presented during peer review, 37 treatment plans (2%) were not approved. The most common reasons for disapproval included contours (24%), dose (22%), and workflow (22%). Breast and skin cases had the highest numbers of not approved plans, 19% and 16% respectively. Relative to the total number of cases presented for each disease site, skin had the highest rate of disapproval at 5.4% followed by gynecologic treatments at 4.3%. All residents found the mock peer review didactics session to be "helpful" or "very helpful" on the post-session survey and would want additional sessions in the future. CONCLUSION/CONCLUSIONS:Overall, our study showed a low rate of disapproval during peer review, and our resident survey results indicated that a mock peer review didactics session would be a valuable addition to training.

PURPOSE/OBJECTIVE:The recently published results of the National Surgical Adjuvant Breast and Bowel Project B51 trial suggest that regional nodal irradiation may be safely omitted in patients with cT1-3N1 breast cancer treated with either lumpectomy or mastectomy, and achieve a pathologic complete response (pCR) in the regional nodes. Of note, almost 80% of patients on the trial demonstrated breast pCR. The goal of our study was to compare clinical outcomes between patients with breast pCR versus not. METHODS AND MATERIALS/METHODS:We included all patients treated at a single institution between 2010 and 2021 with cT1-3N1 breast cancer (pathologically proven via fine needle aspiration) who completed neoadjuvant chemotherapy and had axillary nodal pCR. Patients could undergo breast-conserving surgery or mastectomy. Univariate and multivariate logistic models were used to identify factors associated with breast pCR. Cox proportional hazard model was used to find independent prognostic variables associated with disease-free survival (DFS). RESULTS:We identified 124 patients meeting eligibility criteria. Of those, 72 patients (58%) achieved a breast pCR. On multivariate analysis, patients with human epidermal growth factor receptor (HER2)-positive breast cancer were more likely to develop breast pCR than patients with HER2-negative disease (odds ratio = 15.3; CI, 2.9-156.6; P = .001). At a median follow-up of 5 years, our study showed an overall low rate of local recurrence or distant metastasis with 5-year DFS of 92.3%. There was a numerically higher disease recurrence rate in patients without a breast pCR compared to those with a breast pCR, though this difference was not statistically significant (4.2% vs 12%; hazard ratio = 3.41; 95% CI, 0.53-22.1; P = .2). CONCLUSIONS:Our study showed that of the 124 patients who had pCR in the nodes, only 58% had a pCR in the breast, which is lower than the 80% rate seen in National Surgical Adjuvant Breast and Bowel Project B51. While our study found no significant difference in 5-year DFS between those with breast pCR versus not, given that patients with ER/PR+/HER2- disease are less likely to achieve breast pCR and tend to recur at later timepoints, further research is needed to evaluate the benefit of regional nodal irradiation in patients with a pCR in the axilla without a pCR in the breast.

PURPOSE/OBJECTIVE(S)/OBJECTIVE:Radiation therapy (RT) positioning and planning are vital to minimizing toxicity in patients with synchronous bilateral breast cancer (SBBC). We studied clinical outcomes and setup reproducibility in SBBC patients treated in the prone position. MATERIALS/METHODS/METHODS:This retrospective study analyzed SBBC patients treated prone between 2012-2022. Demographics, clinical RT dose/field, dosimetry, on-treatment imaging, toxicity, and outcomes data were collected. RT delivery was standardized, with left breast treated first. After 2014, radiochromic (GaF) films were placed fractions 1-5 to evaluate field overlap, prompting re-simulation or re-planning if consistent overlap was detected. Positional shifts during setup were collected for bilateral whole breast irradiation (WBI) and partial breast irradiation (PBI). RESULTS:45 patients were included. Median age was 67 years old and median follow-up was 64 months. 35, 5, and 5 patients received bilateral WBI (1 with low axilla), bilateral PBI, a combination of WBI and PBI, respectively. The most common WBI dose was 40.5 Gy, with a simultaneous tumor bed boost to 48 Gy. PBI patients received 30 Gy in 5 fractions (n=4) or 40.05 Gy in 15 fractions (n=1). All patients who developed grade 2 (17.7%) and grade 3 (2%) dermatitis received bilateral WBI except for 1. 6 patients had acute dermatitis in the sternal area with overlap on GaF seen in 2 patients. Of 20 patients with late toxicity follow-up, 25% had late grade 1-2 dermatitis (20% received WBI). One patient recurred locally and distantly. Mean positional shifts were mostly sub-centimeter or sub-degree. Only 10% of patients had field overlap on GaF. CONCLUSION/CONCLUSIONS:To our knowledge, this is the first study examining patients treated for SBBC in the prone position. Prone bilateral RT is feasible with minimal shifts and overlap. However, higher rates of acute dermatitis occurred in bilateral WBI patients (vs. PBI), and overlap wasn't seen on GaF in all patients who developed midline dermatitis.

PURPOSE/OBJECTIVE:Intensity-modulated radiation therapy (IMRT) is increasingly used for total body irradiation (TBI) due to its ability to deliver myeloablative doses while sparing radiosensitive organs. To enable consistent evaluation in future National Clinical Trials Network (NCTN) studies, the xxx Hematologic Malignancies Working Group (HMWG) convened IMRT-TBI experts and NCTN leaders to develop consensus recommendations for standardized multi-institutional implementation. METHODS:A 47-question survey was distributed to NRG institutions utilizing IMRT-TBI to characterize current planning and delivery practices. Responses were analyzed for commonalities and variations. A multidisciplinary working group reviewed survey findings, developed consensus-based technical and clinical recommendations, and created a standardized template for IMRT-TBI integration into NCTN protocols. Topics included simulation, contouring, planning, organ-at-risk (OAR) constraints, quality assurance (QA), image-guided radiotherapy (IGRT), commissioning, credentialing, and safeguards for clinical trial conduct. RESULTS:Eight institutions with collective experience treating more than 750 patients with IMRT-TBI responded. Most centers used VMAT to the upper body with anteroposterior/posteroanterior (AP/PA) fields to the lower body, 3-9 isocenters, lower dose rates for lung fields (100-200 MU/min), and no physical bolus. Common OAR constraints included lungs mean dose <8 Gy, kidneys mean dose <6-8 Gy, and lenses maximum dose <90% of prescription. All respondents used auto-segmentation; 50% used auto-planning. QA practices varied, but patient-specific QA passing rates were high (>95% with 3%/2 mm gamma). Consensus recommendations for clinical trial use were established, including standardized PTV definitions, OAR sparing goals, dosimetric constraints, QA requirements, and credentialing processes. CONCLUSIONS:IMRT-TBI offers the potential for reduced toxicity and improved dose precision compared with 2D-TBI, but its complexity requires careful standardization in multi-institutional trials. The xxx HMWG and collaborating NCTN experts developed the consensus-based technical and clinical framework for incorporating IMRT-TBI into cooperative group protocols. Adoption of these recommendations will facilitate consistent implementation and enable rigorous evaluation of outcomes.

PURPOSE/OBJECTIVE:Improved communication by clinicians at initial consultation may reduce anxiety and psychological burden of cancer treatment. Based on our pilot qualitative study which involved semi-structured interviews with breast cancer patients, we developed Curietherapy User eXperience (CurieUx), an educational tool integrating augmented reality display technology into radiation oncology consultations. METHODS:We developed an interactive 3-dimensional hologram using an augmented reality desktop display. Animated modules on patient-specific anatomy (breast, regional lymph nodes, organs-at-risk), simulation, linear accelerator, and positioning (prone and breath holding techniques) were created. Patients with newly diagnosed breast cancer undergoing initial radiation oncology consult were prospectively enrolled. Likert scale surveys on anxiety (NIH PROMIS), radiation knowledge, and augmented reality experience (modified IBM technology usability survey) were administered to patients before and after consultation. RESULTS:A total of 40 newly diagnosed breast cancer patients were enrolled in this proof-of-concept study at a median age of 67 years. Patients reported decreases in multiple components of anxiety after consultation with the CurieUx platform, including in fearfulness (2.13 vs 1.78, p=0.003), uneasiness (2.28 vs. 1.82, p=0.008), nervousness (2.41 vs 2.06, p=0.005), and tenseness (2.28 vs 1.87, p=0.004). Patients reported significant increases in radiation knowledge across multiple domains, including treatment machine (2.35 vs 4.7, p<0.001), radiation (2.7 vs 4.58, p<0.001), positioning (2.49 vs 4.68, P<0.001), and confidence (2.4 vs 4.3, p<0.001). An overwhelming majority of patients had positive experiences (4 or 5 on Likert scale) using the CurieUx hologram display as part of consultation, including its ease of understanding (97%), clarity (93%), comfort (100%), value (97%), and satisfaction (97%). CONCLUSION/CONCLUSIONS:Curietherapy User eXperience is a valuable educational tool that reduces patient anxiety and promotes radiation knowledge. In this feasibility study, the vast majority of patients found the incorporation of CurieUx into the existing radiation oncology consultation practice to be a valuable addition to the process.