PURPOSE:The study objective is to improve breast radiation therapy clinical workflows through a quality improvement approach rooted in implementation and improvement science methodologies. This study aims to demonstrate the effectiveness of these data-driven, multidisciplinary processes in optimizing complex clinical processes within radiation oncology. METHODS AND MATERIALS:A multidisciplinary stakeholder team applied an improvement science methodology to identify the root cause of inefficiencies in a pretreatment breast radiation therapy workflow. The intervention involved redesigning the task sequence and implementing an automated breast treatment planning solution to replace manual planning. The study evaluated the outcome measure of the target contouring time by the radiation oncologist and the treatment planning time by the medical dosimetrist. The outcome measures for 3 cohorts were analyzed: (1) the initial cohort with manual planning prior to any process change, (2) the pilot cohort with a limited stakeholder team for rapid change cycles with the modified clinical workflow and automated planning solution, and (3) a comprehensive rollout with the entire clinical team. The balancing quality measures of dosimetric compliance to dose-volume histogram planning objectives were also assessed across the 3 cohorts. RESULTS:From 2020 to 2022, 515 patients were included in the analysis. The task times from the initial cohort to the comprehensive rollout cohort were 0.2 (± 0.07) hours and 0.2 (± 0.03) hours for radiation oncologist contouring time and 8 (± 4) hours and 4 (± 1) hours for medical dosimetrist planning time, respectively. At the conclusion of the comprehensive rollout, total professional task time was decreased, and treatment plan quality was maintained. The approach successfully scaled from the smaller stakeholder team to the entire clinical workforce, demonstrating the effectiveness of implementation and improvement science methodologies. CONCLUSIONS:This study provides a comprehensive description and evaluation of a data-driven, sustainable process change in a multidisciplinary breast radiation therapy workflow. The methodology used serves as a model for clinical workflow optimization across radiation oncology settings.

Background and purpose. This study presents machine learning (ML) models that predict if deep inspiration breath hold (DIBH) is needed based on lung dose in right-sided breast cancer patients during the initial computed tomography (CT) appointment.Materials and methods. Anatomic distances were extracted from a single-institution dataset of free breathing (FB) CT scans from locoregional right-sided breast cancer patients. Models were developed using combinations of anatomic distances and ML classification algorithms (gradient boosting, k-nearest neighbors, logistic regression, random forest, and support vector machine) and optimized over 100 iterations using stratified 5-fold cross-validation. Models were grouped by the number of anatomic distances used during development; those with the highest validation accuracy were selected as final models. Final models were compared based on their predictive ability, measurement collection efficiency, and robustness to simulated user error during measurement collection.Results. This retrospective study included 238 patients treated between 2016 and 2021. Model development ended once eight anatomic distances were included, and the validation accuracy plateaued. The best performing model used logistic regression with four anatomic distances achieving 80.5% average testing accuracy, with minimal false negatives and positives (<27%). The anatomic distances required for prediction were collected within 3 min and were robust to simulated user error during measurement collection, changing accuracy by <5%.Conclusion. Our logistic regression model using four anatomic distances provided the best balance between efficiency, robustness, and ability to predict if DIBH was needed for locoregional right-sided breast cancer patients.

PURPOSE:This study investigated the cosmetic degradation and toxicity for an accelerated partial breast irradiation (APBI) prescription delivered in 5 fractions over 1 week and compared the outcomes with those of whole breast irradiation (WBI). METHODS AND MATERIALS:The trial was a multicenter, single-arm, phase 2 prospective cohort study. Eligible women 50 years of age or older with estrogen receptor-positive and human epidermal growth factor receptor 2-negative invasive ductal carcinoma or ductal carcinoma in situ after breast-conserving surgery received 27 Gy in 5 daily fractions of APBI. The primary endpoint was noninferiority of 2-year cosmesis using the RAPID trial's WBI arm as the control arm. A global consensus cosmetic score using a European Organisation for Research and Treatment of Cancer rating scale score of excellent, good, fair, or poor for each patient at baseline and 2 years was generated by a panel of 5 radiation oncologists using photographs of treated and untreated breasts. RESULTS:From 2016 to 2019, 298 eligible women were enrolled. By the 2-year follow-up, 76 patients had been lost or withdrawn and 3 had died, resulting in 219 patients available for complete, 2-year photographic cosmetic evaluation. The median follow-up for all participants was 4.7 years (IQR, 3.8-5.5 years). No patient had a fair or poor cosmetic score at the 2-year evaluation. Cosmesis was better or unchanged for 97% of patients and worse for 3% (excellent to good), and no cosmetic failures occurred. The confidence intervals were 0.88 (0.86-0.90) and 1.00 (0.99-1.00) for the RAPID and ACCEL trials, respectively. CONCLUSIONS:Cosmetic degradation with 5 daily treatments of the ACCEL trial's APBI intervention is noninferior to the WBI arm of the RAPID trial.

To inform clinical practice for women receiving post-mastectomy radiotherapy (PMRT), this study demonstrates the dosimetric impact of removing daily bolus on skin and subcutaneous tissue. Two planning strategies were used: clinical field-based (n = 30) and volume-based planning (n = 10). The clinical field-based plans were created with bolus and recalculated without bolus for comparison. The volume-based plans were created with bolus to ensure a minimum target coverage of the chest wall PTV and recalculated without bolus. In each scenario, the dose to superficial structures, including skin (3 mm and 5 mm) and subcutaneous tissue (a 2 mm layer, 3 mm deep from surface) were reported. Additionally, the difference in the clinically evaluated dosimetry to skin and subcutaneous tissue in volume-based plans were recalculated using Acuros (AXB) and compared to the Anisotropic Analytical Algorithm (AAA) algorithm. For all treatment planning strategies, chest wall coverage (V90%) was maintained. As expected, superficial structures demonstrate significant loss in coverage. The largest difference observed in the most superficial 3 mm where V90% coverage is reduced from a mean (± standard deviation) of 95.1% (± 2.8) to 18.9% (± 5.6) for clinical field-based treatments with and without bolus, respectively. For volume-based planning, the subcutaneous tissue maintains a V90% of 90.5% (± 7.0) compared to the clinical field-based planning coverage of 84.4% (± 8.0). In all skin and subcutaneous tissue, the AAA algorithm underestimates the volume of the 90% isodose. Removing bolus results in minimal dosimetric differences in the chest wall and significantly lower skin dose while dose to the subcutaneous tissue is maintained. Unless the skin has disease involvement, the most superficial 3 mm is not considered part of the target volume. The continued use of the AAA algorithm is supported for the PMRT setting.

Purpose/Objective(s) To determine the change in treatment resources due to the implementation of hypofractionated prescription regimen Materials/Methods All patients between January 1, 2012 and December 31, 2021 receiving curative intent breast radiotherapy at a tertiary cancer center were included. Plan and patient data were extracted from the patient database with the treatment planning system and direct database query. Treatment plan categorization was completed using data elements to include only curative intent. Treatment plans for seroma boost or supraclavicular irradiation were excluded to ensure this analysis did not double-count regional nodal irradiation contribution or confound boost with hypofractionation. Treatment delivery time is recorded in the database for each patient treatment delivered. Average patient treatment time per year was estimated by multiplying the average fractions each year by average time in the same year. The standard fractionation regimens (95% of patients) are 42.56 Gy in 16, 40 Gy in 16, 27 Gy in 5 (accelerated partial breast irradiation), and 26 Gy in 5 (FAST-Forward). In the analysis, implementation milestones are indicated for new prescription regimens and delivery technique changes including deep inspiration breath hold (DIBH) for left-sided patient treatments and daily verification imaging. Results A total of 6505 patients were included. Table 1 details the total number of patients per year, the average number of fractions treated per patient, and the average treatment time of each patient plan. The average total fractions per treatment decreased from 17.5 in 2012 to 10.9 in 2021. The average treatment delivery time increased from 12.9 minutes to 21.4 minutes. Conclusion In considering total treatment resources, the interplay between hypofractionation and modernization delivery techniques is complex. The impact of hypofractionation reduced the average number of fractions but total treatment resources are offset with the implementation of modern treatment delivery techniques. Hypofractionated prescription regimens reduce the time and travel commitment required of patients on an individual basis, contributing to person-centered care.

Purpose/Objective(s) To report final results of a clinical trial of APBI using intensity modulated radiotherapy (IMRT) to deliver 27 Gy in 5 daily fractions following breast conserving surgery (BCS) prospectively designed to assess the efficacy and cosmetic outcomes of a 1-week, APBI regimen among women with early breast cancer. Materials/Methods Women ≥ 50 years, with lymph node-negative, ER positive, HER-2 negative breast cancer or ductal carcinoma in situ (DCIS), ≤ 3cm diameter, following BCS with margins ≥ 2mm, and excellent or good baseline cosmesis received 27 Gy in 5 daily fractions to the seroma plus 1 cm CTV and 0.7 cm PTV margins. Clinical photographs, patient and provider cosmetic scores, breast fibrosis, telangiectasia and pain were collected prospectively, prior to RT and at 6 weeks, 1 and 2 years after RT. The primary endpoint was the proportion of women who retained Excellent or Good cosmesis at 2 years using the EORTC Cosmetic Rating System. Cosmetic failure was deterioration from Excellent or Good to Fair or Poor. A panel of 5 radiation oncologists independently assessed the cosmetic photographs. Secondary endpoints were rates and grades of breast fibrosis, telangiectasia, breast pain, ipsilateral breast tumor recurrence (IBRT), overall (OS), breast cancer-specific survival (BCSS) and subsequent mastectomy. Efficacy outcomes were assessed at clinic visits and by review of charts. ClinicalTrials.gov registration: NCT02681107. Results A total of 298 patients were treated between April 25, 2016, and October 31, 2019. At a median follow up of 48 months, the 4-year OS was 98.5% (95% CI 96.1% - 99.5%) and BCSS was 99.7% (95% CI 97.6% - 99.9%). The 4-year IBRT rate was 3.3% (95% CI 1.1% - 6.4%). There were 10 contralateral breast events for a 4-year rate of 3.9% (95% CI 2.2% - 6.9%). There were 10 ipsilateral and 6 contralateral mastectomies. Two patients died of unrelated causes prior to 2 years; 79 patients declined in-clinic attendance due to COVID or competing comorbidities and 217 women had 2-year cosmetic photographs and clinical assessments performed. Consensus of the photo-panel cosmesis at baseline was: Excellent: n=116 (53%), Good: n=102 (47%), Fair: n=1 (0.5%) and Poor: n=0. Consensus overall cosmesis at 2 years was: Excellent: n=141 (65%), Good: n=78 (35%), Fair: n=0 and Poor: n=0. Most patients had either improved (n=168; 77%) or no change (n=43; 20%) in cosmesis at 2-years. No patient had cosmetic failure but 6 (3%) had a change from Excellent to Good at 2 years. Most patients reported either no (79%) or mild (21%) pain, with no moderate or severe pain. Two patients (0.9%) had grade 2 fibrosis and 5 patients (2%) had visible telangiectasia that did not detract from overall cosmesis. Conclusion APBI using 27 Gy in 5 fractions using a conformal IMRT technique, achieved excellent 2-year cosmesis with minimal toxicity. The IBRT risk was comparable to the contralateral new breast cancer risk and to local recurrence rates of recently published early breast cancer trials.

PURPOSE:To demonstrate achievable dose for the left anterior descending artery (LAD) for left-sided breast cancer patients. METHODS:A retrospective analysis was conducted on all left-sided breast cancer patients receiving whole breast or post-mastectomy chest wall irradiation between 2013 and 2018. All patients in this study were treated with tangent-based techniques with the LAD prospectively contoured as routine clinical care. This large patient cohort was used to benchmark achievable mean doses to the LAD in the context of heart dose. The primary cohort of study were patients undergoing treatment with deep-inspiration breath-hold (DIBH), stratified by internal mammary nodes (IMN) inclusion. In all cases, the median (25th-75th percentile) is reported. RESULTS:A total of 1221 left-sided breast cancer patients were included in this study with 1045 in the DIBH cohort. The median heart mean dose for this cohort is 1.0 Gy (0.8-1.1). For patients treated in DIBH with IMNs included (n = 422), the median of the mean LAD dose is 3.6 Gy (2.9-4.4) and, for patients treated in DIBH with IMNs excluded (n = 623), the median of the mean LAD dose is 3.2 Gy (2.5-3.8). CONCLUSIONS:Appropriate respiratory management can be utilized to achieve low dose to the LAD for the majority of patients without compromising target coverage.

Chest wall bolus use has been standard practice in postmastectomy radiotherapy (PMRT) for patients without skin involvement, resulting in increased toxicity without strong data to show improved outcomes. Centers are moving away from use of bolus in PMRT, but the dosimetric effects have not been quantified. We aim to compare differences in dose between non-bolus and bolus plans to the superficial chest wall. We conducted a retrospective analysis on 30 patients treated with PMRT from December 2018 to June 2019 at our center. Patients received 4256 cGy in 16 fractions to chest wall and regional nodes using 4-field 3D conformal technique, 6 and/or 15 MV photons, and 0.5 cm bolus. The clinically planned datasets were used to generate non-bolus and bolus plans for each patient using the anisotropic analytical algorithm (AAA). The first 10 patients also had non-bolus and bolus plans generated using Acuros XB (AXB). Evaluation volumes were created by extracting surface layers from the clinical chest wall: 3 mm surface, 5 mm surface, and the layer between 3-5 mm depth. The 3 mm and 5 mm surface layers were chosen to match the most common definitions of skin in current breast studies, while the 3-5 mm layer represents the subcutaneous tissue immediately deep to the skin. Mean age, mean chest wall thickness, dermatitis grade level per CTCAE v5.0, and the mean V80%, V95%, and D2cc were reported for all plans. Mean patient age was 56 years (range 36 to 85 years). Mean chest wall thickness was 2.3 cm (1.1 to 6.5 cm). The most common beam energies were 6 and 15 MV photons (70%), followed by 15 MV alone (20%) and 6 MV alone (10%). Most had grade 1 (63%) and 2 (33%) dermatitis to the chest wall and axilla, with one patient developing grade 3 dermatitis. Mean V80%, V95%, and D2cc for the non-bolus and bolus plans were calculated using AAA (n = 30) and AXB (n = 10), as reported in the below table. While large differences exist in superficial layers, the 3-5 mm layer demonstrates consistent coverage for V80% with or without bolus. When AXB calculation is used, the differences are even more minimal in the 3-5 mm layer for both V80% and V95%. This result is expected based on AXB's superior superficial dose modelling. Our findings support the reduced use of bolus for PMRT patients without risk factors for dermal or dermal-lymphatic involvement.Tabled 1Abstract 2770; Table3 mm surface5 mm surface3-5 mm layerD2cc (%)Non-BolusBolusNon-BolusBolusNon-BolusBolusNon-BolusBolusAAA V80% (%)38.497.662.397.796.498.1107107AAA V95% (%)4.788.322.390.049.594.7AXB V80% (%)60.099.676.999.799.9100109109AXB V95% (%)23.796.249.397.286.298.7 Open table in a new tab

To parallel credentialing in external beam radiotherapy, credentialing in permanent seed implant brachytherapy should include a phantom delivery component that assesses an institution's capability in effectively delivering the prescription dose. In this work, a brachytherapy credentialing workflow is proposed that includes delivery to an implantable anthropomorphic phantom and assessment of an institution's seed implant accuracy. To demonstrate the assessment process, this credentialing workflow is applied to permanent breast seed implant (PBSI) brachytherapy.

PURPOSE:The aim of this study was to understand the international standard practice for radiation therapy treatment techniques and clinical priorities for institutions including the internal mammary lymph nodes (IMLNs) in the target volume for patients with synchronous bilateral breast cancer.METHODS:An international survey was developed to include questions that would provide awareness of favored treatment techniques, treatment planning and delivery resource requirements, and the clinical priorities that may lead to the utilization of preferred treatment techniques.RESULTS:Of the 135 respondents, 82 indicated that IMLNs are regularly included in the target volume for radiation therapy (IMLN-inclusion) when the patient is otherwise generally indicated for regional nodal irradiation. Of the 82 respondents that regularly include IMLNs, five were removed as those respondents do not treat this population synchronously. Of the 77 respondents, institutional standard of care varied significantly, though VMAT (34%) and combined static photon and electron fields (21%) were the most commonly utilized techniques. Respondents did preferentially select target volume coverage (70%) as the most important clinical priority, followed by normal tissue sparing (25%).CONCLUSION:The results of the survey indicate that the IMLN-inclusion for radiation therapy has not yet been comprehensively adopted. As well, no consensus on best practice for radiation therapy treatment techniques has been reached.

A 41-year-old woman presented with pT4dN1aM0, right-sided, inflammatory breast cancer. She had a co-morbid diagnosis of systemic lupus erythematosus (SLE) at the age of 20 and was found to have significant kidney involvement (lupus-associated nephritis) at the age of 28. She went on to receive six cycles of neoadjuvant chemotherapy consisting of fluorouracil, epirubicin, cyclophosphamide, and docetaxcel (FEC-D) after which she had radiographically stable disease. She then had definitive treatment with bilateral mastectomy. Pathology showed a 4-cm residual invasive ductal carcinoma in the right breast and three residual metastatic lymph nodes in the right axilla. After extensive discussions with the patient, which included counseling on the potential increased risk of radiation-induced side effects, she received 50.4 Gy in 28 fractions of adjuvant radiotherapy (RT) to the chest wall and regional lymphatics including the internal mammary chains (IMCs). To minimize the risk of pulmonary toxicity, RT field arrangement consisted of a field-in-field modulated supraclavicular anterior/posterior parallel pair matched to shallow, photon tangent pair with 0.5 cm bolus to the lateral aspect of the chest wall and two matched direct anterior electron fields of 9 MeV with 1 cm bolus and 12 MeV with 0.5 cm bolus medially to cover the remaining residual chest wall and IMCs. This was immediately followed by a boost of 7.5 Gy in three fractions delivered via a photon tangent pair with 1 cm bolus to an area 6 cm superior and inferior to the surgical scar. Total treatment time was 50 days. The patient tolerated the therapy well but she developed grade three acute dermatitis. There were no pulmonary, shoulder joint movement, or brachial plexus side effects. This case is unusual in that SLE is generally considered a contraindication for elective RT. However, given her high risk for breast cancer recurrence, RT was offered with additional caution to minimize lung dose. Having completed the treatment, the side effects experienced were no greater than what would be expected in someone who did not have a diagnosis of SLE.

underestimation of the TPS dose calculations at intermediate doses needs further investigation.Conclusions: The EBT3-based in-vivo skin dose measurements revealed an unexpected agreement with the TG43-based TPS for the patients exposed to higher skin doses.Intermediate calculated doses presented a large underestimation of the measured doses to the skin as evaluated by the EBT3 films.The clinical relevance of these findings requires further study.

A low-resource visually monitored deep inspiration breath-hold (VM-DIBH) technique was successfully implemented in our clinic to reduce cardiac dose in left-sided breast radiotherapy. In this study, we retrospectively characterized the chest wall and heart positioning accuracy of VM-DIBH using cine portal images from 42 patients. Central chest wall position from field edge and in-field maximum heart distance (MHD) were manually measured on cine images and compared to the planned positions based on the digitally reconstructed radiographs (DRRs). An in-house program was designed to measure left anterior descending artery (LAD) and chest wall separation on the planning DIBH CT scan with respect to breath-hold level (BHL) during simulation to determine a minimum BHL for VM-DIBH eligibility. Systematic and random setup uncertainties of 3.0 mm and 2.6 mm, respectively, were found for VM-DIBH treatment from the chest wall measurements. Intrabeam breath-hold stability was found to be good, with over 96% of delivered fields within 3 mm. Average treatment MHD was significantly larger for those patients where some of the heart was planned in the field compared to patients whose heart was completely shielded in the plan (p < 0.001). No evidence for a minimum BHL was found, suggesting that all patients who can tolerate DIBH may yield a benefit from it.