A cost-effective, machine learning-based new unified risk-classification score (NU-CATS) for patients with endometrial cancer.

INTRODUCTION: Treatment for endometrial cancer (EC) is increasingly guided by molecular risk classifications. Here, we aimed at using machine learning (ML) to incorporate clinical and molecular risk factors to optimize risk assessment. METHODS: The Cancer Genome Atlas-Uterine Corpus Endometrial Carcinoma (n = 596), Memorial Sloan Kettering-Metastatic Events and Tropisms (n = 1315) and the American Association for Cancer Research Project Genomics Evidence Neoplasia Information Exchange (n = 4561) datasets were used to identify genetic alterations and clinicopathological features. Software packages including Keras, Pytorch, and Scikit Learn were tested to build artificial neural networks (ANNs) with a binary output as either intra-abdominal metastatic progression ('1') vs. non-metastatic ('0'). RESULTS: Black patients with EC have worse prognosis than White patients, adjusting for TP53 or POLE mutation status. Over 75% of Black patients carry TP53 mutations as compared to approximately 40% of White patients. Older age is associated with an increasing likelihood of TP53 mutation, high risk histology, and distant metastasis. For patients above age 70, 91% of Black and 60% of White EC patients carry TP53 mutations. A ML-based New Unified classifiCATion Score (NU-CATS) that incorporates age, race, histology, mismatch repair status, and TP53 mutation status showed 75% accuracy in prognosticating intra-abdominal progression. A higher NU-CATS is associated with an increasing risk of having positive pelvic or para-aortic lymph nodes and distant metastasis. NU-CATS was shown to outperform Leiden/TransPORTEC model for estimating risk of FIGO Stage I/II disease progression and survival in Black EC patients. CONCLUSION: The NU-CATS, a ML-based, cost-effective algorithm, incorporates diverse clinicopathologic and molecular variables of EC and yields superior prognostication of the risk of nodal involvement, distant metastasis, disease progression, and overall survival.

TARGIT-R (Retrospective): 5-Year Follow-Up Evaluation of Intraoperative Radiation Therapy (IORT) for Breast Cancer Performed in North America.

BACKGROUND: Intraoperative radiation therapy (IORT) has been investigated for patients with low-risk, early-stage breast cancer. The The North American experience was evaluated by TARGIT-R (retrospective) to provide outcomes for patients treated in "real-world" clinical practice with breast IORT. This analysis presents a 5-year follow-up assessment. METHODS: TARGIT-R is a multi-institutional retrospective registry of patients who underwent lumpectomy and IORT between the years 2007 and 2013. The primary outcome of the evaluation was ipsilateral breast tumor recurrence (IBTR). RESULTS: The evaluation included 667 patients with a median follow-up period of 5.1 years. Primary IORT (IORT at the time of lumpectomy) was performed for 72%, delayed IORT (after lumpectomy) for 3%, intended boost for 8%, and unintended boost (primary IORT followed by whole-breast radiation) for 17% of the patients. At 5 years, IBTR was 6.6% for all the patients, with 8% for the primary IORT cohort and 1.7% for the unintended-boost cohort. No recurrences were identified in the delayed IORT or intended-boost cohorts. Noncompliance with endocrine therapy (ET) was associated with higher IBTR risk (hazard ratio [HR], 3.67). Patients treated with primary IORT who were complaint with ET had a 5-year IBTR rate of 3.9%. CONCLUSION: The local recurrence rates in this series differ slightly from recent results of randomized IORT trials and are notably higher than in previous published studies using whole-breast radiotherapy for similar patients with early-stage breast cancer. Understanding differences in this retrospective series and the prospective trials will be critical to optimizing patient selection and outcomes going forward.

Treatment Strategies for Oligometastatic Breast Cancer.

OPINION STATEMENT: Oligometastatic breast cancer, typically defined as the presence of 1-5 metastases, represents an intermediate state between locally advanced and widely metastatic disease. Emerging research suggests that oligometastatic cancer has a unique molecular signature distinct from widely metastatic disease, and that it carries a superior prognosis. Owing to its more limited capacity for widespread progression, oligometastatic disease may benefit from aggressive ablative therapy to known metastases. Options for ablation include surgical excision, radiofrequency ablation, and hypofractionated image-guided radiotherapy (HIGRT). The phase II SABR-COMET trial, which enrolled patients with oligometastatic disease of multiple histologies and randomized them to HIGRT vs. standard of care, found a notable survival advantage in favor of HIGRT. Other data suggest that HIGRT may synergize with immunotherapy by releasing powerful cytokines that increase anti-tumor immune surveillance and by recruiting tumor infiltrating lymphocytes, helping to overcome resistance to therapy. There are many ongoing trials exploring the role of ablative therapy, most notably HIGRT, with or without immunotherapy, for the treatment of oligometastatic breast cancer.We believe that patients with oligometastatic breast cancer should be offered enrollment on prospective clinical trials when possible. Outside the context of a clinical trial, we recommend that select patients with oligometastatic breast cancer be offered treatment with a curative approach, including ablative therapy to all sites of disease if it can be safely accomplished. Currently, selection criteria to consider for ablative therapy include longer disease-free interval from diagnosis to metastasis (>2 years), fewer metastases, and fewer involved organs. Undoubtedly, new data will refine or even upend our understanding of the definition and optimal management of oligometastatic disease.

A simple dosimetric approach to spatially fractionated GRID radiation therapy using the multileaf collimator for treatment of breast cancers in the prone position.

The purpose of this study was to explore the treatment planning methods of spatially fractionated radiation therapy (SFRT), commonly referred to as GRID therapy, in the treatment of breast cancer patients using multileaf collimator (MLC) in the prone position. A total of 12 patients with either left or right breast cancer were retrospectively chosen. The computed tomography (CT) images taken for the whole breast external beam radiation therapy (WB-EBRT) were used for GRID therapy planning. Each GRID plan was made by using two portals and each portal had two fields with 1-cm aperture size. The dose prescription point was placed at the center of the target volume, and a dose of 20 Gy with 6-MV beams was prescribed. Dose-volume histogram (DVH) curves were generated to evaluate dosimetric properties. A modified linear-quadratic (MLQ) radiobiological response model was used to assess the equivalent uniform doses (EUD) and therapeutic ratios (TRs) of all GRID plans. The DVH curves indicated that these MLC-based GRID therapy plans can deliver heterogeneous dose distribution in the target volume as seen with the conventional cerrobend GRID block. The plans generated by the MLC technique also demonstrated the advantage for accommodating different target shapes, sparing normal structures, and reporting dose metrics to the targets and the organs at risks. All GRID plans showed to have similar dosimetric parameters, implying the plans can be made in a consistent quality regardless of the shape of the target and the size of volume. The mean dose of lung and heart were respectively below 0.6 and 0.7 Gy. When the size of aperture is increased from 1 to 2 cm, the EUD and TR became smaller, but the peak/valley dose ratio (PVDR) became greater. The dosimetric approach of this study was proven to be simple, practical and easy to be implemented in clinic.

Association of chemotherapy and radiotherapy sequence with overall survival in locoregionally advanced endometrial cancer.

OBJECTIVE: The optimal adjuvant management of women with FIGO Stage III-IVA endometrial cancer (EC) is unclear. While recent prospective data suggest that treatment with pelvic radiotherapy (RT) prior to chemotherapy (CT) is not associated with a survival benefit compared to CT alone, no prospective randomized trial has included a treatment arm in which CT is given before RT. METHODS: An observational cohort study was performed on women with FIGO Stage III-IVA Type 1 (grade 1-2, endometrioid) EC who underwent hysterectomy and received multi-agent CT and/or RT from 2004 to 2014 at Commission on Cancer-accredited hospitals. Multivariable parametric accelerated failure time models were performed to estimate the association of sequence of adjuvant CT and RT with overall survival (OS) using propensity score-adjusted matched cohorts. RESULTS: Of 5795 women identified, 1260 (21.7%) received RT only, 2465 (42.5%) received CT only, 593 (9.7%) received RT before CT, and 1506 (26.0%) received RT after CT. Women who received RT after CT experienced significantly longer 5-year OS than women who received RT before CT (5-year OS: 80.1% vs 73.3%; time-ratio (TR) = 1.37, 95% CI = 1.18-1.58, P < 0.001), CT only (68.9%; TR = 1.33, 95% CI = 1.19-1.48, P < 0.001), or RT only (64.5%, TR = 1.50, 95% CI = 1.32-1.70, P < 0.001). CONCLUSIONS: For women with advanced EC, treatment with multi-agent CT followed by RT is associated with longer OS compared with treatment with RT followed by CT or either treatment alone. These hypothesis-generating data support inclusion in future prospective trials of regimens in which multi-agent CT starts prior to RT.

Clinical implementation, logistics and workflow guide for MRI image based interstitial HDR brachytherapy for gynecological cancers.

Interstitial brachytherapy (IBT) is often utilized to treat women with bulky endometrial or cervical cancers not amendable to intracavitary treatments. A modern trend in IBT is the utilization of magnetic resonance imaging (MRI) with a high dose rate (HDR) afterloader for conformal 3D image-based treatments. The challenging part of this procedure is to properly complete many sequenced and co-related physics preparations. We presented the physics preparations and clinical workflow required for implementing MRI-based HDR IBT (MRI-HDR-IBT) of gynecologic cancer patients in a high-volume brachytherapy center. The present document is designed to focus on the clinical steps required from a physicist's standpoint. Those steps include: (a) testing IBT equipment with MRI scanner, (b) preparation of templates and catheters, (c) preparation of MRI line markers, (d) acquisition, importation and registration of MRI images, (e) development of treatment plans and (f) treatment evaluation and documentation. The checklists of imaging acquisition, registration and plan development are also presented. Based on the TG-100 recommendations, a workflow chart, a fault tree analysis and an error-solution table listing the speculated errors and solutions of each step are provided. Our workflow and practice indicated the MRI-HDR-IBT is achievable in most radiation oncology clinics if the following equipment is available: MRI scanner, CT (computed tomography) scanner, MRI/CT compatible templates and applicators, MRI line markers, HDR afterloader and a brachytherapy treatment planning system capable of utilizing MRI images. The OR/procedure room availability and anesthesiology support are also important. The techniques and approaches adopted from the GEC-ESTRO (Groupe Européen de Curiethérapie - European Society for Therapeutic Radiology and Oncology) recommendations and other publications are proven to be feasible. The MRI-HDR-IBT program can be developed over time and progressively validated through clinical experience, this document is expected to serve as a reference workflow guideline for implementing and performing the procedure.

Development of a nomogram to predict the clinical impact of a postexcision preirradiation mammogram.

We aimed to better quantify the impact of a postexcision preirradiation mammogram (PPM), first by identifying factors associated with abnormal results and then incorporating these findings into a nomogram. Beginning February 2011, our institution made a practice change to obtain a PPM on all patients with any calcifications identified. A total of 530 patients underwent a PPM. Suspicious abnormalities were reported in 61 patients (11.5%), with the PPM leading to a change in management in 47 instances (8.9%). A nomogram was created based on patient and tumor characteristics to identify patients most likely to have an abnormal PPM.

Risk Factors Leading to Complications in Early-Stage Breast Cancer Following Breast-Conserving Surgery and Intraoperative Radiotherapy.

OBJECTIVE: The aim of this study was to evaluate outcomes after breast-conserving surgery (BCS) and intraoperative radiotherapy (IORT), and to identify risk factors associated with complications. MATERIALS/METHODS: We evaluated patients with early-stage breast cancer treated from January 1, 2011 to January 31, 2014 with BCS and IORT at a single institution. The presence of breast cancer recurrences, complications, or fat necrosis were assessed at subsequent follow-up visits using physical examination and breast imaging. RESULTS: Overall, 113 patients, of whom three were undergoing bilateral treatments, were identified. The median length of time for IORT was 29 min and 36 s (range 15:50-59:00). Fifteen patients received additional external beam radiotherapy (EBRT), and the median follow-up was 40.3 months (range 1.6-58.3) for all patients. To date, one biopsy-proven ipsilateral recurrence has been noted (0.9%), for which the patient elected to undergo a mastectomy. Nine patients were found to have wound complications (7.7%) and two had fat necrosis (1.7%) on follow-up. Of all the evaluated risk factors, only applicator size (p < 0.01) had a statistically significant association with an increase in complications. CONCLUSIONS: With a short follow-up, IORT appears to be a safe treatment modality for a select group of patients, leading to a reasonable increase in operating room time and complication rates following BCS. The utilization of larger applicators at the time of IORT was associated with an increase in wound complications and fat necrosis.

Therapeutic analysis of Intrabeam-based intraoperative radiation therapy in the treatment of unicentric breast cancer lesions utilizing a spherical target volume model.

It is postulated that the outcomes in treating breast cancer with intraoperative radiotherapy (IORT) would be affected by the residual cancer cell distribution within the tumor bed. The three-dimensional (3D) radiation doses of IntrabeamTM (IB) IORT with a 4-cm spherical applicator at the energy of 50 and 40 kV were calculated. The modified linear quadratic model (MLQ) was used to estimate the radiobiological responses of the cancer cells and interspersed normal tissues with various radiosensitivities. By comparing the average survival fraction of normal tissues in IB-IORT and uniform dose treatment for the same level of cancer cell killing, the therapeutic ratios (TRs) were derived. The equivalent uniform dose (EUD) was found to increase with the prescription dose and decrease with the cancer cell infiltrating distance. For 50 kV beam at the 20 Gy prescription dose, the EUDs are 18.03, 16.49 and 13.56, 11. 29, and 9.28 Gy respectively, for 1.5, 3.0, 6.0, 9, and 15.0 mm of the cancer cell infiltrating distance into surrounding tissue. The dose rate of 50 kV is at least 1.87× higher than that of 40 kV beam. The EUDs of 50 kV beam are up to 15% higher than that of the 40 kV beam. The TR increases with the prescription dose, but decreases with the distance of cancer cell infiltration distance. Average TRs of 50 kV beam are up to 30% larger than that of 40 kV beam. In conclusion, IB-IORT can provide a possible therapeutic advantage on sparing more normal tissue compared with the External Beam IORT (EB-IORT) for shallowly populated unicentric breast lesion. Our data suggest that IB-IORT dose size should be adjusted based on the individual patient's cancer cell infiltrating distance for delivering an effective dose, one dose-fits-all regimen may have undertreated some patients with large cancer infiltrating distance.

Receipt of vaginal brachytherapy is associated with improved survival in women with stage I endometrioid adenocarcinoma of the uterus: A National Cancer Data Base study.

BACKGROUND: Randomized controlled trials have consistently shown that the use of postoperative radiotherapy (RT) for stage I endometrial cancer leads to a reduction in the incidence of pelvic recurrences without a corresponding reduction in overall mortality. It was hypothesized that a reduction in mortality associated with the receipt of RT could be identified in a large data set with greater statistical power. METHODS: Women with surgically staged IA or IB endometrial adenocarcinoma who were treated with total hysterectomy between 2003 and 2011 were identified in the National Cancer Data Base. Chi-square tests and multivariate logistic regression were performed to analyze factors associated with the treatment type. A survival analysis was performed with log-rank testing, Cox proportional hazards regression, and Kaplan-Meier estimates. RESULTS: A total of 44,309 eligible women were identified (33,380 at stage IA and 10,929 at stage IB): 88.4% of the women with stage IA tumors and 51.6% of the women with stage IB tumors received no RT. Older age, comorbid disease, a higher histologic grade, and a larger tumor size were independently associated with an increase in mortality. The receipt of vaginal brachytherapy (VB) was independently associated with a reduction in mortality for both stage IA disease (hazard ratio [HR], 0.81; 95% confidence interval [CI], 0.67-0.97) and stage IB disease (HR, 0.62; 95% CI, 0.51-0.74). CONCLUSIONS: Analyses of this large database support the utility of postoperative VB for many women with stage I endometrial cancer. Unfortunately, RT appears to be underused in this population. Greater adherence to consensus guidelines may lead to improved outcomes. Cancer 2016;122:3724-31. © 2016 American Cancer Society.

TARGIT-R (Retrospective): North American Experience with Intraoperative Radiation Using Low-Kilovoltage X-Rays for Breast Cancer.

BACKGROUND: Single-dose intraoperative radiotherapy (IORT) is an emerging treatment for women with early stage breast cancer. The objective of this study was to define the frequency of IORT use, patient selection, and outcomes of patients treated in North America. METHODS: A multi-institutional retrospective registry was created, and 19 institutions using low-kilovoltage IORT for the treatment of breast cancer entered data on patients treated at their institution before July 31, 2013. Patient selection, IORT treatment details, complications, and recurrences were analyzed. RESULTS: From 2007 to July 31, 2013, a total of 935 women were identified and treated with lumpectomy and IORT. A total of 822 patients had at least 6 months' follow-up documented and were included in the analysis. The number of IORT cases performed increased significantly over time (p < 0.001). The median patient age was 66.8 years. Most patients had disease that was <2 cm in size (90 %) and was estrogen positive (91 %); most patients had invasive ductal cancer (68 %). Of those who had a sentinel lymph node procedure performed, 89 % had negative sentinel lymph nodes. The types of IORT performed were primary IORT in 79 %, secondary IORT in 7 %, or planned boost in 14 %. Complications were low. At a median follow-up of 23.3 months, crude in-breast recurrence was 2.3 % for all patients treated. CONCLUSIONS: IORT use for the treatment of breast cancer is significantly increasing in North America, and physicians are selecting low-risk patients for this treatment option. Low complication and local recurrence rates support IORT as a treatment option for selected women with early stage breast cancer.

Race, Prevalence of POLE and POLD1 Alterations, and Survival Among Patients With Endometrial Cancer.

Importance: Black patients with endometrial cancer (EC) in the United States have higher mortality than patients of other races with EC. The prevalence of POLE and POLD1 pathogenic alterations in patients of different races with EC are not well studied. Objective: To explore the prevalence of and outcomes associated with POLE and POLD1 alterations in differential racial groups. Design, Setting, and Participants: This retrospective cohort study incorporated the largest available data set of patients with EC, including American Association for Cancer Research Project GENIE (Genomics Evidence Neoplasia Information Exchange; 5087 participants), Memorial Sloan Kettering-Metastatic Events and Tropisms (1315 participants), and the Cancer Genome Atlas Uterine Corpus Endometrial Carcinoma (517 participants), collected from 2015 to 2023, 2013 to 2021, and 2006 to 2012, respectively. The prevalence of and outcomes associated with POLE or POLD1 alterations in EC were evaluated across self-reported racial groups. Exposure: Patients of different racial groups with EC and with or without POLE or POLD1 alterations. Main Outcomes and Measures: The main outcome was overall survival. Data on demographic characteristics, POLE and POLD1 alteration status, histologic subtype, tumor mutation burden, fraction of genome altered, and microsatellite instability score were collected. Results: A total of 6919 EC cases were studied, of whom 444 (6.4%), 694 (10.0%), and 4869 (70.4%) patients were self-described as Asian, Black, and White, respectively. Within these large data sets, Black patients with EC exhibited a lower weighted average prevalence of pathogenic POLE alterations (0.5% [3 of 590 cases]) compared with Asian (6.1% [26 of 424]) or White (4.6% [204 of 4520]) patients. By contrast, the prevalence of POLD1 pathogenic alterations was 5.0% (21 cases), 3.2% (19 cases), and 5.6% (255 cases) in Asian, Black, and White patients with EC, respectively. Patients with POLD1 alterations had better outcomes regardless of race, histology, and TP53 alteration status. For a total of 241 clinically annotated Black patients with EC, a composite biomarker panel of either POLD1 or POLE alterations identified 7.1% (17 patients) with positive outcomes (1 event at 70 months follow up) in the small sample of available patients. Conclusions and Relevance: In this retrospective clinicopathological study of patients of different racial groups with EC, a composite biomarker panel of either POLD1 or POLE alteration could potentially guide treatment de-escalation, which is especially relevant for Black patients.

Single Fraction Radiation for Myeloid Sarcoma Is as Effective as Multi-Fraction Regimens for Tumor Regression and Control.

INTRODUCTION/BACKGROUND: Myeloid sarcoma is a rare extramedullary manifestation of immature myeloid/monocyte cells. Radiotherapy (RT) yields good local control, but data on different fractionation schemes are limited. The goal of this retrospective study was to share our institutional experience and assess volumetric regression with differential fractionation. MATERIALS AND METHODS: We evaluated patients treated for myeloid sarcoma between 2000 and 2019 and categorized them into Group A (treated with RT) and Group B (no RT). We assessed local control using cumulative incidence function analysis. Post-treatment imaging sequences were analyzed for volumetric calculations. RESULTS: Forty-four patients with 80 lesions were assessed. Twenty-three patients with 52 lesions received RT (Group A), and 6 lesions received a single fraction of RT. There were 2 instances of local progression in Group A and 8 in Group B, with a cumulative incidence function estimate of local progression in Group A of 2.4% at 1 year and 6.9% at 2 years, significantly reduced compared to 29.7% and 35.5% in Group B, respectively (hazard ratio 0.13 [95% confidence interval 0.030.63], P = .011). No lesion treated with a single fraction of RT developed local progression. Volumetric analysis for 19 chronologically followed lesions (including 3 treated with a single fraction) revealed no difference in regression between single or multi-fraction treatment. CONCLUSION: RT for myeloid sarcoma yields excellent local control and may be as effective in a single fraction as more protracted courses, though this requires validation. For a diagnosis associated with poor survival, a single palliative fraction may be optimal with potential for higher utilization.

Impact of p53, HIF1a, Ki-67, CA-9, and GLUT1 Expression on Treatment Outcomes in Locally Advanced Cervical Cancer Patients Treated With Definitive Chemoradiation Therapy.

PURPOSE/OBJECTIVE: The objective of this study was to assess the association between pretreatment p53, hypoxia inducible factor 1a (HIF1a), Ki-67, carbonic anhydrase-9 (CA-9), and glucose transporter 1 (GLUT1) expression in locally advanced cervical cancer patients treated definitively with concurrent chemoradiation therapy (CRT) and treatment outcomes including overall survival (OS), progression-free survival (PFS), local-regional control (LC), and distant metastases-free survival (DMFS). PATIENTS AND METHODS: Twenty-eight patients treated definitively and consecutively for cervical cancer with CRT had p53, HIF1a, Ki-67, CA-9, and GLUT1 protein expression assessed and scored semiquantitatively by 3 pathologists, blinded to the treatment outcomes. Outcomes were stratified by p53 (H-score: <15 vs. ≥15), HIF1a (H-score: <95 vs. ≥95), Ki-67 (labeling index <41% vs. ≥41%), CA-9 (H-score: <15 vs. ≥15), and GLUT1 (H-score: <175 vs. ≥175) expression. OS, PFS, LC, and DMFS rates were calculated using the Kaplan-Meier method, and differences between groups were evaluated by the log-rank test. RESULTS: Notable clinical characteristics of the cohort included median age of 51 years (range: 32 to 74 y), FIGO stage IIB disease (57.2%), clinical node-negative disease (64.3%), squamous cell carcinoma (89.3%), and adenocarcinoma (10.7%). Treatment outcomes included 5-year OS (57.2%), PFS (48.1%), LC (72.1%), and DMFS (62.9%). For HIF1a H-score <95 and ≥95, the 5-year OS (52.0% and 68.4%, P=0.58), PFS (53.0% and 40.9%, P=0.75), LC (71.6% and 68.2%, P=0.92), and DMFS (59.7% and 52.0%, P=0.91) were not significantly different. For Ki-67 labeling index <41% and ≥41%, the 5-year OS (44.9% and 66.6%, P=0.35), PFS (38.9% and 55.4%, P=0.53), LC (57.7% and 85.7%, P=0.22), and DMFS (67.3% and 61.0%, P=0.94) were not significantly different. For CA-9 H-score <15 and ≥15, the 5-year OS (54.4% and 66.7%, P=0.39), PFS (57.3% and 40.0%, P=0.87), LC (70.0% and 70.0%, P=0.95), and DMFS (70.0% and 46.7%, P=0.94) were not significantly different. For GLUT1 H-score <175 and ≥175, the 5-year OS (43.6% and 43.6%, P=0.32), PFS (55.6% and 49.5%, P=0.72), LC (72.9% and 71.5%, P=0.97), and DMFS (62.5% and 59.6%, P=0.76) were not significantly different. For p53, H-score <15 and ≥15, the 5-year OS (62% and 53%), PFS (63% and 30.3%), LC (87.5% and 52%), and DMFS (79.6% and 41.6%). CONCLUSIONS: In this study population, HIF1a, Ki-67, CA-9, and GLUT1 expression did not predict treatment response or outcomes in locally advanced cervical cancer patients treated definitively with CRT. There was a nonstatistically significant trend towards worse outcomes with p53 expression.

Development of a gynecologic brachytherapy curriculum and simulation modules to improve radiation oncology trainees' skills and confidence.

PURPOSE: Brachytherapy in the management of cervical cancer is directly linked to improved survival. Unfortunately, we continue to see a decline in its utilization. A recent survey of U.S. residents demonstrated limited caseload as the greatest barrier to achieving independence in brachytherapy practice. To improve residents' brachytherapy skills and confidence in performing brachytherapy independently, a gynecologic brachytherapy simulation course was developed and tested. METHODS AND MATERIALS: The gynecologic brachytherapy curriculum and simulation modules were developed using a combination of didactic education, self-study, practicums, and patient-centered cases. The simulation modules consisted of 2-h sessions. The first hour occurred within a simulated OR environment, where residents independently performed all aspects of applicator insertion in a cadaver model. The second hour consisted of contouring, dosimetric planning, and treatment evaluation. A brachytherapy training survey developed by the Association of Residents in Radiation Oncology was given before and after the course. RESULTS: The perceived ability to perform brachytherapy independently for a given disease site correlated directly with number of cases performed. Most residents believed that after performing five cases they would be capable of performing additional cases independently (10 of 18). All strongly agreed (8 of 18) or agreed (10 of 18) this to be true after 15 cases. Compared with survey data before the brachytherapy simulation course, trainees felt that their ability to independently perform brachytherapy (p < 0.001) improved. CONCLUSIONS: A brachytherapy simulation course can be used to gain further experience in a controlled environment. Our results demonstrate that gynecologic brachytherapy simulation increased trainees' confidence in performing the procedures independently.

Prognostic Significance of Nuclear Factor Kappa B Expression in Locally Advanced Cervical Cancer Patients Treated Definitively With Concurrent Chemoradiation.

OBJECTIVES: Nuclear factor kappa B (NFkB) is a transcription factor shown to confer treatment resistance in tumors. A previous report suggested an association between pretreatment NFkB and poorer outcomes for cervical cancer patients treated with chemoradiation therapy (CRT). We aimed to validate their findings in a larger patient cohort. MATERIALS AND METHODS: This Institutional Review Board approved study included patients with locally advanced cervical cancer patients treated with CRT. Evaluation of both nuclear and cytoplasmic immunoreactivity for NFkB was scored semiquantitatively by 3 pathologists. Cytoplasmic positivity incorporated both the intensity and percentage of immunoreactivity in invasive carcinoma (H-score), whereas nuclear positivity was assessed by percentage of positive cells. Outcomes were stratified by NFkB overexpression and tumor characteristics. Overall survival (OS), progression-free survival (PFS), distant metastases-free survival (DMFS), and local regional control (LC) were obtained using Kaplan-Meier and differences between groups were evaluated by the log-rank test. Hazard ratios were obtained using Cox regression for both univariate and multivariate analyses. RESULTS: The mean age was 51 years old and most (78.57%) had locally advanced disease. Five-year OS, PFS, LC, and DMFS in the entire cohort were 57.18% (confidence interval [CI], 34.06%-74.82%), 48.07% (CI, 25.50%-67.52%), 72.11% (CI, 49.96%-85.73%), and 62.85% (CI, 36.33%-80.82%), respectively. There was no significant association between NFkB expression (H-index ≥180) and 3-year and 5-year OS (P-value=0.34), PFS (P-value=0.21), LC (P-value=0.86), or DMFS (P-value=0.18). CONCLUSIONS: Our study demonstrated that cytoplasmic NFkB-p65 expression (H-index ≥180) was associated with a nonstatistically significant trend toward poor clinical outcomes in locally advanced cervical cancer patients treated definitively with CRT.

Photon GRID Radiation Therapy: A Physics and Dosimetry White Paper from the Radiosurgery Society (RSS) GRID/LATTICE, Microbeam and FLASH Radiotherapy Working Group.

The limits of radiation tolerance, which often deter the use of large doses, have been a major challenge to the treatment of bulky primary and metastatic cancers. A novel technique using spatial modulation of megavoltage therapy beams, commonly referred to as spatially fractionated radiation therapy (SFRT) (e.g., GRID radiation therapy), which purposefully maintains a high degree of dose heterogeneity across the treated tumor volume, has shown promise in clinical studies as a method to improve treatment response of advanced, bulky tumors. Compared to conventional uniform-dose radiotherapy, the complexities of megavoltage GRID therapy include its highly heterogeneous dose distribution, very high prescription doses, and the overall lack of experience among physicists and clinicians. Since only a few centers have used GRID radiation therapy in the clinic, wide and effective use of this technique has been hindered. To date, the mechanisms underlying the observed high tumor response and low toxicity are still not well understood. To advance SFRT technology and planning, the Physics Working Group of the Radiosurgery Society (RSS) GRID/Lattice, Microbeam and Flash Radiotherapy Working Groups, was established after an RSS-NCI Workshop. One of the goals of the Physics Working Group was to develop consensus recommendations to standardize dose prescription, treatment planning approach, response modeling and dose reporting in GRID therapy. The objective of this report is to present the results of the Physics Working Group's consensus that includes recommendations on GRID therapy as an SFRT technology, field dosimetric properties, techniques for generating GRID fields, the GRID therapy planning methods, documentation metrics and clinical practice recommendations. Such understanding is essential for clinical patient care, effective comparisons of outcome results, and for the design of rigorous clinical trials in the area of SFRT. The results of well-conducted GRID radiation therapy studies have the potential to advance the clinical management of bulky and advanced tumors by providing improved treatment response, and to further develop our current radiobiology models and parameters of radiation therapy design.

Patterns of Failure and Survival Outcomes after Total Lymphoid Irradiation and High-Dose Chemotherapy with Autologous Stem Cell Transplantation for Relapsed or Refractory Classical Hodgkin Lymphoma.

PURPOSE: The patterns of failure and long-term outcomes of patients with relapsed or refractory classical Hodgkin lymphoma treated with total lymphoid irradiation (TLI) and high-dose chemotherapy followed by autologous stem cell transplantation (aSCT) are reported. METHODS AND MATERIALS: Patients with biopsy-proven primary refractory or relapsed classical Hodgkin lymphoma who received salvage chemotherapy and accelerated hyperfractionated TLI before high-dose chemotherapy and aSCT were included. Patterns of failure were delineated after fusing pretransplant planning computed tomography to the scan reporting the first failure. Survival rates were computed using the Kaplan-Meier method. Multivariate analysis using proportional hazards regression was done to determine prognostic factors for overall survival (OS) and progression-free survival (PFS). RESULTS: Between 1993 and 2016, 89 patients underwent salvage treatments. Twenty patients failed at a median of 6.1 months after aSCT. Posttreatment scans were available for 16 patients who failed in a combined 43 different sites, 11 of which were extranodal. Patients failed at multiple sites, mostly within radiation fields. The 5-, 10-, and 15-year OS rates were 72.8%, 68.0%, and 58.3%; PFS rates were 73.3%, 68.5%, and 58.7%; event-free survival rates were 72.3%, 67.5%, and 57.8% respectively. The 5- and 10- year actuarial local control rates were both 77.6%. Complete response (CR) to salvage chemotherapy was associated with statistically significant improvements in OS and PFS. Eight patients developed secondary malignancies; 5 were hematologic and 3 were solid tumors. CONCLUSIONS: Most failures were within the irradiated volume, which reflects the treatment-resistant disease biology. As part of a conditioning regimen, TLI yields good survival outcomes, particularly in patients achieving CR before transplant. However, need for RT in this setting should be assessed and new strategies should be developed to combat the treatment-resistant biology, especially in patients with less than CR after salvage chemotherapy.

Determining the Organ at Risk for Lymphedema After Regional Nodal Irradiation in Breast Cancer.

PURPOSE: Lymphedema after regional nodal irradiation is a severe complication that could be minimized without significantly compromising nodal coverage if the anatomic region(s) associated with lymphedema were better defined. This study sought to correlate dose-volume relationships within subregions of the axilla with lymphedema outcomes to generate treatment planning guidelines for reducing lymphedema risk. METHODS AND MATERIALS: Women with stage II-III breast cancer who underwent breast surgery with axillary assessment and regional nodal irradiation were identified. Nodal targets were prospectively contoured per Radiation Therapy Oncology Group guidelines for field design. The axilla was divided into 8 distinct subregions that were retrospectively contoured. Lymphedema outcomes were assessed by arm circumferences. Multivariate Cox proportional hazards regression assessed patient, surgical, and dosimetric predictors of lymphedema outcomes. RESULTS: Treatment planning computed tomography scans for 265 women treated between 2013 and 2017 were identified. Median post-radiation therapy follow-up was 3 years (interquartile range [IQR], 1.9-3.6). Dose to the axillary-lateral thoracic vessel juncture (ALTJ; superior to level I) was most associated with lymphedema risk (maximally selected rank statistic = 6.3, P < .001). The optimal metric was ALTJ minimum dose (Dmin) <38.6 Gy (3-year lymphedema rate 5.7% vs 37.4%, P <.001), although multiple parameters relating to sparing of the ALTJ were highly correlated. Multivariate analysis confirmed ALTJ Dmin <38.6 Gy (hazard ratio [HR], 0.13; P < .001), body mass index (HR, 1.06/unit; P = .002), and number of lymph nodes removed (HR, 1.08/node; P < .001) as significant predictors. Women with ALTJ Dmin <38.6 Gy maintained median V45Gy of 99% in the supraclavicular (IQR, 94-100%), 100% in level III (IQR, 97%-100%), 98% in level II (IQR, 86%-100%), and 91% in level I (IQR, 75%-98%) nodal basins. CONCLUSIONS: Anatomic studies suggest the ALTJ region is typically traversed by arm lymphatics and appears to be an organ at risk in breast radiation therapy. Ideally, avoidance of the ALTJ may be feasible while simultaneously encompassing breast-draining nodal basins. Confirmation of this finding in future prospective studies is needed.

Development and Validation of a Nomogram to Predict Lymphedema After Axillary Surgery and Radiation Therapy in Women With Breast Cancer From the NCIC CTG MA.20 Randomized Trial.

PURPOSE: Regional nodal irradiation for women with breast cancer is known to be an important risk factor for the development of upper extremity lymphedema, but tools to accurately predict lymphedema risks for individual patients are lacking. This study sought to develop and validate a nomogram to predict lymphedema risk after axillary surgery and radiation therapy in women with breast cancer. METHODS AND MATERIALS: Data from 1832 women accrued on the MA.20 trial between March 2000 and February 2007 were used to create a prognostic model with National Cancer Institute Common Toxicity Criteria Version 2.0 grade 2 or higher lymphedema as the primary endpoint. Multivariable logistic regression estimated model performance. External validation was performed on data from a single large academic cancer center (N = 785). RESULTS: In the MA.20 trial cohort, 3 risk factors were predictive of lymphedema risk: body mass index (adjusted odds ratio, 1.05 per unit body mass index; 95% confidence interval [CI], 1.03-1.08, P < .001), extent of axillary surgery (adjusted odds radio for 8-11 lymph nodes removed, 3.28 [95% CI, 1.53-7.89] P = .004; 12-15 lymph nodes, 4.04 [95% CI, 1.76-10.26] P = .002; ≥16 nodes, 5.08 [95% CI, 2.26-12.70] P < .001), and extent of nodal irradiation (adjusted odds radio for limited, 1.66 [95% CI, 1.08-2.56] P = .02; for extensive, 2.31 [95% CI, 1.28-4.10] P = .004). A nomogram was created from these data that predicted lymphedema risk with reasonable accuracy confirmed by both internal (concordance index, 0.69; 95% CI, 0.64-0.74) and external validation (concordance index, 0.71; 95% CI, 0.66-0.76). CONCLUSIONS: The nomogram created from the MA.20 randomized trial data using clinical information may be useful for lymphedema screening and risk stratification for therapeutic intervention trials.