A Prospective Study Demonstrating Early Prediction of Skin Toxicity From Radiation Therapy Using Radiomic Features From Optical and Infrared Images.

PURPOSE: Approximately 90% of patients undergoing breast cancer radiation therapy experience skin toxicities that are difficult to classify and predict ahead of time. A prediction of toxicity at the early stages of the treatment would provide clinicians with a prompt to intervene. The objectives of this study were to evaluate the correlation between skin toxicity and radiomic features extracted from optical and infrared (thermal) images of skin, and to develop a model for predicting a patient's skin response to radiation. METHODS AND MATERIALS: Optical and infrared breast and chest-wall images were acquired daily during the course of radiation therapy, as well as weekly for 3 weeks after the end of treatment for 20 patients with breast cancer. Skin-toxicity assessments were conducted weekly until the patients' final visit. Skin color and temperature trends from histogram-based and texture-based radiomic features, extracted from the treatment area, were analyzed, reduced, and used in a cross-validation machine learning model to predict the patients' skin toxicity grades. RESULTS: A set of 9 independent color and temperature features with significant correlation to skin toxicity were identified from 108 features. The cross-validation accuracy of a cubic Support Vector Machine remained >85% and area under the receiver operating characteristic curve remained >0.75, when reducing the input imaging data to include only the sessions with a biologically effective dose not exceeding 30 Gy (approximately the first third to first half of the total treatment dose). CONCLUSIONS: The quantitative analysis of radiomic features extracted from optical and infrared (thermal) images of skin was shown to be promising for predicting skin toxicities.

Novel Technology Allowing Cone Beam Computed Tomography in 6 Seconds: A Patient Study of Comparative Image Quality.

PURPOSE: The goal of this study was to evaluate the image quality provided by a novel cone beam computed tomography (CBCT) platform (HyperSight, Varian Medical Systems), a platform with enhanced reconstruction algorithms as well as rapid acquisition times. Image quality was compared with both status quo CBCT for image guidance, and to fan beam CT (FBCT) acquired on a CT simulator (CTsim). METHODS AND MATERIALS: In a clinical study, 30 individuals were recruited for whom either deep inspiration (DIBH) or deep exhalation breath hold (DEBH) was used during imaging and radiation treatment of tumors involving liver, lung, breast, abdomen, chest wall, and pancreatic sites. All subjects were imaged during breath hold with CBCT on a standard image guidance platform (TrueBeam 2.7, Varian Medical Systems) and FBCT CT (CTsim, GE Optima). HyperSight imaging with both breath hold (HSBH) and free breathing (HSFB) was performed in a single session. The 4 image sets thus acquired were registered and compared using metrics quantifying artifact index, image nonuniformity, contrast, contrast-to-noise ratio, and difference of Hounsfield unit (HU) from CTsim. RESULTS: HSBH provided less severe artifacts compared with both HSFB and TrueBeam. The severity of artifacts in HSBH images was similar to that in CTsim images, with statistically similar artifact index values. CTsim provided the best image uniformity; however, HSBH provided improved uniformity compared with both HSFB and TrueBeam. CTsim demonstrated elevated contrast compared with HyperSight imaging, but both HSBH and HSFB imaging showed superior contrast-to-noise ratio characteristics compared with TrueBeam. The median HU difference of HSBH from CTsim was within 1 HU for muscle/fat tissue, 12 HU for bone, and 14 HU for lung. CONCLUSIONS: The HyperSight system provides 6-second CBCT acquisition with image artifacts that are significantly reduced compared with TrueBeam and comparable to those in CTsim FBCT imaging. HyperSight breath hold imaging was of higher quality compared with free breathing imaging on the same system. The median HU value in HyperSight breath hold imaging is within 15 HU of that in CTsim imaging for muscle, fat, bone, and lung tissue types, indicating the utility of image data for direct dose calculation in adaptive workflows.

A Delphi study and International Consensus Recommendations: The use of bolus in the setting of postmastectomy radiation therapy for early breast cancer.

Bolus serves as a tissue equivalent material that shifts the 95-100% isodose line towards the skin and subcutaneous tissue. The need for bolus for all breast cancer patients planned for postmastectomy radiation therapy (PMRT) has been questioned. The work was initiated by the faculty of the European SocieTy for Radiotherapy & Oncology (ESTRO) breast cancer courses and represents a multidisciplinary international breast cancer expert collaboration to optimize PMRT. Due to the lack of randomised trials evaluating the benefits of bolus, we designed a stepwise project to evaluate the existing evidence about the use of bolus in the setting of PMRT to achieve an international consensus for the indications of bolus in PMRT, based on the Delphi method.

Estimation of Annual Secondary Lung Cancer Deaths Using Various Adjuvant Breast Radiotherapy Techniques for Early-Stage Cancers.

PURPOSE: Secondary lung cancer (SLC) can offset the benefit of adjuvant breast radiotherapy (RT), and risks compound sharply after 25 to 30 years. We hypothesized that SLC risk is mainly an issue for early-stage breast cancer, and that lives could be saved using different RT techniques. PATIENTS AND METHODS: The SEER database was used to extract breast patient age, stage survival, and radiotherapy utilization over time and per stage and to assess the factors associated with increased SLC risk with a multivariable competing risk Cox model. The number of SLC was calculated using the BEIR model modified with patient survival, age, and use of RT from the SEER database. Stage distribution and number of new breast cancer cases were obtained from the NAACCR. Mean lung dose for various irradiation techniques was obtained from measurement or literature. RESULTS: Out of the 765,697 non-metastatic breast cancers in the SEER database from 1988 to 2012, 49.8% received RT. RT significantly increased the SLC risk for longer follow-up (HR=1.58), early stage including DCIS, stage I and IIA (HR = 1.11), and younger age (HR=1.061) (all p<0.001). More advanced stages did not have significantly increased risk. In 2019, 104,743 early-stage breast patients received radiotherapy, and an estimated 3,413 will develop SLC (3.25%) leading to an excess of 2,900 deaths (2.77%). VMAT would reduce this mortality by 9.9%, hypofractionation 26 Gy in five fractions by 38.8%, a prone technique by 70.3%, 3D-CRT APBI by 43.3%, HDR brachytherapy by 71.1%, LDR by 80.7%, and robotic 4π APBI by 85.2%. CONCLUSIONS: SLC after breast RT remains a clinically significant issue for early-stage breast cancers. This mortality could be significantly reduced using a prone technique or APBI.

The use of bolus in postmastectomy radiation therapy for breast cancer: A systematic review.

PURPOSE: Post mastectomy radiation therapy (PMRT) reduces locoregional recurrence (LRR) and breast cancer mortality for selected patients. Bolus overcomes the skin-sparing effect of external-beam radiotherapy, ensuring adequate dose to superficial regions at risk of local recurrence (LR). This systematic review summarizes the current evidence regarding the impact of bolus on LR and acute toxicity in the setting of PMRT. RESULTS: 27 studies were included. The use of bolus led to higher rates of acute grade 3 radiation dermatitis (pooled rates of 9.6% with bolus vs. 1.2% without). Pooled crude LR rates from thirteen studies (n = 3756) were similar with (3.5%) and without (3.6%) bolus. CONCLUSIONS: Bolus may be indicated in cases with a high risk of LR in the skin, but seems not to be necessary for all patients. Further work is needed to define the role of bolus in PMRT.

Radiation and/or endocrine therapy? Recurrence and survival outcomes in women over 70 with early breast cancer after breast-conserving surgery.

PURPOSE: Women over 70 with early breast cancer treated with breast-conserving surgery are typically offered adjuvant endocrine and radiation therapy. Prior studies have supported the omission of adjuvant radiation in this low-risk population. We sought to compare the effect of adjuvant treatment with endocrine therapy alone, radiation therapy alone or both versus no adjuvant treatment on local control and survival in this population. METHODS: Data were extracted on 1363 breast cancer patients over the age of 70 treated with a breast-conserving surgery from 2003 until 2018. 460 patients met inclusion criteria of pT1N0, invasive disease with negative margins and not treated with chemotherapy. The primary outcome of this population-based study was local recurrence-free survival at 5 and 10 years. RESULTS: Patients receiving no adjuvant therapy had worse local recurrence-free, loco-regional recurrence-free and disease-free survival than patients receiving at least one form of adjuvant therapy (p < 0.05). 5-year local recurrence rates were 0.8% in patients receiving both endocrine and radiation therapy, 1.5% in those receiving radiation alone, 4.2% in those receiving endocrine therapy alone and 12% in those receiving no adjuvant therapy. CONCLUSIONS: This study supports the benefit of some form of adjuvant therapy (radiation alone, endocrine therapy alone or both) in low-risk breast cancer patients over 70. Receiving no adjuvant therapy is associated with poorer outcomes. Many of these patients are candidates for Accelerated Partial Breast Irradiation which can be completed in less than a week. These patients should be offered radiation therapy, endocrine therapy or both.

Attitudes Towards Research During Residency Training: a Survey of Canadian Radiation Oncology Residents and Program Directors.

Radiation oncologists require clinical appraisal and research methodology skills, yet it is unclear how to develop these competencies during residency. We sought to attain a deeper understanding of the barriers that limit, as well as the factors that promote, engaging in research/scholarly activity during radiation oncology residency training in Canada. Following ethics approval, online surveys were circulated to all Canadian Radiation Oncology program directors and residents. Unidentifiable demographics, prior research experience, and descriptions of current research environment and barriers to engaging in research and scholarly activities were collected. Thirty-three percent (35/105) of residents and 71% (10/14) of program directors responded. Ninety-seven percent of residents, and 90% of program directors, agreed or strongly agreed that research/scholarly activity was an important part of residency training. While 66% of residents felt that there was a lack of protected time for research/scholarly activity, only 20% of program directors agreed this was a barrier (p = 0.011). While 94% of residents thought mentorship was important to completing high-quality research/scholarly activity, only 48% of respondents had a mentor. The highest barriers to completing research/scholarly activity projects were lack of protected time (for both residents and faculty), high resident clinical workload, and lack of experience in research skills. Canadian Radiation Oncology residents expressed strong enthusiasm to participate in research/scholarly activity, yet lack of protected time and competing demands were identified as major barriers. We suggest programs offer more protected time for research/scholarly activity, provide optional research methodology training, and support meaningful mentorship relationships.

Individualized Dose-Escalation of HDR Prostate Brachytherapy Implant to Decrease Required External Beam Radiation Dose: A Retrospective Feasibility Study.

PURPOSE: High-dose-rate brachytherapy (HDR-BT) is commonly combined with external beam radiation therapy (EBRT) for the treatment of localized prostate cancer. Escalating the HDR-BT dose as far as organ-at-risk (OAR) constraints allow, on a personalized basis, would allow for a reduction in EBRT dose while achieving similar total biologic equivalence. The primary objective of this study was to determine the dosimetric feasibility of escalating the HDR-BT dose from 15 Gy to 16 or 17 Gy while continuing to meet OAR constraints from the original 15 Gy plan on an individualized basis. METHODS AND MATERIALS: A total of 53 consecutive HDR-BT plans were retrospectively assessed to determine what percentage of plans could be reoptimized to deliver a dose of 16 Gy or 17 Gy, while meeting defined 15-Gy OAR constraints. Factors independently associated with dose escalation were examined. RESULTS: Thirty-nine plans (74%) and 2 plans (4%) were successfully escalated to a dose of 16 Gy and 17 Gy, respectively. Rectum V80 and urethra Dmax were independently predictive of the ability to dose escalate to 16 Gy. CONCLUSIONS: Individualized HDR-BT dose escalation beyond 15 Gy without compromising OAR constraints is dosimetrically feasible. This approach could allow for a corresponding reduction of EBRT fractions (ie, from 15 to 12 fractions) and would be beneficial in terms of resource savings for departments, convenience for patients, and potentially better tolerance of treatment with the expected reduction in biologically equivalent doses to OARs. A clinical trial is being developed to investigate the efficacy and tolerance of personalized HDR-BT/EBRT dose fractionation for localized intracapsular prostate cancer.

Burnout and Resiliency in Canadian Oncology Residents: A Nationwide Resident and Program Director Survey.

PURPOSE: This study aimed to measure the burnout rates and resiliency scores of Canadian oncology residents and advance the knowledge on resiliency and wellness training in Canadian oncology residency programs. METHODS AND MATERIALS: Online surveys were circulated to all Canadian radiation oncology, medical oncology, and hematology residents and program directors. Oncology resident burnout rates and resiliency scores were measured using the abbreviated Maslach Burnout Inventory and Connor-Davidson Resiliency Scale. Information with regard to pre-existing resiliency and wellness training programs as well as interest in and suggestions for potential resiliency and wellness activities was collected. RESULTS: The resident survey had a response rate of 30% (57 of 187 surveys sent). The average resiliency score on the Connor-Davidson Resiliency Scale was 65.4 (95% confidence interval, 62.2-68.6). A total of 24 responding residents (42.1%) met the defined burnout criteria. Low resiliency was significantly associated with a higher rate of burnout (P = .01). No specific demographics predicted low resiliency or high burnout. A total of 33 residents (58%) felt that they had not received adequate resiliency and wellness training. The program director survey had a response rate of 48% (20 of 42 surveys sent). Of the responding program directors, 50% indicated they had received no formal resiliency and wellness training. CONCLUSIONS: Canadian oncology residents demonstrate high rates of burnout and low resiliency compared with the general population, and similar burnout rates compared with U.S. radiation oncology residents and other resident groups. This is the first study to comprehensively report on the rates of burnout and resiliency in oncology residents and establishes a baseline to study resiliency and burnout in this population. The development of resiliency and wellness curricula, including mindfulness training and individualized activities, is warranted in this population, should be offered to all residents, and will be a mandatory component of the accreditation standards for Canadian residency programs as of 2018.

Transition to practice: creation of a transitional rotation for radiation oncology.

BACKGROUND: Implementation of Competence by Design (CBD) will require residency training programs to develop formalized "Transition to Practice" (TTP) experiences. A multidisciplinary group of Radiation Oncology stakeholders from tertiary care centres in Atlantic Canada were surveyed regarding a proposed TTP rotation. METHODS: The survey asked participants to quantitatively rank various learning objectives based on defined CanMEDS skills that are expected to be mastered by a graduating resident. Mean perceived importance scores were calculated for each objective as well as for their CanMEDS category. Specific written qualitative feedback was also collected. RESULTS: The survey was circulated to 59 participants with a response rate of 73%. The three objectives with the highest mean importance score were "Independently assessing and managing patients seen in consultation," "Developing and demonstrating communication skills with patients at an advanced level," and "Independently assessing and managing follow up patients," respectively from highest to lowest. The CanMEDS roles with the highest importance score was "Communicator." CONCLUSION: Quantitative and qualitative data from a multidisciplinary survey based on CanMEDS roles guided the implementation of a TTP rotation for PGY-5 residents at a tertiary care centre in Atlantic Canada. These results may be relevant to other training programs developing TTP experiences.

Endocarditis is not an Independent Predictor of Blood Transfusion in Aortic Valve Replacement Patients With Severe Aortic Regurgitation.

OBJECTIVE: This study sought to evaluate if the presence of endocarditis was independently associated with increased perioperative blood transfusion in patients undergoing aortic valve replacements (AVR) with aortic regurgitation. DESIGN: This was a retrospective study. SETTING: Large Canadian tertiary care hospital. PARTICIPANTS: Six hundred sixty-two consecutive patients with aortic regurgitation score of 3 or higher undergoing AVR from 1995 to 2012. INTERVENTIONS: No interventions were performed in this retrospective study. MEASUREMENTS AND MAIN RESULTS: After REB approval, data were obtained from a center-specific database. Univariate analysis was performed to identify variables that may be associated with transfusion of any allogeneic blood product perioperatively. A multivariate logistic regression was generated to identify independent predictors of perioperative transfusion. Unadjusted transfusion rates in patients with no endocarditis and with endocarditis were 32% and 70% (p<0.001), respectively. Independent predictors of any transfusion were moderate-to-severe preoperative anemia, preoperative renal failure, non-isolated AVR, age>70, urgent/emergent surgery, BMI<25, and female sex. Endocarditis was not an independent predictor of transfusion (OR = 0.748; 95% CI = 0.35-1.601). CONCLUSIONS: In patients undergoing AVR, unadjusted perioperative transfusion rates were higher when endocarditis was present. However, after adjustment, aortic valve endocarditis was not independently associated with blood transfusion. The authors' observation could be explained by the higher prevalence of many independent predictors of transfusion, such as comorbidities or more complex surgery, within the endocarditis group. Thus, AV endocarditis, in the absence of other risk factors, was not associated with increased perioperative transfusion risk.