The Impact on Peer Mentorship After Implementation of a Competency-Based Residency Curriculum in Canadian Radiation Oncology Training Programs.

Purpose: Peer mentorship provides professional and personal support between physicians with similar experiences and levels of training. While peer mentorship has shown to benefit academic success and professional growth, little data has examined contextual factors, such as curricular change, that may affect the quality of these relationships. This study aims to explore the impact of a new, nationwide radiation oncology (RO) residency curriculum, known as competence by design (CBD), on peer mentorship experiences between Canadian RO residents. Methods and Materials: A qualitative study, with a social constructivist approach, was conducted with 2 groups of Canadian RO residents. The first were those in the academic year before CBD implementation (non-CBD cohort), and the second were those in the inaugural year of CBD (CBD cohort). Semistructured 1-on-1 interviews were conducted to explore experiences of peer mentorship as it related to curriculum change. Interviews were transcribed and analyzed with deductive and inductive methods until data saturation. Results: Between April and December 2021, 14 participants (6 non-CBD and 8 CBD residents) from 8 out of 10 eligible English-speaking RO training programs across Canada participated. Three major themes were identified: (1) the CBD cohort identified fewer opportunities for peer mentorship, with specific concerns regarding new evaluation processes and uncertainty about the later stages of training; (2) there was minimal impact on specialty-specific learning; and (3) peer mentorship thrived when occurring as spontaneous in-person interactions. Conclusions: Inaugural residents of a CBD curriculum perceived fewer opportunities for peer mentorship. There were specific concerns about new evaluative processes, though this did not affect specialty-specific learning. Peer mentorship was most impactful as informal and in-person interactions. Our findings suggest that unintended consequences of curriculum change may be mitigated by improving communication about new training objectives and increasing opportunities for informal interactions between residents.

A Qualitative Analysis of Medical Student Reflections Following Participation in a Canadian Radiation Oncology Studentship.

Exposure to radiation oncology in medical school curricula is limited; thus, mentorship and research opportunities like the Dr. Pamela Catton Summer Studentship Program attempt to bridge this gap and stimulate interest in the specialty. In 2021, the studentship was redesigned as virtual research, mentorship, and case-based discussions due to the COVID-19 pandemic. This study explores the impact of COVID-19 on the studentship, on students' perceptions of the program, and on medical training and career choice. Fifteen studentship completion essays during 2021-2022 were obtained and anonymized. Thematic analysis was performed to interpret the essays with NVivo. Two independent reviewers coded the essays. Themes were established by identifying connections between coded excerpts. Consensus was achieved through multiple rounds of discussion and iteratively reviewing each theme. Representative quotes were used to illustrate the themes. The themes confirmed the studentship was feasible during the pandemic. Perceived benefits of the program included mentorship and networking opportunities; gaining practical and fundamental knowledge in radiation oncology; developing clinical and research skills; and creating positive attitudes towards radiation oncology and the humanistic aspect of the field. The studentship supported medical specialty selection by helping define student values, shaping perceptions of the specialty, and promoting self-reflection upon students' personal needs. This study informs future iterations of the studentship to promote radiation oncology in Canadian medical school curricula. It serves as a model for studentships in other specialties that have limited exposure and similar challenges with medical student recruitment.

The Role of Adjuvant Radiotherapy for the Treatment of Resected High-Risk Stage III Cutaneous Melanoma in the Era of Modern Systemic Therapies.

Modern adjuvant systemic therapies (STs) have revolutionized the management of stage III melanoma. Currently, the role of adjuvant radiotherapy (RT) remains unclear. In this single-center retrospective study, patients with clinically detectable stage III melanoma with high-risk features for lymph node basin (LNB) recurrence and whose tumors were fully resected with complete lymphadenectomy (CLD) between 2010 and 2019 were assessed. We determined the cumulative incidence (CIF) of LNB recurrence and any disease recurrence or progression using competing risk analysis. A total of 108 patients were identified; the median age was 59 years (24-92), and 74 (69%) were men. A total of 51 (42%) received adjuvant RT, 22 (20%) received adjuvant ST, and 35 (32%) received no adjuvant therapy. The advent of ST changed clinical practice, with a significant increase in the use of adjuvant ST and a decrease in the use of RT when comparing practice patterns before and after 2015 (p < 0.001). The 3-year CIF of LNB recurrence was similar in patients treated with adjuvant RT (6.3%) and adjuvant ST (9.8%). The 3-year CIF of any disease recurrence or progression was lower in patients receiving adjuvant ST (24%) compared to those receiving adjuvant RT (52%) or no adjuvant therapy (55%, p = 0.06). Three-year overall survival (OS) was not significantly different in patients treated with ST compared to those not treated with any ST (p = 0.118). Despite ST replacing RT as the dominant adjuvant treatment modality, this change in practice has not resulted in increased LNB recurrence for patients at high risk of LNB recurrence following CLD.

Minimizing the Risk of Acute Skin Toxicity Due to Hip Prosthesis Avoidance in Prostate Radiation Therapy.

Limiting the entrance dose through hip prostheses to improve dosimetric accuracy can result in unfavorable skin toxicity. We propose a volumetric modulated arc therapy solution that strikes a better balance between dose accuracy and skin dosimetry. Our current planning strategy limits the entrance dose through hip prostheses using stringent optimization objectives on an avoidance structure. Avoidance efficiency is evaluated by recalculating the plan with prosthesis density set at 20 g/cc, and evaluating the loss of target coverage from increased attenuation. We require this loss to be ≤5% of the original values. This approach has resulted in an uncommon skin toxicity for a prostate-bed patient with bilateral hip prostheses. Thus, the dosimetric tradeoffs between skin dose and prosthesis avoidance were investigated by incrementally reducing prosthesis avoidance to achieve maximum skin doses (Dmax) between 30 and 50 Gy. When prosthesis avoidance is prioritized, the skin dose increases and the target dose coverage and conformity decrease. A large degradation in target coverage for plans with the lowest skin Dmax of 30 to 35 Gy indicates that a significant proportion of the target dose arises from beams entering the prostheses. The plan with a skin Dmax of 40 Gy provides a better compromise between skin and prosthesis entrance doses, with a <20% reduction in target coverage at an increased prosthesis density of 20 g/cm3. Skin dose needs to be considered when using prosthesis avoidance planning strategies. Allowing for a minimal dose through the prosthesis may be required to restrict skin dose and reduce the risk of toxicity.

Photon versus proton whole ventricular radiotherapy for non-germinomatous germ cell tumors: A report from the Children's Oncology Group.

PURPOSE: To determine if proton therapy reduces doses to cranial organs at risk (OARs) as compared to photon therapy in children with non-germinomatous germ cell tumors (NGGCT) receiving whole ventricular radiotherapy (WVRT). METHODS AND MATERIALS: Dosimetric data for patients with NGGCT prospectively enrolled in stratum 1 of the Children's Oncology Group study ACNS1123 who received 30.6 Gy WVRT were compared. Target segmentation was standardized using a contouring atlas. Doses to cranial OARs were compared between proton and photon treatments. Clinically relevant dose-volume parameters that were analyzed included mean dose and dose to 40% of the OAR volume (D40). RESULTS: Mean and D40 doses to the supratentorial brain, cerebellum, and bilateral temporal, parietal, and frontal lobes were statistically significantly lower amongst proton-treated patients, as compared to photon-treated patients. In a subgroup analysis of patients uniformly treated with a 3-mm planning target volume, patients who received proton therapy continued to have statistically significantly lower doses to brain OARs. CONCLUSIONS: Children treated with proton therapy for WVRT had lower doses to normal brain structures, when compared to those treated with photon therapy. Proton therapy should be considered for patients receiving WVRT for NGGCT.

Radiotherapy on-chip: microfluidics for translational radiation oncology.

The clinical importance of radiotherapy in the treatment of cancer patients justifies the development and use of research tools at the fundamental, pre-clinical, and ultimately clinical levels, to investigate their toxicities and synergies with systemic agents on relevant biological samples. Although microfluidics has prompted a paradigm shift in drug discovery in the past two decades, it appears to have yet to translate to radiotherapy research. However, the materials, dimensions, design versatility and multiplexing capabilities of microfluidic devices make them well-suited to a variety of studies involving radiation physics, radiobiology and radiotherapy. This review will present the state-of-the-art applications of microfluidics in these fields and specifically highlight the perspectives offered by radiotherapy on-a-chip in the field of translational radiobiology and precision medicine. This body of knowledge can serve both the microfluidics and radiotherapy communities by identifying potential collaboration avenues to improve patient care.

Modulatory role of prenatal alcohol exposure and adolescent stress on the response to arthritis challenge in adult female rats.

BACKGROUND: There are known environmental risk factors associated with rheumatoid arthritis; however, less is known regarding how the prenatal environment impacts later-life risk for rheumatoid arthritis. Based on preliminary clinical data suggesting that individuals with fetal alcohol spectrum disorder (FASD) are at higher risk for autoimmune disorders, this study investigated the modulatory impact of prenatal alcohol exposure (PAE) on the inflammatory disease profile in an adjuvant-induced arthritis rat model. METHODS: Pregnant rats received liquid ethanol or control diet throughout gestation. To model the increased exposure to stressors often experienced by individuals with FASD, adolescent offspring were exposed to chronic mild stress (CMS) or remained undisturbed. In adulthood, experimental arthritis was initiated and rats terminated either at the peak or following resolution from inflammation to assess endocrine, immune, and histopathological outcomes. FINDINGS: PAE rats had an increased incidence and severity of, and impaired recovery from, arthritis. Increased joint damage was observed in PAE animals, even in the face of apparent recovery from the clinical signs of arthritis, while it appeared that oestradiol may have a protective role. Moreover, with the combination of PAE and adolescent stress, increased macrophage density was detected in the synovium of PAE but not control rats. INTERPRETATION: These findings demonstrate that PAE alters the severity and course of arthritis, highlighting the potential immunomodulatory impact of adverse prenatal exposures. In particular, these data have implications for understanding preliminary data that suggest a heightened propensity for autoimmune disorders in individuals with FASD. FUNDING: This work was supported by: National Institutes of Health/National Institute on Alcohol Abuse and Alcoholism [R37 AA007789] and Kids Brain Health Network (KBHN; Canadian Networks of Centres of Excellence) to JW, a Natural Sciences and Engineering Research Council of Canada (NSERC) CGS-D to TSB and NIH/NIAAA R01 AA022460 to JW and TSB.

Stereotactic ablative radiotherapy in T1-2N0M0 small cell lung cancer: A systematic review and meta-analysis.

OBJECTIVES: Stereotactic ablative radiotherapy (SABR) is used to treat inoperable early-stage, node-negative small cell lung cancer (SCLC). We performed a systematic review and meta-analysis of the literature on SABR for T1-2N0M0 SCLC to summarize outcomes including local control (LC), overall survival (OS), recurrence rates, and toxicity. MATERIALS AND METHODS: This study was conducted in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) and MOOSE (Meta-analysis of Observational Studies in Epidemiology) guidelines. A systematic review of PubMed and EMBASE (inception to April 2021) was conducted. Two authors independently reviewed articles for inclusion and extracted study-level data. Random-effects meta-analysis was conducted using R (version 3.6.2) at a significance threshold of 0.05. RESULTS: Eleven studies were identified in the systematic review and seven (399 patients) were selected for meta-analysis. Inoperability was noted as the indication for SABR in 94% (75-100%) of patients. Median follow-up and tumor size were 19.5 months (11.9-32) and 24 mm (19-29), respectively. Chemotherapy and PCI use rates were 44.1% (95% confidence interval [CI], 27.0-61.9%) and 13.8% (95% CI, 0.4-41.2%), respectively. Local control was 97.3% (95% CI, 92.3-99.8%) at 1 year and 95.7% (95% CI, 74.2-100.0%) at 2 years. Overall survival was 86.3% (95% CI, 74.4-94.9%) at 1 year and 63.7% (95% CI, 45.7-79.9%) at 2 years. Nodal and distant recurrence rates were 17.8% (95% CI, 7.5-31.2%) and 26.9% (95% CI, 7.4-53.0%), respectively. The rates of grade 1, grade 2, and grade 3 toxicity (CTCAE) were 12.6% (95% CI, 6.7-19.9%), 6.7% (95% CI, 3.3-11.2%), and 1.4% (95% CI, 0.0-5.3%), respectively. No grade 4 or 5 events were observed across the studies. CONCLUSION: SABR for inoperable early-stage, node-negative SCLC is locally effective with limited toxicity. Prospective studies are required to further evaluate the role of SABR for patients at higher risk of toxicity with surgery or combined chemoradiation.

Reevaluating surgery and re-irradiation for locally recurrent pediatric ependymoma-a multi-institutional study.

BACKGROUND: The goal of this study was to evaluate extent of surgical resection, and timing and volume of re-irradiation, on survival for children with locally recurrent ependymoma. METHODS: Children with locally recurrent ependymoma treated with a second course of fractionated radiotherapy (RT2) from 6 North American cancer centers were reviewed. The index time was from the start of RT2 unless otherwise stated. RESULTS: Thirty-five patients were included in the study. The median doses for first radiation (RT1) and RT2 were 55.8 and 54 Gy, respectively. Median follow-up time was 5.6 years. Median overall survival (OS) for all patients from RT2 was 65 months. Gross total resection (GTR) was performed in 46% and 66% of patients prior to RT1 and RT2, respectively. GTR prior to RT2 was independently associated with improved progression-free survival (PFS) for all patients (HR 0.41, P = 0.04), with an OS benefit (HR 0.26, P = 0.03) for infratentorial tumors. Median PFS was superior with craniospinal irradiation (CSI) RT2 (not reached) compared to focal RT2 (56.9 months; log-rank P = 0.03). All distant failures (except one) occurred after focal RT2. Local failures after focal RT2 were predominantly in patients with less than GTR pre-RT2. CONCLUSIONS: Patients with locally recurrent pediatric ependymoma should be considered for re-treatment with repeat maximal safe resection (ideally GTR) and CSI re-irradiation, with careful discussion of the potential side effects of these treatments.

Comparison of Rapid to Standard Volumetric Modulated Arc Therapy for Palliative Radiotherapy in Lung Cancer Patients.

Patients with incurable lung cancer often present with debilitating symptoms that require urgent palliative radiotherapy. Volumetric modulated arc therapy (VMAT) provides several dosimetric advantages compared to basic non-conformal techniques, but involves complex planning resulting in a slower turn-around time for treatment. A simplified planning technique known as 'rapid VMAT' was developed with an aim to deliver palliative treatment to patients within 48 hours. The purpose of this study was to prospectively compare the dosimetric quality of rapid VMAT plans to standard VMAT plans. Fourteen consecutive rapid VMAT cases were re-planned de novo as per standard VMAT planning guidelines. Planning target volume (PTV) and organs at risk (OARs) were then compared. PTV coverage and dose to OARs including the spinal canal, lung, heart, and esophagus were similar between rapid and standard VMAT. Each plan was ready for treatment within 48 hours of the CT simulation. This study describes an expedited process for which palliative radiotherapy can be delivered to lung tumors with a similar robust quality that is provided for curative intent VMAT radiotherapy plans.

Current Management and Progress in Radiotherapy for Small Cell Lung Cancer.

Radiotherapy (RT) and chemotherapy continue to be widely utilized in small cell lung cancer (SCLC) management. In most limited stage (LS)-SCLC cases, the standard initial therapy remains concurrent chemoradiotherapy (CRT), typically with an etoposide and platinum-based regimen. Hyperfractionated twice daily (BID) RT remains the standard of care, though conventional daily (QD) RT is now a viable alternative supported by randomized evidence. In LS-SCLC patients who experienced good response to CRT, prophylactic cranial irradiation (PCI) remains the standard of care. Brain imaging, ideally with MRI, should be performed prior to PCI to screen for clinically apparent brain metastases that may require a higher dose of cranial irradiation. Platinum doublet chemotherapy alone is the historic standard initial therapy in extensive stage (ES)-SCLC. Addition of immunotherapy such as atezolizumab and durvalumab to chemotherapy is now recommended after their benefits were demonstrated in recent trials. In patients with response to chemotherapy, consolidation thoracic RT and PCI could be considered, though with caveats. Emergence of hippocampal avoidance cranial irradiation and SRS in SCLC patients may supplant whole cranial irradiation as future standards of care. Incorporation of novel systemic therapies such as immunotherapies has changed the treatment paradigm and overall outlook of patients with SCLC. This narrative review summarizes the current state, ongoing trials, and future directions of radiotherapy in management of SCLC.