Purpose:The study objective was to determine the representation of women in Canadian radiation oncology (RO) trainees and the radiation oncologist workforce over time. Methods and Materials:Gender data for Canadian RO trainees (residents and fellows) and radiation oncologists were collected from the Canadian Post-MD Education Registry (1994-2021) and Canadian Medical Association (1994-2019). Visa trainees were excluded. Gender parity was defined as a 1:1 female-to-male ratio. Descriptive statistics were used to summarize the data. Results:Female trainee proportions varied with 2 rising trend periods (1994-1998: 38%-43%, P = .93; 2002-2014: 35%-51%, P = .53) and 2 regression trend periods (1998-2002: 43%-35%, P = .83; 2014-2021: 52%-35%, P = .011). Gender parity was observed in RO trainees between 2012 and 2016. The annual number of RO trainees ranged from 66 to 173 with 2 near-parallel periods of gender-associated growth (1994-1996; 2002-2008) and regression (1997-2001; 2009-2016) followed by gender divergence (2017-2021) with increasing male and decreasing female trainees. Nearly all Canadian regions, except Ontario, reached 50% or higher female representation in RO trainees during the study period. In the radiation oncologist workforce, female representation increased from 20% (54/271) to 37% (217/582) between 1994 and 2019, and all regions and age groups demonstrated higher female representation over time. Within radiation oncologist subgroups, age <35 years old and Quebec region cohorts reached gender parity. Conclusions:Representation of women varied in Canadian RO trainees and has fallen since 2014, whereas female representation generally increased in the radiation oncologist workforce over time. Gender parity was observed in RO trainees, radiation oncologists <35 years old, and radiation oncologists in Quebec. Recent declining female representation among RO trainees is worrisome, and further study is warranted to identify potential gender-based barriers in attracting women to the specialty.

Purpose/Objective(s) Postmastectomy radiotherapy (RT) in patients with immediate breast reconstruction has well known risks of late complications including delayed wound healing, capsular contracture and poor cosmesis. For patients with a remote history of augmentation mammoplasty with implants (AMI) receiving adjuvant RT for breast cancer, the risk of complications is not well documented. At our institution, due to concerns about cosmesis, patients receiving adjuvant RT with remote AMI receive standard fractionation rather than hypofractionation. The purpose of this quality assurance project is to review outcomes for patients who received RT with remote AMI. Materials/Methods Using our radiation treatment planning interface, patients were identified who underwent adjuvant RT to the breast and/or regional nodes in 25 to 28 fractions between January 1, 2013, and December 31, 2019. Chart review was performed to determine demographics, type of reconstruction, complications, subsequent unexpected re-operations due to cosmesis, and dosimetry. EQD2 calculations were generated assuming an α/β=3.4 for normal breast tissue. Patients with and without cosmetic complication were compared for significance using the Mann Whitney U-test (two tailed, p<0.05). Results Thirty-two patients underwent RT with remote AMI. Four patients (12.5%) had documented cosmetic complications after adjuvant RT requiring reoperation. Complications included rupture (n=1), contracture (n=2), asymmetry (n=1). The mean time from radiation to reoperation was 697 days (353-1045 days). For patients with cosmetic complications, 75% received chemotherapy prior to RT while 32.1% of patients without complications received chemotherapy prior to RT. Doses ranged from 45-50 Gy in 25 fractions vs 50.4 Gy in 28 fractions. Boost doses ranged 10-16 Gy in 5-8 fractions. In addition to whole breast irradiation (WBI), one patient (25%) with cosmetic complications also received regional nodal RT while 6 patients without complications (21.5%) received adjuvant nodal RT. Of the patients with cosmetic complications, all received boost with electrons and none of the patients had bolus. The total EQD2 for WBI and boost was statistically higher in the group of patients requiring reoperation for cosmesis (57.8 Gy vs 52.3 Gy, p=0.02). Conclusion For our cohort of patients receiving RT after remote AMI, the rate of cosmetic complications requiring reoperation was low (12.5%). This rate is significantly lower than institutional and documented rates of cosmetic complications for patients with immediate reconstruction followed by adjuvant RT. While the sample size was small, it is worthwhile to note that patients receiving chemotherapy, boost, and a higher EQD2 were more likely to experience cosmetic complications. Future investigation should include prospective review of a larger cohort of patients with remote AMI and the risk profile of boost.

Radical treatment of localized prostate cancer in elderly patients may lead to unacceptable treatment-associated toxicities that adversely impact quality of life without improving survival outcomes. This study reports on a cohort of 54 elderly (>70 years) patients that received 4000–5000 cGy of palliative external beam radiotherapy (EBRT) as an alternative to androgen deprivation therapy (ADT). The primary outcome of interest was the period of ADT-free survival, and secondary outcomes included overall survival (OS) and metastases-free survival (MFS). Kaplan–Meier regression was used to estimate survival outcomes. Thirty-six (67%) patients achieved a break in ADT post-radiotherapy, with a median time to ADT reinitiation of 20 months. Common Terminology Criteria for Adverse Events (CTCAE) were limited to low-grade gastrointestinal (GI) or genitourinary (GU) toxicities, with no skin toxicities observed. Grade 1 GI toxicity was observed in 9 (17%) patients, and grades 1 and 2 GU toxicities were observed in 13 (24%) and 3 (6%) patients, respectively, with no higher-grade toxicities reported. Five-year MFS and OS were 56% and 78%, respectively. In summary, the treatment regimen was well-tolerated and achieved durable ADT-free survival in most patients. Dose-reduced EBRT appears to be a viable alternative to ADT in elderly patients with localized prostate cancer.

While men may live for many years with prostate cancer, symptoms associated with local extension and metastatic disease limit quality of life. Radical treatment for localized prostate cancer in elderly patients, age greater than 70, can sometimes lead to morbidity with less survival benefit. To mitigate this risk, androgen deprivation therapy-based approaches are often employed. At the study institution, a common clinical practice over the study period (>10 years) was to offer these patients palliative radiotherapy (RT) with doses up to 5000cGy in an attempt to control local disease, delay progression, and delay subsequent use of hormonal therapy. This study aimed to report on the benefits and toxicities associated with this RT treatment and whether it interrupted use of hormonal therapy. Using a patient information system, patients were identified with birthdate(s) on or before September 1, 1948, and having received radiotherapy treatment to the prostate with doses between 4000cGy and 5000cGy. Ethics approval was obtained and chart review performed to determine duration of hormonal treatment, radiation-related toxicity, PSA kinetics, and overall survival. 54 patients meeting the inclusion criteria for the study were identified. 53 (98%) had a pathologic confirmation of prostate cancer. Median time from pathologic diagnosis to administration of radiotherapy was 13 (13-31) months. Of the cohort, 36 (67%) patients did not receive continuous hormonal therapy. These patients had a median duration of combined neoadjuvant and adjuvant hormonal therapy of 18 months and a median time to re-initiation of hormonal therapy after radiotherapy of 20 months. No patients encountered CTCAE Grade 3 toxicities. There were no reported skin toxicities; 13 (24%) reported CTCAE Grade 1 Genitourinary (GU) toxicity, 3 (6%) CTCAE Grade 2 GU toxicity; and 9 (17%) reported CTCAE Grade 1 Gastrointestinal (GI) toxicity and 0% CTCAE Grade 2 GI toxicity. Kaplan-Meier estimated 5-year metastasis-free survival was 56%, and 5-year overall survival was 78%. Palliative radiotherapy to the prostate of up to 5000cGy was well tolerated in this cohort of elderly patients. In several patients, treatment breaks from androgen deprivation were achieved.

CARO VSM 2020 period, one out of 25 cancer cases presented with synchronous lung metastasis.Synchronous lung metastases most commonly arose from primary lung cancers, colorectal cancers, kidney cancers, pancreatic cancers and breast cancers.The proportion of cancer cases presenting with synchronous lung metastasis increased over time.At a median follow-up of 33 months, the median survival of all metastatic cases with synchronous lung metastasis was five months, and the two-year overall survival was 17.4%.De novo metastatic patients with lung metastases had worse overall survival (hazard ratio = 1.22 (1.21 to 1.23), p<0.001) compared to those with only extrapulmonary metastases, controlling for potential confounders.The presence of synchronous lung metastasis had the greatest negative impact on the overall survival of patients with metastatic cancers of the vulva and vagina (HR=2.32[1.86-2.91],p<0.001), testis (HR=2.14[1.69-2.70],p<0.001), oropharynx (excluding tongue and tonsil, HR=1.85 [1.26-2.73],p=0.019), tonsil ], p<0.001) and larynx (HR=1.71 [1.38-2.12],p<0.001).Conclusions: Synchronous lung metastasis occurs frequently and results in poorer patient outcomes.As treatment for lung metastases becomes more complicated, synchronous lung metastasis represents a growing public health concern.

For patients planned to undergo adjuvant postmastectomy radiotherapy (PMRT) for breast cancer, immediate breast reconstruction (IBR) has been considered a relative contraindication. Delayed wound healing, increased risk of capsular contracture, fat necrosis, poor cosmesis, and rates of reoperation are of concern. Patients who have undergone IBR at our institution with an indication for PMRT are prescribed extended fractionation as per institutional policy. The aim of this quality assurance project is to review rates of reoperation for patients who received PMRT after IBR with autologous tissue (AT), tissue expanders (TE), or permanent implants (PI). Using a patient information system, patients were identified who underwent adjuvant PMRT to the chest wall and regional nodes to a total dose of 5040 cGy in 28 fractions between January 1, 2013 and January 31, 2019. Radiotherapy plans were reviewed. Medical records were reviewed for patient and treatment characteristics, and unexpected reoperation rate. Seventy-three patients underwent IBR and PMRT. Eleven (15.1%) patients had AT, 24 (32.9%) had TE, and 38 (52.1%) had PI. Twenty-four patients (32.9%) had documented cosmetic complications (including capsular contracture and asymmetry) after PMRT requiring reoperation. Cosmetic complications (CC) leading to reoperation were documented in 45.5% of patients with AT, 37.5% of patients with TE, and 26.3% of patients with PI. The mean elapsed time from PMRT completion to reoperation for cosmetic complications was 12.3 months (range = 2.3-33.1 months). Most patients received either adjuvant or neoadjuvant chemotherapy (97.3%). Of the patients having CC leading to reoperation compared to those without complication, a higher proportion received neoadjuvant chemotherapy, but this difference was not statistically significant (39.1% vs 19.4%, p = 0.135). For patients with CC leading to reoperation, there was a significantly higher volume of chest wall receiving ≥5040 cGy (851cc vs 680 cc, p = 0.023). Bolus was slightly more common in patients with CC but this difference was not statistically significant (91.7% vs 81.5, p = 0.461). For our cohort of patients receiving PMRT after IBR, the rate of CC is comparable to those quoted elsewhere. Interestingly, for our cohort, patients having PI had the lowest rate of CC leading to reoperation compared those with AT and TE. Patients with CC had a higher volume of chest wall receiving ≥ 5040 cGy. Further dosimetric analysis is needed to determine if there is a correlation with capsule dose and cosmetic outcomes.

Objectives/HypothesisTo determine the volumetric changes in pharyngeal structures in patients with head and neck squamous cell carcinoma (HNSCC) treated with curative chemoradiation therapy (CRT). Patients treated with CRT for esophageal carcinoma (EC), where pharyngeal structures were not part of the radiation treatment fields, were controlled for dysphagia‐associated weight loss. We hypothesize that tissue volume alteration is a contributing factor of post‐CRT dysphagia.Study DesignCase series.MethodsThis study measured pre‐ and 1‐year posttreatment volumes of the base of tongue (BOT), parapharyngeal spaces, posterior pharyngeal constrictors (PCs), and retropharyngeal space (RPS) in patients undergoing CRT for HNSCC or EC treated January 1, 2012 to December 31, 2015. All HNSCC patients were treated to doses of 66 to 70 Gy in 30 to 33 fractions using intensity‐modulated radiotherapy techniques.ResultsOur cohort included 49 HNSCC and 11 EC patients. Within the HNSCC cohort, the PCs volume increased 1.55 cm3 (95% confidence interval [CI]: 0.77 to 2.34 cm3, P = .0002), RPS increased 1.22 cm3 (95% CI: 0.67 to 1.77 cm3, P < .0001), and BOT decreased 2.29 cm3 (95% CI: −0.20 to 4.79 cm3, P = .070). The EC cohort showed no significant volumetric changes for any anatomic space, with combined PCs and RPS volume changes statistically less than the HNSCC cohort (P = .031). There was no difference in mean body mass index reduction between groups (P = .10).ConclusionsVolumetric changes following CRT may play a role in posttreatment dysphagia. Our findings support loss of physiologic function from posterior pharynx tissue thickening combined with reduced pharyngeal constriction capacity, and BOT atrophy secondary to radiation effects contribute to dysphagia.Level of Evidence4Laryngoscope, 130:597–602, 2020

Global blood flow control is enabled by the conduction of charge along arteries. The distance over which electrical phenomena spread is governed by 3 factors, one being the ionic properties of vascular cells. In this study, we determined the role of inward rectifying K+ channels (KIR) in setting membrane conductance and charge spread along the arterial wall. Small middle cerebral arteries (~100 μm diameter) from hamster were probed with a standard conduction protocol. A focal KCl stimulus elicited a constrictor response that conducted robustly, with a decay constant of ~0.4 μm/100μm vessel length. Selective inhibition each K+ channel class had no effect on conduction, the exception being Ba2+ blockade of KIR, which facilitated decay (~1.6 μm/100μm vessel length). Patch clamp electrophysiology and Q‐PCR highlighted the presence of a KIR current in smooth muscle comprised of KIR2.1/2.2 subunits. The incorporation of this current into an electrical model revealed that it was too small to account for the change in conduction decay; consequently another KIR current must be present. Electrophysiology and Q‐PCR confirmed a second KIR current in the endothelium. Computational modeling subsequently confirmed that inhibiting both currents had a greater effect on conduction decay, the result of a sizable voltage shift increasing feedback from voltage dependent‐ and Ca2+ activated K+ channels. In summary, our observations indicate that KIR channels are present in endothelial and smooth muscle cells, and together these K+ conductances can tune electrical communication.Support or Funding InformationSupported by CIHR

Blood flow control is dependent on the initiation of electrical signals and their conduction along the arterial wall. The distance electrical phenomena conduct is primarily governed by gap junctions and membrane resistivity. In this study we determined whether changes in ion channel activity alter membrane resistivity, limiting electrical conduction. Middle cerebral arteries from Syrian hamsters were isolated, cannulated and studied under the standard conduction protocol. A focal KCl stimulus elicited a constrictor response that conducted robustly along the arterial wall with a decay constant of 0.484±0.036 μm/100μm vessel length. Manipulating the activity of large‐conductance Ca2+‐activated or voltage‐dependent K+ channels did not produce significant changes in conduction decay. Blocking and/or activating ATP‐sensitive K+ channels also failed to modify the conducted response. In contrast, Ba2+ blockade of inwardly‐rectifying K+ (KIR) channels augmented conduction decay (1.452±0.22 μm/100μm length), an effect attributed to the selective loss of negative slope conductance. In addition, experiments performed for the first time on human cerebral arteries displayed a similar increase in conduction decay in response to KIR inhibition. This study demonstrates that selective smooth muscle K+ conductances can tune electrical communication by retaining appropriate biophysical properties.