A Comparison Between the Rates of Radiation Oncologist and Urologist Consultations in Men Diagnosed With Prostate Cancer in Northern Ontario, Canada.

Purpose: Recommendations from Cancer Care Ontario stress the importance of multidisciplinary care from radiologists and urologists for prostate cancer treatment. The present study sought to examine what percentage of patients had a consultation with a radiation oncologist before undergoing a radical prostatectomy in Ontario, Canada, between 2010 and 2019. Methods and Materials: Administrative health care databases were used to analyze the number of consultations billed to the Ontario Health Insurance Plan from radiologists and urologists who treated men with a first prostate cancer diagnosis (n = 22,169). Results: In Ontario, 94.70% of Ontario Health Insurance Plan billings for patients with prostate cancer who had a prostatectomy within 1 year of a prostate cancer diagnosis were from urology, and 37.66% and 1.77% of billings were received from radiation oncology and medical oncology specialties, respectively. When sociodemographic variables were examined, having a lower neighborhood income (adjusted odds ratio [aOR], 0.69; confidence interval [CI], 0.62-0.76) and a rural residence (aOR, 0.72; CI, 0.65-0.79) were associated with lower odds of receiving a consultation from a radiation oncologist. When billings for consultations were examined geographically by region, Northeast Ontario (Local Health Integrated Network 13) had the lowest odds of receiving a radiation consultation compared with the rest of Ontario (aOR, 0.50; CI, 0.42-0.59). Conclusions: The results of this study show that differences in equitable access to multidisciplinary health care exist for men with a first prostate cancer diagnosis who reside in more northern and rural regions within Ontario, relative to the rest of the province. The reasons for these findings are likely multifactorial and may include factors such as patient treatment preference and distance/travel to receive treatment. However, as diagnosis year increased, so did the chances of receiving a radiation oncologist consultation, and this upward trend may reflect the implementation of Cancer Care Ontario guidelines.

Do Radiation Oncology Residents Have a Preferred Radiation Treatment Planning Review Format?

In an era of increasing virtual communication, we aimed to investigate current formats used by radiation oncology residents for reviewing radiation treatment plans with attendings, preferences for formats, and reasons contributing to preferences. Residents enrolled in Canadian radiation oncology programs received questionnaires examining training level, typical review formats, preferred format, and reasons for preference. Analysis excluded PGY-1s due to insufficient exposure. Fifty-two residents participated. National response rate was 55%. Overall, hybrid review was the most used format (77%). Virtual review was the most preferred format (44%). Preference for virtual review was most common among junior residents (57%), while in-person review was most preferred by senior residents (45.4%). Few residents typically use their preferred format (35%). Reasons for preference varied between groups in convenience (p < 0.01), interactivity (p < 0.01), and teaching quality (p = 0.04). The persistence of e-learning suggests that virtual treatment planning education will continue to some degree. Junior residents prefer virtual review, while a clearly preferred review format was less apparent among senior residents. Preferences are multifactorial, and the trends seen in reasons for preference between formats may reflect advantages inherent to each. Progress is still needed in optimizing treatment planning education, as suggested by few residents using their preferred format. Residents and staff should collectively decide which educational format for treatment planning best meets educational needs.

An investigation of the pH dependence of copper-substituted anthrax lethal factor and its mechanistic implications.

Anthrax lethal factor (LF) is a zinc-dependent endopeptidase involved in the cleavage of proteins critical to the maintenance of host signaling pathways during anthrax infections. Although zinc is typically regarded as the native metal ion in vivo, LF is highly tolerant to metal substitution, with its replacement by copper yielding an enzyme (CuLF) 4.5-fold more active than the native zinc protein (at pH 7). The current study demonstrates that by careful choice of the buffer, ionic strength, pH and substrate, the activity ratio of CuLF and native LF can be increased to >40-fold. Using a fluorogenic LF substrate, such optimized assay conditions can be exploited to detect LF concentrations as low as 2 pM. In contrast to the zinc form, CuLF was found to be inhibited by bromide and iodide ions, to be resistant to metal loss under acidic conditions, and to display a sharp pH dependence with significantly shifted alkaline limb towards more acidic conditions. The alkaline limb in the enzyme's pH profile is suggested to originate from changes in the protonation state of the metal-bound water molecule which serves as the nucleophile in the catalytic mechanism. Based on these observations and studies on other zinc proteases, a minimal mechanism for LF is proposed.