Therapeutic cannabis use by patients with cancer in Canada: A national survey of the experiences, opinions and information needs of Radiation Therapists.

PURPOSE: To understand the experiences, opinions and information needs of Canadian Radiation Therapists when caring for cancer patients who are taking cannabis for therapeutic purposes (CTP). METHODS: The study employed prospective data collection, via a single cross-sectional web-based questionnaire. After REB approval, the questionnaire was distributed electronically to all Radiation Therapists across Canada. The questionnaire was open for a one month accrual, with reminders sent at two and four weeks. The raw data was aggregated using standard descriptive statistics. The response differences between naturally occurring demographic cohorts was determined using inferential statistics. RESULTS: Two hundred and eighty two Therapists completed the questionnaire (25.6%), of which 19.1% reported being approached by patients to talk about cannabis more than once per month and 4.4% reported initiating a conversation with patients about cannabis. There were no differences between the provinces or catchment areas regarding how common or socially acceptable cannabis use by patients was. Confidence in discussing cannabis was strongly positively correlated with ratings of current knowledge (r² 0.77). Of the respondents, 99.9% believed that their radiation therapy training did not prepare them to support patients using cannabis. CONCLUSIONS: The data revealed that patients more frequently seek out guidance for CTP than Therapists initiate those discussions. This lack of Therapist willingness to begin cannabis conversations was associated with the low levels of knowledge. Almost all Therapists recognized the limitations of their knowledge and expressed interest in receiving further information about cannabis. The findings of this study strongly advocate for the development of educational tools to meet Therapists clinical needs.

Cannabis and Radiation Therapy: A Scoping Review of Human Clinical Trials.

INTRODUCTION: It is estimated that at least 20% of Canadian patients with cancer use cannabis to alleviate symptoms of their disease and/or cope with the side effects of their treatment. Most patients want to learn more about cannabis from their healthcare team, but most oncology professionals feel too uninformed to make recommendations. The purpose of this scoping review was to address this oncology professionals' knowledge gap, by summarizing the literature on evaluations of the benefits and harms of cannabis use before, during, or after radiation therapy (RT). METHODS AND MATERIALS: A literature search was performed in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews guidelines, using multiple electronic databases and combinations of key terms. To be included, studies must address the use of cannabis in patients undergoing RT. In vitro and in vivo evaluations, reviews, and editorials were excluded. Eligible full text manuscripts were then subjected to a formal risk of bias assessment using the Cochrane RoB 2.0 or ROBINS-I frameworks. RESULTS: A total of 48 records were identified, and 8 articles were included after vetting. These 8 studies suggest that the use of cannabinoids may calm anxious patients about to start RT, reduce nausea and vomiting consistent with the contemporary standard of care, reduce the symptoms of relapse for patients with glioma, and provide symptom relief >3 years after head and neck RT but not during or immediately. Six of these studies contained a high risk of bias (eg lack of randomization, poor blinding, and subjective outcome assessments). Most studies reported mild episodes of drowsiness and dry mouth with Δ9tetrahydrocannabinol, but substantial rates of dizziness, fatigue, and disorientation were also seen. It is important to note that these studies did not measure the impact of long-term cannabis consumption. CONCLUSIONS: The existing body of literature evaluating the use of cannabinoids by patients undergoing RT is very limited. Well-designed randomized controlled trials are urgently needed, which address the significant design flaws of previous studies and evaluate the impact of phytocannabinoids in patients undergoing RT.

Implementing Workshops to Improve Radiation Therapists' Knowledge and Attitudes about Sexual Health Issues in Cancer Patients.

OBJECTIVES: Although it is widely acknowledged that radiotherapy treatments can have a negative impact on a patient's sexual health, this aspect of side effect management is not commonly addressed by radiation therapists or by other cancer specialists. It is important for radiation therapists to recognize and address possible sexual health issues to provide a holistic approach to care. This quality-improvement project was designed to help radiation therapists discuss the sexual health needs of patients undergoing radiotherapy by improving their clinical knowledge, skills, and comfort level about the topic. METHODS: This study used a cross-sectional descriptive prequestionnaire/postquestionnaire design, in which data were collected from a nonrandom sample of radiation therapists at a single urban radiation therapy center. Participants attended two 90-minute sexual health education workshops specifically designed for radiation therapists and completed online preworkshop/postworkshop questionnaires. All questions were quantitative in nature. The survey consisted of multiple-choice, multiple-select, and five-point Likert-scale questions. Descriptive analysis was used for data analysis. RESULTS: The results of this improvement project indicated that participants had introductory-level knowledge about how cancer treatments can impact patients' sexual health. Although there is potential for some changes in the general knowledge levels of the participants after the initiative, two general workshops about the topic are not enough to have radiation therapists feel comfortable enough with the topic to change their clinical practice. CONCLUSION: This project identified that although radiation therapists acknowledge the importance of discussing sexual health concerns as part of delivering holistic health care, lack of knowledge and expertise with the topic is a main barrier to initiating conversations. To help prepare radiation therapists, education and training initiatives, which build on knowledge and offer opportunities to develop and apply practical skills in both simulated and real-life situations, should be created. This can help to increase confidence in the sexual health counseling provided, which may result in more radiation therapists frequently engaging in these important sexual health conversations.

Quantification of interobserver variability in image registration using cone beam CT for partial bladder radiotherapy-a comparison between lipiodol and bladder wall surface.

OBJECTIVE:: The use of lipiodol or bladder wall surface (BWS) for image guidance has improved the treatment quality for partial bladder irradiation. Currently, this procedure is manually performed by different users. This study assessed the interobserver variability of using image guidance for partial bladder irradiation. METHODS:: 7 observers were prospectively recruited to manually register 5 cone beam CTs (CBCT) from each of 20 bladder cancer patients with lipiodol injected for tumor demarcation. Lipiodol and BWS were used to register the CBCT to pre-treatment reference images, and displacement values in three directions were collected. Mean difference among observers and the 95% limit of agreement were calculated to measure interobserver variability. Margin required and the resultant treatment volume were compared between the surrogates. RESULTS:: A total of 4200 displacement values were collected for analysis. Lipiodol was superior to BWS, with a mean difference among observers of <2 mm and a 95% limit of agreement of <5 mm in all directions. Of the three directions, greatest variability was observed in the superior-inferior direction for both surrogates, hence requiring a larger margin than the other two directions. After applying the corresponding margin, the mean volume of BWS-planning target volume was calculated to be significantly larger than lipiodol-planning target volume (166 cm3vs 134 cm3, p < 0.05). CONCLUSIONS:: The use of lipiodol achieved a higher interobserver agreement than BWS. A larger margin in the superior-inferior direction is recommended due to greater interobserver variability observed in this direction for both surrogates. ADVANCES IN KNOWLEDGE:: The uncertainty associated with the image registration by multiple observers for bladder image-guided radiotherapy is quantified for two surrogates.

Impact of image registration surrogates on the planning target volume geometry for bladder radiation therapy.

PURPOSE: The use of Lipiodol and cone beam computed tomography (CT) has facilitated the generation of patient-specific planning target volumes (PTV) to reduce irradiation of normal tissue. However, injecting Lipiodol to demarcate the target volume is an invasive procedure. Center of bladder (COB) and bladder wall surface (BWS) encompassed by the clinical target volume (CTV) are proposed to be the alternative noninvasive surrogates. This study examines the impact of using these 3 surrogates for image registration on the resultant geometry of patient-specific PTVs. METHODS AND MATERIALS: Twenty bladder cancer patients who had Lipiodol injection before planning CT were included. Lipiodol, CTV, and bladder were delineated on the planning CT. In addition, CTVs were delineated on 5 cone beam CT scans from each patient. Cone beam CT scans were registered to planning CT using Lipiodol, COB, and BWS to generate Lipiodol-PTV, COB-PTV, and BWS-PTV. Using Lipiodol as the reference, the difference in the 2-dimensional/3-dimensional displacement values and the geometry of the resultant PTVs were quantified. RESULTS: A total of 1200 displacement values and 60 volumes were included for analysis. The overall median and standard deviation (SD) of the 3-dimensional displacement (mm) measured by Lipiodol, BWS, and COB are 25 (SD, 15), 24 (SD, 14), and 21 (SD, 15), respectively. Lipiodol-PTV has the smallest mean volume, followed by BWS-PTV and COB-PTV. BWS-PTV was more geometrically similar to Lipiodol-PTV when compared with COB-PTV. Six of 20 COB-PTVs who had CTV located at either the dome or the base of the bladder were larger than the corresponding Lipiodol-PTV by more than 20%. CONCLUSION: Lipiodol is the optimal image registration surrogate for partial bladder radiation therapy. However, for patients who are contraindicated for Lipiodol injection, BWS is the preferred noninvasive surrogate because the derived PTV has a smaller geometric variation from the Lipiodol-PTV when compared with COB, especially when the CTV was located at the dome or the base of the bladder.

A magnetic resonance imaging study of prostate deformation relative to implanted gold fiducial markers.

PURPOSE: To describe prostate deformation during radiotherapy and determine the margins required to account for prostate deformation after setup to intraprostatic fiducial markers (FM). METHODS AND MATERIALS: Twenty-five patients with T1c-T2c prostate cancer had three gold FMs implanted. The patients presented with a full bladder and empty rectum for two axial magnetic resonance imaging (MRI) scans using a gradient recalled echo (GRE) sequence capable of imaging the FMs. The MRIs were done at the time of radiotherapy (RT) planning and a randomly assigned fraction. A single observer contoured the prostate surfaces. They were entered into a finite element model and aligned using the centroid of the three FMs. RESULTS: During RT, the prostate volume decreased by 0.5%/fraction (p = 0.03) and the FMs in-migrated by 0.05 mm/fraction (p < 0.05). Prostate deformation was unrelated to differential bladder and bowel filling, but was related to a transurethral resection of the prostate (TURP) (p = 0.003). The standard deviation for systematic uncertainty of prostate surface contouring was 0.8 mm and for FM centroid localization was 0.4 mm. The standard deviation of random interfraction prostate deformation was 1.5 mm and for FM centroid variability was 1.1 mm. These uncertainties from prostate deformation can be incorporated into a margin recipe to determine the total margins required for RT. CONCLUSIONS: During RT, the prostate exhibited: volume decrease, deformation, and in-migration of FMs. Patients with TURPs were prone to prostate deformation.