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Purpose/Objectives To determine the utilization of and barriers to implementation of radiopharmaceutical therapy (RPT) amongst U.S. radiation oncologists. Materials/Methods An anonymous, voluntary 21-item survey directed towards attending radiation oncologists was distributed via social media platforms (Twitter, LinkedIn, Facebook, Student Doctor Network). Questions assessed practice characteristics, specific RPT prescribing patterns, RPT prescribing interest, and perceived barriers to RPT implementation. Non-parametric χ2 test was used for correlation statistics. Results Of the 142 respondents, 131 (92.3%) practiced in the U.S. and were included for this analysis. Respondents were well balanced in terms of practicing region, population size served, practice setting and years in practice. Forty-eight percent (n=63) reported prescribing at least one RPT. An additional 7% (n=8) participate in RPT administration without billing themselves. Among those that actively prescribed RPT, the mean cumulative cases per month was 4.2 (range: 1-5). The most commonly prescribed radionuclides were Radium-223 (40%; mean 2.8 cases/month), Iodine-131 (18%; mean 2.3 cases/month), Yttrium-90 (13%; mean 3.4 cases/month), “other” (8%), Samarium-153 (6%; mean 1.0 cases/month), Strontrium-89 and Phosphorous-32 (2% each; mean 1.8 and 0.4 cases/month respectively). Of those who answered “other”, Lutetium-177 dotatate was most commonly prescribed (8%). No significant (p Most radiation oncologists (56%, n=74) responded they would like to actively prescribe more RPT, while 27% (n=35) were indifferent and 17% (n=22) answered “no.” Perceived barriers to implementation were varied but broadly categorized into treatment infrastructure (44%, n=57), inter-specialty relations (41%, n=53), lack of training (23%, n=30), and financial considerations (16%, n=21). Conclusion Among surveyed U.S. radiation oncologists, a significant number reported prescribing at least one RPT. The majority expressed interest in prescribing additional RPT. Wide-ranging barriers to implementation exist, most commonly inter-specialty relations, treatment infrastructure, lack of training, and financial considerations.

PURPOSE/OBJECTIVE(S) To survey the utilization, interest in, and barriers to implementation of radiopharmaceuticals/unsealed sources amongst U.S. radiation oncologists. MATERIALS/METHODS An anonymous, voluntary survey directed towards attending radiation oncologists was distributed via social media platforms (Twitter, LinkedIn, SDN, Facebook). Questions assessed practice characteristics, radiopharmaceutical prescribing patterns (Iodine-131, Radium-223, Yttrium-90, Sumarium-153, Strontium-89, Phosphorous-32, "other"), prescribing interest level, and perceived barriers to implementation. Non-parametric χ2 test was used for correlation statistics. RESULTS Of the 120 respondents, 112 practiced in the U.S and were included for this analysis. Years of practice was broadly distributed with 30% (n = 34) of attendings in practice > 10 years, 21% (n = 23) 6-10 years, 25% (n = 28) 3-5 years, and 24% (n = 27) 0-2 years. Practice type included academic-main site amongst 39% (n = 44), academic-satellite in 18% (n = 20), and private practice/other in 43% (n = 48) of attendings. Forty-four percent (n = 49) of attendings served populations of > 500K, 22% (n = 25) 200-500K, 25% (n = 28) 100-200K, and 9% (n = 10) 0.05) association was noted between practice type, practice location, years of practice, or practice volume with utilization of any radiopharmaceuticals/unsealed sources. The majority (55%, n = 61) of attending radiation oncologists responded they would like to actively prescribe more radiopharmaceuticals/unsealed sources, while 30% (n = 31) were indifferent and 18% (n = 20) answered "no." Perceived barriers to implementation were varied but broadly categorized into treatment infrastructure (43%, n = 48), interspecialty relations (42%, n = 47), lack of training (21%, n = 24), and financial considerations (17%, n = 19). CONCLUSION Almost half of surveyed U.S. radiation oncologists reported prescribing at least one radiopharmaceuticals/unsealed source, of which Ra-223 was the most common. The majority expressed interest in prescribing additional radiopharmaceuticals/unsealed sources. Wide-ranging barriers to implementation exist, most commonly interspecialty relations, treatment infrastructure, lack of training, and financial considerations.

PURPOSE/OBJECTIVE(S) Cannabis use rates are increasing throughout the United States along with shifts in state-level policy. Patients with cancer use cannabis for a broad range of indications, but there is limited quality data to support many of these uses. To date, few studies have sought to understand cannabis use in populations of patients served by radiation oncology departments. MATERIALS/METHODS Standardized electronic medical record prompts were used by clinicians for cannabis history documentation for 1050 adult patients seen for initial consultation or follow-up between 10/2020 and 2/2021 at an academic radiation oncology department. Cannabis use data, including recency/frequency of use, indication, and mode of administration, were later gathered using the Michigan Radiation Oncology Analytics Resource (M-ROAR) under an IRB-approved protocol. Cannabis use characteristics were summarized, and logistic regression was used to explore associations between age and gender and recent cannabis use. RESULTS In total, 54 (5.1%) of 1050 unique patients declined to answer questions about cannabis use. Of the remaining 996 patients, 106 (10.6%) endorsed recent cannabis use (≤1 month ago), 71 (7.1%) noted remote use (> 1 month ago), and 819 (82.2%) denied history of cannabis use. The median age of those with recent cannabis use was 59.5 (IQR: 49.7-66.4) vs. 65.4 (IQR: 57.1-73.5) in all others. A multivariable logistic regression analysis revealed an association between age (OR 0.96; 95% CI: 0.95-0.97; P < 0.001) but not gender (male OR 1.24; 95% CI: 0.82-1.88; P = 0.310) and recent cannabis use. Patients noted pain (46.2%), anxiety (23.6%), insomnia (17.9%), "for the high" (17.0%), nausea (15.1%), poor appetite (14.2%), "to fight cancer" (4.7%), and depression (1.9%) as indications for use. The most common mode of administration was inhalation via smoking (47.2%), followed by oral (edibles, 36.8%), topical (15.1%), oral (drinks, 4.7%), vaping (3.8%), sublingual (1.0%), and rectal (1.0%). Most patients used cannabis daily (58.5%). Only 4 individuals (3.8%) noted use multiple times daily, while the remainder endorsed weekly (20.8%) or less than weekly (17.0%) use. CONCLUSION Approximately 10% of patients seen in a radiation oncology department reported recent cannabis use for a variety of reasons. These findings suggest a need for: 1) collection of cannabis use history in radiation oncology departments, 2) efforts to destigmatize cannabis use to facilitate frank discussions between patients and providers, 3) patient education about the fact that cannabis is not an evidence-based cancer treatment, 4) recommendation against inhaled forms of cannabis, which may carry risk of pulmonary toxicity, and 5) careful application of proven therapies to address symptoms when appropriate to provide alternatives to cannabis. Further research is needed to assess changes in cannabis use patterns over the course of cancer treatment and to evaluate risks and benefits of cannabis use in patients with cancer.

Multiple factors influence the risk of developing pneumonitis after radiation therapy (RT) for lung cancer, but few resources exist to guide clinicians in predicting risk in an individual patient treated with modern techniques. We analyzed toxicity data from a state-wide consortium to develop an integrated pneumonitis risk model.All patients (N = 1302) received conventionally fractionated RT for stage II-III non-small cell lung cancer between April 2012 and July 2019. Pneumonitis occurring within 6 months of treatment was graded by local practitioners and collected prospectively from 27 academic and community clinics participating in a state-wide quality consortium. Pneumonitis was modeled as either grade ≥2 (G2+) or grade ≥3 (G3+). Logistic regression models were fit to quantify univariable associations with dose and clinical factors, and stepwise Akaike information criterion-based modeling was used to build multivariable prediction models.The overall rate of pneumonitis of any grade in the 6 months following RT was 16% (208 cases). Seven percent of cases (n = 94) were G2+ and1% (n = 11) were G3+. Adjusting for incomplete follow-up, estimated rates for G2+ and G3+ were 14% and 2%, respectively. In univariate analyses, gEUD, V5, V10, V20, V30, and mean lung dose (MLD) were positively associated with G2+ pneumonitis risk, whereas current smoking status was associated with lower odds of pneumonitis. G2+ pneumonitis risk of ≥22% was independently predicted by MLD of ≥20 Gy, V20 of ≥35%, and V5 of ≥75%. In multivariate analyses, the lung V5 metric remained a significant predictor of G2+ pneumonitis, even when controlling for MLD, despite their close correlation. For G3+ pneumonitis, MLD and V20 were statistically significant predictors. Number of patient comorbidities was an independent predictor of G3+, but not G2+ pneumonitis.We present an analysis of pneumonitis risk after definitive RT for lung cancer using a large, prospective dataset. We incorporate comorbidity burden, smoking status, and dosimetric parameters in an integrated risk model. These data may guide clinicians in assessing pneumonitis risk in individual patients.

Purpose/objective(s) Guideline and clinical adoption of new radiotherapeutic approaches commonly requires 5-10 years of follow-up in randomized trials to ensure long-term safety. This is resource intensive and slows the pace of advancement. We hypothesized that the relative risk (RR) of radiation-induced gastrointestinal (GI) or genitourinary (GU) toxicity would remain similar or decrease overtime with long-term follow-up. Materials/methods PubMed and Embase were systematically searched for randomized trials evaluating changes in radiotherapy (RT; hypofractionation, dose escalation, change in field size) for localized prostate cancer published between 1970 and 2020. Yearly toxicity estimates were digitally extracted for GI and GU toxicity. Short- and long-term toxicity were defined as toxicity arising in years 1-3 and 5-10 post-RT, respectively. RR differences of toxicity between trial arms were calculated, and differences between short- and long-term relative risk measures of toxicity were compared using paired sample Wilcoxon signed-rank tests weighted by trial size. Results Median follow-up was 6 years (range 3-16) of the included 29 trials (n = 18,069 men). Of trials that reported risk group (67%), 90% of patients had intermediate and high-risk disease, and 57% of patients received ADT. There was no evidence of an increase in the RR of any grade of GI or GU toxicity with follow-up beyond 3 years. The mean RR point estimate of short- vs long-term GI and GU toxicity consistently decreased over time, which was represented by negative values for all grades. Mean differences (late RR - early RR) for grade 1, 2+ and 3+ GI toxicity were (-0.12, P Conclusion While toxicity events may continue to occur over time, the relative difference at later time points is similar or lower compared to early time points. Thus, our data does not support concerns for very late relative increases in radiation-induced toxicity. Physician reported toxicity assessed up to 3 years post-treatment is likely sufficient to establish safety following alternative radiotherapy dose/fractionation schedules and target volumes in prostate cancer.

Purpose Dose to normal lung has commonly been linked with radiation-induced lung toxicity (RILT) risk, but incorporating functional lung metrics in treatment planning may help further optimize dose delivery and reduce RILT incidence. The purpose of this study was to investigate the impact of the dose delivered to functional lung regions by analyzing perfusion (Q), ventilation (V), and combined V/Q single-photon-emission computed tomography (SPECT) dose-function metrics with regard to RILT risk in patients with non-small cell lung cancer (NSCLC) patients who received radiation therapy (RT). Methods and Materials SPECT images acquired from 88 patients with locally advanced NSCLC before undergoing conventionally fractionated RT were retrospectively analyzed. Dose was converted to the nominal dose equivalent per 2 Gy fraction, and SPECT intensities were normalized. Regional lung segments were defined, and the average dose delivered to each lung region was quantified. Three functional categorizations were defined to represent low-, normal-, and high-functioning lungs. The percent of functional lung category receiving ≥20 Gy and mean functional intensity receiving ≥20 Gy (iV20) were calculated. RILT was defined as grade 2+ radiation pneumonitis and/or clinical radiation fibrosis. A logistic regression was used to evaluate the association between dose-function metrics and risk of RILT. Results By analyzing V/Q normalized intensities and functional distributions across the population, a wide range in functional capability (especially in the ipsilateral lung) was observed in patients with NSCLC before RT. Through multivariable regression models, global lung average dose to the lower lung was found to be significantly associated with RILT, and Q and V iV20 were correlated with RILT when using ipsilateral lung metrics. Through a receiver operating characteristic analysis, combined V/Q low-function receiving ≥20 Gy (low-functioning V/Q20) in the ipsilateral lung was found to be the best predictor (area under the curce: 0.79) of RILT risk. Conclusions Irradiation of the inferior lung appears to be a locational sensitivity for RILT risk. The multivariable correlation between ipsilateral lung iV20 and RILT, as well as the association of low-functioning V/Q20 and RILT, suggest that irradiating low-functioning regions in the lung may lead to higher toxicity rates.