A two-center experience: The impact of COVID-19 on two brachytherapy programs in Ontario - virtual care, service suspension and radiation therapy workflow.

INTRODUCTION: Most brachytherapy (BT) procedures require general anesthesia and are therefore considered aerosol generating medical procedures (AGMPs). The COVID-19 pandemic impacted BT as services were prioritized by balancing the harm associated with COVID-19 infection versus the effect of delay of potentially curative treatment. This article summarizes the impact of the pandemic on BT programs in two cancer centers in a Canadian province. METHODS: As part of a quality assurance project, a retrospective study was conducted for the first five months of the pandemic (March 1 to July 31, 2020). Chart review and COVID-19 related mitigation strategies were identified by BT Clinical Specialist Radiation Therapists (bCSRT) in each center using electronic medical records, departmental reports, policies and procedures. RESULTS: Impact included start of virtual care (VC), shortened fractionation, suspension of services and workflow changes.  Both centers implemented VC strategies to reduce clinic visits: "same-day size and treat" strategy for post-operative endometrial cancer patients and virtual patient education for all patients. BT services that were suspended were low-dose-rate and high-dose-rate (HDR) prostate treatments (Center 1), lung and esophagus HDR treatments (Center 2).  Workflow changes that affected staff and patients in both centers included COVID-19 screening and the use of personal protective equipment. The centers were marginally different in workflow adjustments for AGMP procedures.  Those considered high-risk AGMP and low-risk cancer were suspended temporarily with alternate treatment strategies sought for some patients. Others had temporizing treatment such as androgen deprivation therapy to facilitate oncological safe deferral of procedures. CONCLUSION: Both BT programs delivered treatment to most patients with minimal delays and cancellations, where feasible. Some of the pandemic workflow changes continued to the current state of the pandemic. Long-term follow-up is needed to assess the impact of COVID-19 and treatment interruptions on oncologic outcomes.

Stability of Intracavitary Applicator Placement for HDR Brachytherapy of Cervix Cancer.

INTRODUCTION/BACKGROUND: Cervical cancer is often treated with a combination of external beam radiation therapy and high-dose-rate intracavitary brachytherapy. An intrauterine ring and tandem applicator is used for intracavitary brachytherapy. The dose is prescribed to the high-risk clinical target volume. The goals of this study were to investigate the stability of intracavitary applicator placement during patient transfer and to evaluate the dosimetric impact of displacement. METHODS: Fourteen patients with cervical cancer were analyzed. Three sets of orthogonal fluoroscopic radiographs were obtained in the high-dose-rate suite after the insertion and before treatment: pre-computed tomography (CT) fluoroscopic radiograph with patient in the lithotomy position, pre-CT fluoroscopic radiograph with patient in the legs down position, and post-CT fluoroscopic radiograph with patient in the legs down position. Applicator position after CT was compared with the pre-CT radiographs to determine if the position changed during patient transfer. The displacement was measured in the anterior-posterior, medio-lateral, and superior-inferior directions, as well as the degree of pitch, roll, and yaw. To study the impact of applicator shifts on dose to organs at risk (OARs), the ring and tandem applicator was shifted virtually in the BrachyVision treatment planning system. The OARs studied included the small bowel, sigmoid colon, rectum, and bladder. Five millimeter shifts were made in the superior-inferior, medio-lateral, and anterior-posterior direction. Three degree rotations were made in the pitch, yaw, and roll directions. Applicator shifts were analyzed in only one direction at a time. The dosimetric impact on OARs was evaluated by comparing the original and shifted/rotated plans to dose-volume histogram-based criteria. RESULTS: The average displacements were 1.9 ± 0.5 mm laterally, 3.0 ± 0.6 mm longitudinally, and 9.5 ± 1.5 mm anterior-posterior. The average applicator rotation on the posterior-anterior radiograph was 1.0 ± 0.2° and 2.6 ± 0.6° on the lateral radiograph. Five millimeter anterior-posterior shifts had the greatest effect on dose to OARs. On average, 5 mm anterior shifts had the greatest effect on the small bowel dose, where there was a 13.7% (79.6 cGy) increase in D2cc. Five millimeter anterior shifts also affected bladder dose, with a 36.5% (141.1 cGy) increase in D2cc. Five millimeter POST shifts increased the rectal D2cc by 28.6% (168.7 cGy). Other directional shifts had negligible effects on dose. The largest effect on OAR dose arising from rotations was to the sigmoid colon, when the applicator rotated in the POST pitch direction. As a result, the dose increased by 4.7% (7.6 cGy). All other rotations had minimal impact on OAR doses. CONCLUSION: Patient transfer resulted in applicator shifts and rotations that had a measurable effect on dose to OARs. The displacements were the result of either a direct shift or rotation of the applicator. Additional tracking of these shifts and rotations may clarify the sources of these unwanted motions and suggest possible mitigation strategies.

Pain Palliation Using Hypofractionated Radiotherapy for Unresectable Pancreatic Cancer.

BACKGROUND: Pain is a common symptom for patients with pancreatic cancer and is often treated using palliative radiation therapy. Standard palliative dose regimes typically consist of 2000 cGy to 3000 cGy in 5 to 10 fractions (fx). With the recent advancements in radiation dosimetric planning and delivery, the Juravinski Cancer Centre in Hamilton, Ontario, offers a hypofractionated dose of 2500 cGy in 5 fx for the improvement of pain and tumour control in selected pancreatic cancer patients. This project reviews the safety and efficacy of this prescription. METHODS: A retrospective analysis of 24 patients diagnosed with unresectable pancreatic cancer was conducted. Patient data were collected using in-house medical record systems including MOSAIQ, Meditech, and Centricity. Nonparametric data analysis tests were conducted using Minitab17. RESULTS: Nineteen of 24 patients (79%) reported a decrease in pain levels following radiation and 13 of 18 (72%) showed good local control of the tumour on a follow-up CT scan. Around 30% of patients reported nausea and vomiting and fatigue. Only 13% reported diarrhea and 8% reported constipation. Twenty-one percent reported pain flares. All patients were able to finish the entire treatment without pauses or delays. CONCLUSION: A palliative radiotherapy dose regime of 2500 cGy/5 fx demonstrates a potential for the effective control of pain with limited acute toxicities in patients with unresectable pancreatic cancer. This study aims to indicate the need for further prospective research comparing this regime to other standard treatments in order to determine which is most beneficial for the patient.

Prospective comparison of rectal dose reduction during intracavitary brachytherapy for cervical cancer using three rectal retraction techniques.

PURPOSE: To compare three rectal retraction methods on dose to organs at risk, focusing on rectal dose, in cervix cancer patients treated with high-dose-rate intracavitary brachytherapy. METHODS AND MATERIALS: A prospective study was conducted on patients with cervical carcinoma treated with chemoradiotherapy, including external beam radiation and four fractions of high-dose-rate intracavitary brachytherapy prescribed to Point A using a ring and tandem applicator under conscious sedation. Rectal retraction methods included: a rectal retractor blade (RR), vaginal gauze packing (VP), and a tandem Foley balloon (FB). All three methods were used in all patients. The RR was used first, and the following applications were randomly assigned to VP or FB. CT planning was used to calculate D2cc for rectum, sigmoid, small bowel, and bladder. The Wilcoxon signed rank test was used to determine if the median dose differences between methods were statistically significant. RESULTS: In these 11 patients, median dose (min, max) in cGy to the rectum using RR, FB, and VP was 131 (102, 165), 199 (124, 243), and 218 (149, 299), respectively. The RR demonstrated lower median intrapatient doses to rectum compared with FB and VP (-55 cGy; p = 0.014 and -76 cGy; p = 0.004, respectively). The RR also resulted in lower sigmoid doses. No differences in dose were observed between the VP and FB methods. CONCLUSION: The rectal retractor significantly reduced the dose to rectum and sigmoid compared with FP and VP. In patients treated under conscious sedation, the RR method provides the best rectal sparing. There were no significant differences in dose observed between the FB and VP techniques.

Assessing patient characteristics and radiation-induced non-targeted effects in vivo for high dose-rate (HDR) brachytherapy.

PURPOSE: To test whether blood, urine, and tissue based colony-forming assays are a useful clinical detection tool for assessing fractionated treatment responses and non-targeted radiation effects in bystander cells. MATERIALS AND METHODS: To assess patients' responses to radiation treatments, blood serum, urine, and an esophagus explant-based in vivo colony-forming assay were used from oesophageal carcinoma patients. These patients underwent three fractions of high dose rate (HDR) intraluminal brachytherapy (ILBT). RESULTS: Human keratinocyte reporters exposed to blood sera taken after the third fraction of brachytherapy had a significant increase in cloning efficiency compared to baseline samples (p < 0.001). Such results may suggest an induced radioresistance response in bystander cells. The data also revealed a clear inverse dose-rate effect during late treatment fractions for the blood sera data only. Patient characteristics such as gender had no statistically significant effect (p > 0.05). Large variability was observed among the patients' tissue samples, these colony-forming assays showed no significant changes throughout fractionated brachytherapy (p > 0.05). CONCLUSION: Large inter-patient variability was found in the urine and tissue based assays, so these techniques were discontinued. However, the simple blood-based assay had much less variability. This technique may have future applications as a biological dosimeter to predict treatment outcome and assess non-targeted radiation effects.

A prospective analysis of high-dose-rate endobronchial brachytherapy in the palliation of obstructive symptoms in lung cancer patients: A single-institution experience.

PURPOSE: Obstructive symptoms that affect quality of life (QOL) are commonly caused by endobronchial disease in many patients with locally advanced, inoperable lung cancer. High-dose-rate endobronchial brachytherapy (HDREBBT) has been used to palliate these symptoms, yet its role is not well defined in the literature. METHODS AND MATERIALS: Ninety-eight patients with locally advanced, inoperable lung cancer received HDREBBT. They were prospectively followed for survival, QOL, and toxicity endpoints. QOL measures were captured using the Quality of Life Questionnaire-Lung Cancer 30 and -Lung Cancer 13. RESULTS: At 1-year follow-up, no significant toxicities were seen. Overall survival was 13.4% at 12 months (mean 192 days). Performance status, additional treatment after HDREBBT and treatment intent affected overall survival on univariate analysis (p < 0.05). Mean hemoptysis-free survival for all patients was 232.3 days, cough-free survival was 140.3 days, and dyspnea-free survival was 173.5 days. There was no impact of any treatment- or patient-related factors of these outcomes on multivariate analysis, including additional treatment modalities and HDREBBT dose. CONCLUSIONS: HDREBBT is a safe and effective way to palliate endobronchial symptoms. Additional external-beam radiation therapy, chemotherapy, or chemoradiation after HDREBBT improves survival, but does not affect QOL measures.

Endotracheal brachytherapy alone: An effective palliative treatment for tracheal tumors.

BACKGROUND: Tracheal tumors are rare. They are usually unresectable and treated primarily with external beam radiation. The use of palliative endotracheal brachytherapy (ETBT) alone in treating patients with tracheal tumors has not been reported. METHODS: Using a prospective database, demographic, treatment, and outcome data of patients with tracheal tumors treated palliatively with ETBT from 2006 to 2014 were analyzed. Tumor and symptom responses were evaluated based on response evaluation criteria in solid tumors criteria. Survival, in-field disease control, symptom response, and duration of symptom responses were evaluated using descriptive analyses. RESULTS: Sixteen ETBT (median, 2) treatments were delivered to 8 patients. Median age was 63.4 years old. Common symptoms were hemoptysis, cough, and dyspnea. Tracheal lengths of 3.5-11 cm were treated with 5-7 Gy/fraction, using 1-3 fractions. The mean overall survival was 5 months and symptom-free survival was 6.8 months, respectively. After ETBT, 88% of patients experienced symptomatic improvement (hemoptysis [n = 3/3], cough [n = 6/7], and dyspnea [n = 4/4]). One patient developed Grade 1 stenosis that did not require intervention. CONCLUSIONS: This is among the largest series of tracheal tumors treated palliatively with ETBT alone. ETBT provided effective palliation with symptom improvement and minimal toxicity.