IU Indianapolis ScholarWorks :: Browsing by Author "Watson, Gordon A."

Browsing by Author "Watson, Gordon A."

Now showing 1 - 10 of 14

Analysis of Retrospective Versus Prospective Peer Review in a Multisite Academic Radiation Department
(Elsevier, 2023-08-09) Shiue, Kevin R.; Agrawal, Namita; Rhome, Ryan M.; DesRosiers, Colleen M.; Hutchins, Karen M.; Zellars, Richard C.; Watson, Gordon A.; Holmes, Jordan A.; Radiation Oncology, School of Medicine
Purpose: Our multisite academic radiation department reviewed our experience with transitioning from weekly primarily retrospective to daily primarily prospective peer review to improve plan quality and decrease the rate of plan revisions after treatment start. Methods and materials: This study was an institutional review board-approved prospective comparison of radiation treatment plan review outcomes of plans reviewed weekly (majority within 1 week after treatment start) versus plans reviewed daily (majority before treatment start, except brachytherapy, frame-based radiosurgery, and some emergent plans). Deviations were based on peer comments and considered major if plan revisions were recommended before the next fraction and minor if modifications were suggested but not required. Categorical variables were compared using χ2 distribution tests of independence; means were compared using independent t tests. Results: In all, 798 patients with 1124 plans were reviewed: 611 plans weekly and 513 plans daily. Overall, 76 deviations (6.8%) were noted. Rates of any deviation were increased in the daily era (8.6% vs 5.2%; P = .026), with higher rates of major deviations in the daily era (4.1% vs 1.6%; P = .012). Median working days between initial simulation and treatment was the same across eras (8 days). Deviations led to a plan revision at a higher rate in the daily era (84.1% vs 31.3%; P < .001). Conclusions: Daily prospective peer review is feasible in a multisite academic setting. Daily peer review with emphasis on prospective plan evaluation increased constructive plan feedback, plan revisions, and plan revisions being implemented before treatment start.
Analysis of Virtual Versus In-Person Prospective Peer Review Workflow in a Multisite Academic Radiation Oncology Department
(Elsevier, 2021-11) McClelland, Shearwood III; Amy Achiko, Flora; Bartlett, Gregory K.; Watson, Gordon A.; Holmes, Jordan A.; Rhome, Ryan M.; DesRosiers, Colleen M.; Hutchins, Karen M.; Shiue, Kevin; Agrawal, Namita; Radiation Oncology, School of Medicine
Purpose In radiation oncology, peer review is a process where subjective treatment planning decisions are assessed by those independent of the prescribing physician. Before March 2020, all peer review sessions occurred in person; however due to the COVID-19 pandemic, the peer-review workflow was transitioned from in-person to virtual. We sought to assess any differences between virtual versus in-person prospective peer review. Methods and Materials Patients scheduled to receive nonemergent nonprocedural radiation therapy (RT) were presented daily at prospective peer-review before the start of RT administration. Planning software was used, with critical evaluation of several variables including treatment intent, contour definition, treatment target coverage, and risk to critical structures. A deviation was defined as any suggested plan revision. Results In the study, 274 treatment plans evaluated in-person in 2017 to 2018 were compared with 195 plans evaluated virtually in 2021. There were significant differences in palliative intent (36% vs 22%; P = .002), but not in total time between simulation and the start of treatment (9.2 vs 10.0 days; P = .10). Overall deviations (8.0% in-person vs 2.6% virtual; P = .015) were significantly reduced in virtual peer review. Conclusions Prospective daily peer review of radiation oncology treatment plans can be performed virtually with similar timeliness of patient care compared with in-person peer review. A decrease in deviation rate in the virtual peer review setting will need to be further investigated to determine whether virtual workflow can be considered a standard of care.
Baseline Karnofsky performance status is independently predictive of death within 30 days of intracranial radiation therapy completion for metastatic disease
(Elsevier, 2020) McClelland, Shearwood, III.; Agrawal, Namita; Elbanna, May F.; Shiue, Kevin; Bartlett, Gregory K.; Lautenschlaeger, Tim; Zellars, Richard C.; Watson, Gordon A.; Ellsworth, Susannah G.; Radiation Oncology, School of Medicine
Introduction: For patients with brain metastases, palliative radiation therapy (RT) has long been a standard of care for improving quality of life and optimizing intracranial disease control. The duration of time between completion of palliative RT and patient death has rarely been evaluated. Methods: A compilation of two prospective institutional databases encompassing April 2015 through December 2018 was used to identify patients who received palliative intracranial radiation therapy. A multivariate logistic regression model characterized patients adjusting for age, sex, admission status (inpatient versus outpatient), Karnofsky Performance Status (KPS), and radiation therapy indication. Results: 136 consecutive patients received intracranial palliative radiation therapy. Patients with baseline KPS <70 (OR = 2.2; 95%CI = 1.6-3.1; p < 0.0001) were significantly more likely to die within 30 days of treatment. Intracranial palliative radiation therapy was most commonly delivered to provide local control (66% of patients) or alleviate neurologic symptoms (32% of patients), and was most commonly delivered via whole brain radiation therapy in 10 fractions to 30 Gy (38% of patients). Of the 42 patients who died within 30 days of RT, 31 (74%) received at least 10 fractions. Conclusions: Our findings indicate that baseline KPS <70 is independently predictive of death within 30 days of palliative intracranial RT, and that a large majority of patients who died within 30 days received at least 10 fractions. These results indicate that for poor performance status patients requiring palliative intracranial radiation, hypofractionated RT courses should be strongly considered.
Brainstem metastases treated with Gamma Knife stereotactic radiosurgery: the Indiana University Health experience
(Future Medicine:, 2018-01) Patel, Ajay; Mohammadi, Homan; Dong, Tuo; Shiue, Kevin Ren-Yeh; Frye, Douglas; Le, Yi; Ansari, Shaheryar; Watson, Gordon A.; Miller, James C.; Lautenschlaeger, Tim; Medicine, School of Medicine
Brainstem metastases offer a unique challenge in cancer treatment, yet stereotactic radiosurgery (SRS) has proven to be an effective modality in treating these tumors. This report discusses the clinical outcomes of patients with brainstem metastases treated at Indiana University with Gamma Knife (GK) radiosurgery from 2008 to 2016. 19 brainstem metastases from 14 patients who had follow-up brain imaging were identified. Median tumor volume was 0.04 cc (range: 0.01-2.0 cc). Median prescribed dose was 17.5 Gy to the 50% isodose line (range: 14-22 Gy). Median survival after GK SRS treatment to brainstem lesion was 17.2 months (range: 2.8-45.6 months). The experience at Indiana University confirms the safety and efficacy of range of GK SRS prescription doses (14-22 Gy) to brainstem metastases.
Development of a standardized method for radiation therapy contouring of the piriform cortex
(Old City Publishing, 2019) McClelland, Shearwood; Watson, Gordon A.; Radiation Oncology, School of Medicine
Discovery of increased number or interval growth of brain metastases on same-day GammaKnife™ planning MRI: Predicting factors and patient outcomes
(Old City Publishing, 2022) Mereniuk, Todd R.; Burney, Heather N.; Lautenschlaeger, Tim; Watson, Gordon A.; Rhome, Ryan M.; Radiation Oncology, School of Medicine
Purpose: To determine factors associated with increased risk of finding new and/or enlarged brain metastases (BM) on GammaKnife™ (GK) MRI and their impact on patient outcomes. Results: 43.9% of patients showed BM growth, 32.9% had additional brain metastases (aBM), and 18.1 % had both. Initial brain metastasis velocity (iBMV) was associated with finding aBM. Time between diagnostic MRI (dMRI) and GK MRI was associated with interval growth and each day increased this risk by 2%. Prior brain metastasectomy and greater time between either dMRI or latest extracranial RT and GK MRI predicted both aBM and BM growth. aBM and/or BM growth led to management change in 1.8% of cases and were not associated with OS or incidence of distant intracranial failure. Conclusions: Number of metastases seen on dMRI and iBMV predicted both aBM and/or BM growth, however, these factors did not significantly affect survival or incidence of distant intracranial failure.
Effects of Proton Center Closure on Pediatric Case Volume and Resident Education at an Academic Cancer Center
(Elsevier, 2018-03) Galle, James O.; Long, David E.; Lautenschlaeger, Tim; Zellars, Richard C.; Watson, Gordon A.; Ellsworth, Susannah G.; Radiation Oncology, School of Medicine
Purpose To analyze effects of closure of an academic proton treatment center (PTC) on pediatric case volume, distribution, and resident education. Methods and Materials This was a review of 412 consecutive pediatric (age ≤18 years) cases treated at a single institution from 2012 to 2016. Residents' Accreditation Council for Graduate Medical Education case logs for the same years were also analyzed. Characteristics of the patient population and resident case volumes before and after closure of the PTC are reported. Results Overall pediatric new starts declined by approximately 50%, from 35 to 70 per 6 months in 2012 to 2014 to 22 to 30 per 6 months in 2015 to 2016. Central nervous system (CNS) case volume declined sharply, from 121 patients treated in 2012 to 2015 to 18 patients in 2015 to 2016. In 2012 to 2014 our institution treated 36, 24, and 17 patients for medulloblastoma/intracranial primitive neuroectodermal tumor, ependymoma, and low-grade glioma, respectively, compared with 0, 1, and 1 patient(s) in 2015 to 2016. Forty-nine patients were treated with craniospinal radiation (CSI) from 2012 to 2014, whereas only 2 patients underwent CSI between 2015 and 2016. Hematologic malignancy patient volume and use of total body irradiation remained relatively stable. Patients treated when the PTC was open were significantly younger (9.1 vs 10.7 years, P=.010) and their radiation courses were longer (35.4 vs 20.9 days, P<.0001) than those treated after its closure. Resident case logs showed only a small decline in total pediatric cases, because the percentage of pediatric cases covered by residents increased after PTC closure; however, residents logged fewer CNS cases after PTC closure versus before. Conclusions Overall pediatric case volume decreased after PTC closure, as did the number of patients treated for potentially curable CNS tumors. Our findings raise important questions regarding resident training in pediatric radiation oncology as these cases become increasingly concentrated at specialized centers.
Nearly Half of Metastatic Brain Disease Patients Prescribed 10 Fractions of Whole-Brain Radiation Therapy Die Without Completing Treatment
(Elsevier, 2019) McClelland, Shearwood, III; Agrawal, Namita; Shiue, Kevin; Bartlett, Gregory K.; Zellars, Richard C.; Watson, Gordon A.; Ellsworth, Susannah G.; Radiation Oncology, School of Medicine
Predictors of linear accelerator versus Gamma Knife stereotactic radiosurgery use for brain metastases in the United States
(Oxford Academic, 2019-11) McClelland, Shearwood, III.; Degnin, Catherine; Chen, Yiyi; Watson, Gordon A.; Jaboin, Jerry J.; Radiation Oncology, School of Medicine
INTRODUCTION Stereotactic radiosurgery (SRS) for brain metastases is predominantly delivered via single-fraction Gamma Knife SRS (GKRS) or linear accelerator (LINAC) in 1–5 fractions. Predictors of SRS modality have been sparsely examined on a nationwide level. METHODS The 2010–2016 National Cancer Database identified brain metastases patients from non-small cell lung cancer throughout the United States (US) having undergone SRS. A multivariable logistic regression model characterized SRS receipt, adjusting for patient age, dose, geographic location of treatment, facility type, and distance from treatment facility. RESULTS A total of 1,760 patients received GKRS, while 1,064 patients received LINAC SRS. Treatment at non-academic facilities was associated with increased LINAC SRS receipt, most prominently in the Midwestern (OR= 6.23; p< 0.001), Northeastern (OR= 4.42; p< 0.001), and Southern US (OR= 1.96;p< 0.001). Administered doses of 18–19 Gy (OR= 1.42;p= 0.025), 20–21 Gy (OR= 1.82;p< 0.001), and 22–24 Gy (OR= 3.11;p< 0.001) were associated with increased LINAC SRS receipt, as was patient location within 20 miles of a radiation treatment facility (OR= 1.27;p= 0.007). CONCLUSIONS Despite Gamma Knife being more prominently used over LINAC for SRS, patients treated at non-academic facilities outside of the Western US were substantially more likely to receive LINAC over Gamma Knife. Patients located in the Midwest were 523% more likely, Northeast 342% more likely, and South 96% more likely to receive LINAC when treated at a non-academic facility. Increasing dose independently predicted LINAC over GKRS, indicating that smaller tumors – particularly those less than two centimeters (consistent with RTOG 90-05 recommendations) – are being treated with LINAC. Finally, patients residing in close proximity to a treatment center were 27% more likely to receive LINAC, likely indicative of the increased geographic accessibility of LINAC compared with GKRS. These findings should result in hypothesis-generating questions to further explore predictors of LINAC versus GKRS.
Radiation Induced Cerebral Microbleeds in Pediatric Patients with Brain Tumors Treated with Proton Radiotherapy
(Elsevier, 2018) Kralik, Stephen F.; Mereniuk, Todd R.; Grignon, Laurent; Shih, Chie-Schin; Ho, Chang Y.; Finke, Whitney; Coleman, Peter W.; Watson, Gordon A.; Buchsbaum, Jeffrey; Radiology and Imaging Sciences, School of Medicine
Purpose Proton beam radiotherapy (PBT) has been increasingly utilized to treat pediatric brain tumors, however, limited information exists regarding radiation induced cerebral microbleeds (CMBs) among these patients. The purpose was to evaluate the incidence, risk factors, and imaging appearance of CMBs in pediatric patients with brain tumors treated with PBT. Methods A retrospective study was performed on 100 pediatric patients with primary brain tumors treated with PBT. CMBs were diagnosed by examining serial MRIs including susceptibility-weighted imaging. Radiation therapy plans were analyzed to determine doses to individual CMBs. Clinical records were used to determine risk factors associated with the development of CMBs in these patients. Results The mean age at time of PBT was 8.1 years. The median follow-up duration was 57 months. The median time to development of CMBs was 8 months (mean 11 months; range 3-28 months). The percentage of patients with CMBs was 43%, 66%, 80%, 81%, 83%, and 81% at 1-year, 2-years, 3-years, 4-year, 5-years, and greater than 5 years from completion of proton radiotherapy. The majority (87%) of CMBs were found in areas of brain exposed to ≥ 30 Gy. Risk factors included maximum radiotherapy dose (P=0.001), percentage and volume of brain exposed to ≥ 30 Gy (P=0.0004; P=0.0005), and patient age at time of PBT (P=0.0004). Chemotherapy was not a significant risk factor (P=0.35). No CMBs required surgical intervention. Conclusion CMBs develop in a high percentage of pediatric patients with brain tumors treated with proton radiotherapy within the first few years following treatment. Significant risk factors for development of CMBs include younger age at time of PBT, higher maximum radiotherapy dose, and higher percentage and volume of brain exposed to ≥ 30 Gy. These findings demonstrate similarities with CMBs that develop in pediatric brain tumor patients treated with photon radiotherapy.

Browsing by Author "Watson, Gordon A."

Results Per Page

Sort Options