Browsing by Author "Kirkpatrick, John P"
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Item Open Access Adjuvant Radiation in Older Patients With Glioblastoma: A Retrospective Single Institution Analysis.(Frontiers in oncology, 2021-01) Lee, Jessica W; Kirkpatrick, John P; McSherry, Frances; Herndon, James E; Lipp, Eric S; Desjardins, Annick; Randazzo, Dina M; Friedman, Henry S; Ashley, David M; Peters, Katherine B; Johnson, Margaret OObjectives
Standard 6-week and hypofractionated 3-week courses of adjuvant radiation therapy (RT) are both options for older patients with glioblastoma (GBM), but deciding the optimal regimen can be challenging. This analysis explores clinical factors associated with selection of RT course, completion of RT, and outcomes following RT.Materials and methods
This IRB-approved retrospective analysis identified patients ≥70 years old with GBM who initiated adjuvant RT at our institution between 2004 and 2016. We identified factors associated with standard or hypofractionated RT using the Cochran-Armitage trend test, estimated time-to-event endpoints using the Kaplan-Meier method, and found predictors of overall survival (OS) using Cox proportional hazards models.Results
Sixty-two patients with a median age of 74 (range 70-90) initiated adjuvant RT, with 43 (69%) receiving standard RT and 19 (31%) receiving hypofractionated RT. Selection of short-course RT was associated with older age (p = 0.04) and poor KPS (p = 0.03). Eight (13%) patients did not complete RT, primarily for hospice care due to worsening symptoms. After a median follow-up of 37 months, median OS was 12.3 months (95% CI 9.0-15.1). Increased age (p < 0.05), poor KPS (p < 0.0001), lack of MGMT methylation (p < 0.05), and lack of RT completion (p < 0.0001) were associated with worse OS on multivariate analysis. In this small cohort, GTV size and receipt of standard or hypofractionated RT were not associated with OS.Conclusions
In this cohort of older patients with GBM, age and KPS was associated with selection of short-course or standard RT. These regimens had similar OS, though a subset of patients experienced worsening symptoms during RT and discontinued treatment. Further investigation into predictors of RT completion and survival may help guide adjuvant therapies and supportive care for older patients.Item Open Access An investigation of machine learning methods in delta-radiomics feature analysis.(PloS one, 2019-01) Chang, Yushi; Lafata, Kyle; Sun, Wenzheng; Wang, Chunhao; Chang, Zheng; Kirkpatrick, John P; Yin, Fang-FangPURPOSE:This study aimed to investigate the effectiveness of using delta-radiomics to predict overall survival (OS) for patients with recurrent malignant gliomas treated by concurrent stereotactic radiosurgery and bevacizumab, and to investigate the effectiveness of machine learning methods for delta-radiomics feature selection and building classification models. METHODS:The pre-treatment, one-week post-treatment, and two-month post-treatment T1 and T2 fluid-attenuated inversion recovery (FLAIR) MRI were acquired. 61 radiomic features (intensity histogram-based, morphological, and texture features) were extracted from the gross tumor volume in each image. Delta-radiomics were calculated between the pre-treatment and post-treatment features. Univariate Cox regression and 3 multivariate machine learning methods (L1-regularized logistic regression [L1-LR], random forest [RF] or neural networks [NN]) were used to select a reduced number of features, and 7 machine learning methods (L1-LR, L2-LR, RF, NN, kernel support vector machine [KSVM], linear support vector machine [LSVM], or naïve bayes [NB]) was used to build classification models for predicting OS. The performances of the total 21 model combinations built based on single-time-point radiomics (pre-treatment, one-week post-treatment, and two-month post-treatment) and delta-radiomics were evaluated by the area under the receiver operating characteristic curve (AUC). RESULTS:For a small cohort of 12 patients, delta-radiomics resulted in significantly higher AUC than pre-treatment radiomics (p-value<0.01). One-week/two-month delta-features resulted in significantly higher AUC (p-value<0.01) than the one-week/two-month post-treatment features, respectively. 18/21 model combinations were with higher AUC from one-week delta-features than two-month delta-features. With one-week delta-features, RF feature selector + KSVM classifier and RF feature selector + NN classifier showed the highest AUC of 0.889. CONCLUSIONS:The results indicated that delta-features could potentially provide better treatment assessment than single-time-point features. The treatment assessment is substantially affected by the time point for computing the delta-features and the combination of machine learning methods for feature selection and classification.Item Open Access Hippocampal Avoidance in Multitarget Radiosurgery.(Cureus, 2021-06-02) Gude, Zachary; Adamson, Justus; Kirkpatrick, John P; Giles, WilliamBrain metastases are a common complication for patients diagnosed with cancer. As stereotactic radiosurgery (SRS) becomes a more prevalent treatment option for patients with many brain metastases, further research is required to better characterize the ability of SRS to treat large numbers of metastases (≥4) and the impact on normal brain tissue and, ultimately, neurocognition and quality of life (QOL). This study serves first as an evaluation of the feasibility of hippocampal avoidance for SRS patients, specifically receiving single-isocenter multitarget treatments (SIMT) planned with volumetric modulated arc therapy (VMAT). Second, this study analyzes the effects of standard-definition (SD) multileaf collimators (MLCs) (5 mm width) on plan quality and hippocampal avoidance. The 40 patients enrolled in this Institutional Review Board (IRB)-approved study had between four and 10 brain metastases and were treated with SIMT using VMAT. From the initial 40 patients, eight hippocampi across seven patients had hippocampal doses exceeding the maximum biologically effective dose (BED) constraint given by RTOG 0933. With the addition of upper constraints in the optimization objectives and one arc angle adjustment in one patient plan, four out of seven patient plans were able to meet the maximum hippocampal BED constraint, avoiding five out of eight total hippocampi at risk. High-definition (HD) MLCs allowed for an average decrease of 29% ± 23% (p = 0.007) in the maximum BED delivered to all eight hippocampi at risk. The ability to meet dose constraints depended on the distance between the hippocampus and the nearest planning target volume (PTV). Meeting the maximum hippocampal BED constraint in re-optimized plans was equally likely with the use of SD-MLCs (five out of eight hippocampi at risk were avoided) but resulted in increased dose to normal tissue volumes (23.67% ± 16.3% increase in V50%[cc] of normal brain tissue, i.e., brain volume subtracted by the total PTV) when compared to the HD-MLC re-optimized plans. Comparing the effects of SD-MLCs on plans not optimized for hippocampal avoidance resulted in increases of 48.2% ± 32.2% (p = 0.0056), 31.5% ± 16.3% (p = 0.024), and 16.7% ± 8.5% (p = 0.022) in V20%[cc], V50%[cc], and V75%[cc], respectively, compared to the use of HD-MLCs. The conformity index changed significantly neither when plans were optimized for hippocampal avoidance nor when SD-MLC leaves were used for treatment. In plans not optimized for hippocampal avoidance, mean hippocampal dose increased with the use of SD-MLCs by 38.0% ± 37.5% (p = 0.01). However, the use of SD-MLCs did not result in an increased number of hippocampi at risk.Item Open Access Impact of collimator leaf width and treatment technique on stereotactic radiosurgery and radiotherapy plans for intra- and extracranial lesions.(Radiation oncology (London, England), 2009-01-21) Wu, Q Jackie; Wang, Zhiheng; Kirkpatrick, John P; Chang, Zheng; Meyer, Jeffrey J; Lu, Mei; Huntzinger, Calvin; Yin, Fang-FangBACKGROUND: This study evaluated the dosimetric impact of various treatment techniques as well as collimator leaf width (2.5 vs 5 mm) for three groups of tumors -- spine tumors, brain tumors abutting the brainstem, and liver tumors. These lesions often present challenges in maximizing dose to target volumes without exceeding critical organ tolerance. Specifically, this study evaluated the dosimetric benefits of various techniques and collimator leaf sizes as a function of lesion size and shape. METHODS: Fifteen cases (5 for each site) were studied retrospectively. All lesions either abutted or were an integral part of critical structures (brainstem, liver or spinal cord). For brain and liver lesions, treatment plans using a 3D-conformal static technique (3D), dynamic conformal arcs (DARC) or intensity modulation (IMRT) were designed with a conventional linear accelerator with standard 5 mm leaf width multi-leaf collimator, and a linear accelerator dedicated for radiosurgery and hypofractionated therapy with a 2.5 mm leaf width collimator. For the concave spine lesions, intensity modulation was required to provide adequate conformality; hence, only IMRT plans were evaluated using either the standard or small leaf-width collimators.A total of 70 treatment plans were generated and each plan was individually optimized according to the technique employed. The Generalized Estimating Equation (GEE) was used to separate the impact of treatment technique from the MLC system on plan outcome, and t-tests were performed to evaluate statistical differences in target coverage and organ sparing between plans. RESULTS: The lesions ranged in size from 2.6 to 12.5 cc, 17.5 to 153 cc, and 20.9 to 87.7 cc for the brain, liver, and spine groups, respectively. As a group, brain lesions were smaller than spine and liver lesions. While brain and liver lesions were primarily ellipsoidal, spine lesions were more complex in shape, as they were all concave. Therefore, the brain and the liver groups were compared for volume effect, and the liver and spine groups were compared for shape. For the brain and liver groups, both the radiosurgery MLC and the IMRT technique contributed to the dose sparing of organs-at-risk(OARs), as dose in the high-dose regions of these OARs was reduced up to 15%, compared to the non-IMRT techniques employing a 5 mm leaf-width collimator. Also, the dose reduction contributed by the fine leaf-width MLC decreased, as dose savings at all levels diminished from 4 - 11% for the brain group to 1 - 5% for the liver group, as the target structures decreased in volume. The fine leaf-width collimator significantly improved spinal cord sparing, with dose reductions of 14 - 19% in high to middle dose regions, compared to the 5 mm leaf width collimator. CONCLUSION: The fine leaf-width MLC in combination with the IMRT technique can yield dosimetric benefits in radiosurgery and hypofractionated radiotherapy. Treatment of small lesions in cases involving complex target/OAR geometry will especially benefit from use of a fine leaf-width MLC and the use of IMRT.Item Open Access Primary brain tumor patients admitted to a US intensive care unit: a descriptive analysis.(CNS oncology, 2021-09-21) Kang, Jennifer H; Swisher, Christa B; Buckley, Evan D; Herndon, James E; Lipp, Eric S; Kirkpatrick, John P; Desjardins, Annick; Friedman, Henry S; Johnson, Margaret O; Randazzo, Dina M; Ashley, David M; Peters, Katherine BPurpose: To describe our population of primary brain tumor (PBT) patients, a subgroup of cancer patients whose intensive care unit (ICU) outcomes are understudied. Methods: Retrospective analysis of PBT patients admitted to an ICU between 2013 to 2018 for an unplanned need. Using descriptive analyses, we characterized our population and their outcomes. Results: Fifty-nine PBT patients were analyzed. ICU mortality was 19% (11/59). The most common indication for admission was seizures (n = 16, 27%). Conclusion: Our ICU mortality of PBT patients was comparable to other solid tumor patients and the general ICU population and better than patients with hematological malignancies. Further study of a larger population would inform guidelines for triaging PBT patients who would most benefit from ICU-level care.Item Open Access The role of chemotherapy in the treatment of central neurocytoma.(CNS oncology, 2019-11-05) Johnson, Margaret O; Kirkpatrick, John P; Patel, Mallika P; Desjardins, Annick; Randazzo, Dina M; Friedman, Henry S; Ashley, David M; Peters, Katherine BAim: Central neurocytoma (CN) is a rare WHO grade II central nervous system (CNS) tumor. This is an update on chemotherapeutic agents used in its treatment. Patients & methods: An institutional review board-approved, chart review of patients seen at our institution resulted in a single case treated with chemotherapy and is herein included. We proceeded with a comprehensive literature review. Results: We identified 18 citations, representing 39 cases of adult and pediatric CN treated with chemotherapy. With the addition of our single case, the total number of recurrent CN patients treated with temozolomide (TMZ) is nine. Conclusion: There exists marked heterogeneity in chemotherapy used to treat CN. TMZ is incorporated into treatment regimens in the setting of tumor recurrence: its role merits further study.