17 results on '"Alexander L. Chin"'
Search Results
2. Stereotactic Radiosurgery After Resection of Brain Metastases: Changing Patterns of Care in the United States
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Gordon Li, Erqi L. Pollom, Melanie Hayden Gephart, Scott G. Soltys, Alexander L. Chin, Seema Nagpal, and Navjot Sandhu
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Adult ,Male ,Pediatrics ,medicine.medical_specialty ,Adolescent ,medicine.medical_treatment ,Disease ,Radiosurgery ,Logistic regression ,Resection ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,Quality of life ,parasitic diseases ,Humans ,Medicine ,Aged ,Retrospective Studies ,Brain Neoplasms ,business.industry ,Middle Aged ,medicine.disease ,Combined Modality Therapy ,United States ,Radiation therapy ,Treatment Outcome ,030220 oncology & carcinogenesis ,Female ,Surgery ,Neurology (clinical) ,Cranial Irradiation ,business ,Neurocognitive ,030217 neurology & neurosurgery ,Brain metastasis - Abstract
Management of symptomatic brain metastases often includes surgical resection with postoperative radiotherapy. Postoperative whole-brain radiotherapy (WBRT) improves intracranial control but detrimentally impacts quality of life and neurocognition. We sought to characterize the use in the United States of postoperative stereotactic radiosurgery (SRS), an evolving standard-of-care associated with reduced cognitive effects.With the MarketScan Commercial Claims and Encounters Database from 2007 to 2015, we identified patients aged 18-65 years treated with resection of a brain metastasis followed by SRS or WBRT within 60 days of surgery. Logistic regression estimated associations between co-variables (treatment year, age, sex, geographic region, place of service, insurance type, disease histology, comorbidity score, and median area household income and educational attainment) and SRS receipt.Of 4007 patients included, 1506 (37.6%) received SRS and 2501 (62.4%) received WBRT. Postoperative SRS increased from 16.5% (2007-2008) to 56.8% (2014-2015). Patients residing in areas with a median household income or an educational attainment below 50th percentile were significantly less likely to receive SRS after controlling for treatment year and other demographic characteristics (P0.01). Factors associated with greater odds of receiving SRS included younger age, female sex, melanoma histology, Western region location, hospital-based facility, and high-deductible health plan enrollment (P0.05 for each).Postoperative SRS for brain metastases has increased from 2007 to 2015, with the majority of patients now receiving SRS over WBRT. Patients in areas of lower socioeconomic class were less likely to receive SRS, warranting further investigation of barriers to SRS adoption.
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- 2020
3. Deep Learning Based Identification and Segmentation of Lung Tumors on Computed Tomography Images
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P. Dong, Karl Bush, Michael F. Gensheimer, M.A.S.A. Hasan, Billy W. Loo, Charles Huang, Alexander L. Chin, S.S. Zaky, Neil Panjwani, Mehr Kashyap, Lei Xing, Lucas K. Vitzthum, and Maximilian Diehn
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Cancer Research ,Contouring ,medicine.medical_specialty ,Radiation ,business.industry ,Deep learning ,computer.software_genre ,Pearson product-moment correlation coefficient ,symbols.namesake ,Oncology ,Sørensen–Dice coefficient ,Voxel ,Test set ,symbols ,Medicine ,Radiology, Nuclear Medicine and imaging ,Segmentation ,Artificial intelligence ,Radiology ,business ,computer ,Radiation oncologist - Abstract
PURPOSE/OBJECTIVE(S) Rapid and accurate estimation of tumor burden in biomedical images is essential for precisely monitoring cancer progression and assessing therapeutic response. The ability to detect and segment tumors using an automated approach is a key part of this task. Despite recent advances from deep learning, lung tumor delineation remains challenging, particularly when the tumor bounding box is not provided to the model. We hypothesized that clinical radiation oncology contours could supply a large enough dataset of 3D tumor segmentations to enable more accurate models. We developed and validated a deep learning-based model to identify and segment primary and metastatic lung tumors on computed tomography (CT) images. MATERIALS/METHODS We curated a dataset consisting of CT images and clinical segmentations of 1,916 lung tumors in 1,504 patients who received radiation treatment for one or more primary or metastatic lung tumors. Segmentation quality was independently verified by a radiation oncologist using a custom web application. This dataset was used to train two 3D U-Net convolutional neural networks with varying model properties: one using high-resolution and small input volumes, and one using low-resolution and large input volumes. Models were ensembled together during validation. Performance was evaluated using an external held-out test set of CT images and segmentations from 59 patients with a single primary or metastatic lung tumor, treated at a separate clinical site. This test set consisted of 50 primary lung cancers and 9 metastases. To benchmark model performance against physicians, the test set was also contoured by two additional radiation oncologists. RESULTS Median tumor volume in the external test set was 80.48 cubic centimeters (interquartile range [IQR]: 14.40 to 177.65). The segmentations generated by the ensembled model produced a mean Dice coefficient of 0.62 (IQR: 0.47 to 0.85) on the test set. The sensitivity for detecting a tumor, as defined by correctly predicting at least one voxel within a ground truth tumor, was 93.2%, and the Dice coefficient for the scans with correctly identified lesions was 0.67 (IQR: 0.53 to 0.85). In comparison, the mean interobserver Dice coefficient for the three physicians on the test set was 0.76 (IQR: 0.70 to 0.84). We observed strong correlation between physician-determined tumor size and model-predicted tumor size (Pearson correlation, r = 0.69, P < 0.0001). CONCLUSION An end-to-end deep learning-based model was able to identify and segment lung tumors in a completely automated fashion, with near-expert level performance. Such models could soon be useful for clinical contouring and automatic quantification of tumor burden.
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- 2021
4. SBRT Treatment Planning Study for the First Clinical Biology-Guided Radiotherapy System
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Murat Surucu, D. Pham, Bin Han, Alexander L. Chin, Lei Xing, Michael F. Gensheimer, Dylan Y. Breitkreutz, E. Simiele, Daniel T. Chang, Nataliya Kovalchuk, Dante P. I. Capaldi, N. Ngo, and Lucas K. Vitzthum
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Cancer Research ,Radiation ,business.industry ,medicine.medical_treatment ,Significant difference ,Conformity index ,Radiation therapy ,Oncology ,Treatment plan ,Medicine ,Radiology, Nuclear Medicine and imaging ,Lung volumes ,Radiation treatment planning ,business ,Previously treated ,Dose rate ,Nuclear medicine - Abstract
PURPOSE/OBJECTIVE(S) The first clinical biology-guided radiation therapy (BgRT) system - RefleXion X1 - is installed and is being commissioned for clinical use at our institution. The system delivers 6MV-FFF beam via 50 firing positions at 850 cGy/min dose rate on 60 rpm rotating gantry with the couch advancing in 2.1 mm increments. Collimation is achieved through a binary multi-leaf collimator system composed of 64 (6.25 mm width at 850 cm SAD) leaves and 10mm or 20mm jaws. The purpose of this study was to compare the treatment plan quality and delivery efficiency for SBRT cases without PET-guidance. MATERIALS/METHODS Five lung cancer patients (50 Gy/4fx) with motion-inclusive PTV previously treated with VMAT SBRT were selected for this retrospective study. For each VMAT plan a corresponding plan was generated on the RefleXion treatment planning system (TPS) using our institutional planning constraints. VMAT SBRT plans used 1-2 partial arcs with 10MV-FFF energy and 2400 MU/min dose rate. RefleXion SBRT plans used all 50 firing positions and 1 cm jaw collimation. As plan normalization option does not yet exist in the RefleXion TPS, the plans were optimized to achieve PTV D95% coverage with 100% of prescription dose to the best of planner's ability. All clinically relevant metrics in this study, including plan PTV D95%, PTV D1%, 50% isodose volume (I50%), Conformity Index (CI), organs at risk constraints, and treatment time were analyzed and compared between VMAT and RefleXion plans using paired t-tests. RESULTS Clinically acceptable plans were obtained with both techniques. The average PTV volume was 14.1 ± 6.4cc. For VMAT and RefleXion plans, no statistically significant difference was observed in PTV D95%, PTV D1%, CI or I50%. Ipsilateral lung volume spared at 12.4 Gy (VS12.4) was slightly greater (31.6cc increase, P < 0.035) and skin Dmax was slightly lower (1.4 Gy decrease, P < 0.038) for RefleXion plans. Treatment beam-on time was significantly longer for RefleXion plans (23.4min increase, P < 0.0002). CONCLUSION RefleXion TPS provided comparable plan quality to lung SBRT VMAT plans. Treatment beam-on time is significantly longer for the RefleXion system.
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- 2021
5. Genomic Predictors of Recurrence Patterns in Localized Soft Tissue Sarcoma Treated With Radiation Therapy
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M. Devine, Lynn Million, Nam Bui, Everett J. Moding, Kristen N. Ganjoo, and Alexander L. Chin
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Leiomyosarcoma ,Oncology ,Cancer Research ,medicine.medical_specialty ,Radiation ,business.industry ,medicine.medical_treatment ,Soft tissue sarcoma ,Soft tissue ,medicine.disease ,Radiation therapy ,medicine.anatomical_structure ,Unresected ,Median follow-up ,Internal medicine ,Localized disease ,medicine ,Abdomen ,Radiology, Nuclear Medicine and imaging ,business - Abstract
Purpose/objective(s) Soft tissue sarcomas (STSs) are diverse mesenchymal tumors that are primarily managed with surgery. Radiation therapy (RT) is frequently added pre- or post-operatively for localized disease but uncommonly used as definitive treatment because the majority of unresected tumors progress with RT alone. Advances in next-generation sequencing have led to the widespread use of clinical genomic profiling, but the genetic determinants of radiation response in STSs are unknown. We hypothesized that integrating patient outcome data and clinical tumor mutation profiling could identify genomic predictors of recurrence patterns after RT for localized STS. Materials/methods We retrospectively identified 31 patients treated at our institution with definitive RT with or without surgery for localized STS who underwent tumor genomic profiling using a sequencing platform. For genes altered in at least 10% of patients, the associations between genetic alterations and local failure or distant metastasis were analyzed with univariable and multivariable competing risk regression adjusted for the competing risk of death. Age, maximum tumor diameter, tumor grade, and extent of resection were included as co-variables, and P values were adjusted for multiple hypothesis testing. Results Median follow up was 24 months, and the median RT dose was 50.4 Gy in 28 fractions. The most common histologies were leiomyosarcoma (n = 4) and myxofibrosarcoma (n = 4). The majority of tumors were located in the trunk and extremities (68%) with the remaining tumors originating in the head and neck (16%) or abdomen and pelvis (16%). 48% of patients underwent margin-negative resection, 36% had microscopically positive margins, and 16% were unresected or had gross residual disease following surgery. Median age was 58, median tumor size was 7.5 cm, and 65% of tumors were high grade. On univariable analysis, younger age (P = 0.02) and extent of resection (P = 0.0002) were significantly associated with local recurrence, and there was a trend towards association between higher grade and distant metastasis (P = 0.09). On univariable analysis, amplification of FRS2 in isolation or in combination with MDM2 and CDK4 was associated with a significantly increased risk of local recurrence (n = 4, HR 4.3), and genetic alterations in FBXO11 were associated with a significantly increased risk of distant metastasis (n = 4, HR 3.9). On multivariable analysis, FBXO11 alterations continued to predict for distant metastasis (HR 5.7, P = 0.0002), but there were no significant predictors of local recurrence. Conclusion Our results suggest that somatic tumor mutations may contribute to the risk of local recurrence and distant metastasis in patients treated with RT for localized STS. Additional analysis and validation in larger multi-institutional cohorts will be critical to identify molecular predictors of prognosis and patterns of recurrence.
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- 2021
6. Patterns of Care in Patients With Isolated Nodal Recurrence After Definitive Stereotactic Ablative Radiotherapy for Non-Small Cell Lung Cancer
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B. Lau, C. Yoo, Millie Das, Joel W. Neal, S. Shaheen, Heather A. Wakelee, R.B. Ko, Billy W. Loo, C. Say, D.J. Merriott, M. Devine, Alexander L. Chin, Maximilian Diehn, E. Yi, and Lucas K. Vitzthum
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Cancer Research ,medicine.medical_specialty ,Radiation ,business.industry ,medicine.medical_treatment ,Retrospective cohort study ,Combination chemotherapy ,medicine.disease ,SABR volatility model ,Radiation therapy ,Oncology ,medicine ,Radiology, Nuclear Medicine and imaging ,Cumulative incidence ,Progression-free survival ,Radiology ,Stage (cooking) ,Lung cancer ,business - Abstract
Purpose/Objective(s) Patients treated with stereotactic ablative radiotherapy (SABR) for early-stage non-small cell lung cancer (NSCLC) have high rates of local control but may be at increased risk of nodal recurrence compared to those who undergo surgical resection with more invasive nodal evaluation. The optimal treatment for patients with isolated nodal recurrence (INR) is unclear. The purpose of this study is to determine the rate of INR after SABR for early-stage NSCLC and describe patterns of care and treatment outcomes for patients that experience INR. Materials/Methods This retrospective cohort study included 342 patients with stage T1-3N0 NSCLC treated with definitive SABR. We evaluated the estimated rate of INR using the cumulative incidence function with death as a competing risk and compared baseline factors among patients who did or did not experience INR. Among patients that experienced INR, we describe patterns of treatment and outcomes including overall (OS) and progression free survival (PFS) from the time of nodal failure using the Kaplan-Meier method. OS and PFS outcomes were compared between treatment groups using the log-rank test. Results Of the 342 patients treated with SABR from 2003-2018, 34 developed INR and 19 developed any nodal recurrence. Patients were treated with definitive SABR for T1 (62.6%, n = 214), T2 (25.4%, n = 87) and T3 (12.0%, n = 41) NSCLC with a median BED10 of 87.5. The 3- and 5-year cumulative incidence of INR was 9.3 (95% CI 6.1 – 12.4) and 10.1 (6.8 –13.4) %, respectively. Pathologic nodal staging prior to SBRT was 9.1 and 13.3 % (P = 0.68) for patients who did or did not experience INR, respectively. The median number of involved nodes at the time of recurrence was one with a maximum of four. Among the 30 patients with a known treatment course after INR, patients were treated with RT alone (26.7 %, n = 8), chemotherapy and RT (CRT) (43.3 %, n = 13), chemotherapy alone (13.3%, n = 4) or observation (16.7%, n = 5). RT regimens included standard fractionation (38.0%, n = 8), hypofractionation (52.4%, n = 11) or SABR (9.5%, n = 2). The estimated two-year OS and PFS for patients experiencing INR were 48.0 (32.6 - 70.7) % and 27.6 (14.7 – 52.8) %, respectively. Treatment with CRT was associated with improved OS (2 year est: 91.7 vs 16.7 %, P Conclusion INR occurred in approximately 10% of patients treated for early-stage NSCLC with SABR. Treatment paradigms for post-SABR INR varied significantly at our institution and included combined chemotherapy and radiation, chemotherapy alone, SABR and hypofractionated RT. The highest rates of survival in patients with post-SABR INR were observed in those treated with combined chemotherapy and radiation.
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- 2021
7. Pulmonary Hemorrhage in Patients Treated With Thoracic Stereotactic Ablative Radiotherapy and Anti-Angiogenic Agents
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Maximilian Diehn, Heather A. Wakelee, B. Lau, Kavitha Ramchandran, R.B. Ko, Alexander L. Chin, S. Shaheen, Y. Wu, Millie Das, Billy W. Loo, Joel W. Neal, H.J. No, Lucas K. Vitzthum, and M. Devine
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Pulmonary and Respiratory Medicine ,Cancer Research ,medicine.medical_specialty ,Radiation ,Bevacizumab ,business.industry ,Sunitinib ,medicine.medical_treatment ,Urology ,Retrospective cohort study ,medicine.disease ,SABR volatility model ,Ramucirumab ,Pazopanib ,Radiation therapy ,Oncology ,medicine ,Radiology, Nuclear Medicine and imaging ,Pulmonary hemorrhage ,business ,medicine.drug - Abstract
Purpose/Objective(s) Hemoptysis is a rare but potentially fatal toxicity associated with thoracic stereotactic ablative radiotherapy (SABR). Prior studies have suggested that vascular endothelial growth factor inhibitors (VEGFI) may potentiate the risk for pulmonary hemorrhage in patients treated with SABR for centrally located lung tumors. To what degree the risk of toxicity varies by timing of therapies or tumor location is uncertain. The purpose of this study is to evaluate the combined toxicity of VEGFIs and SABR for peripheral, central, or ultra-central tumors. Materials/Methods We evaluated patients with primary or metastatic lung tumors treated with SABR between 2008 and 2018 at a single institution. Baseline patient, tumor and treatment characteristics were evaluated. Pulmonary bleeding events were graded using CTCAE version 5.0. Rates of a grade three or higher (G3+) or any ipsilateral pulmonary hemorrhage at three years were estimated using the Kaplan-Meier method. We compared rates of bleeding by tumor location, treatment with a VEGFI, sequence of therapy and VEGFI within 90 days of SABR using the log-rank test. Results This retrospective cohort study included a total of 925 pulmonary tumors treated with SABR in 691 patients. There were 44 patients treated with a VEGFI (bevacizumab, sorafenib, pazopanib, sunitinib or ramucirumab), with the majority receiving bevacizumab (n = 38, 86.3%). Among those treated with a VEGFI, the median interval between VEGFI therapy and SABR was 16 weeks, ranging from zero days to 3.7 years, with 15 (34.0%) patients treated within 90 days of SABR. Patients were treated with SABR to peripheral (738, 79.8%), central (137, 14.8%) and ultra-central (50, 5.4%) locations with a median BED10 of 87.5 Gy. Median follow-up was 32.2 months for the overall cohort and 46.4 months for VEGFI patients. The rate of G3+ hemorrhage was significantly higher in patients treated with a VEGFI (7.3 vs 0.8%, P or ≤ 90 days (12.0 vs 0.0%, P = 0.17). Similarly, there was no significant difference between rates of G3+ hemorrhage when VEGFI was given before (12.9%), after (8.3%), or before and after SABR (0.0%). Conclusion VEGFI therapy was associated with an increased rate of high-grade hemorrhage in patients undergoing SABR to pulmonary tumors. Rates of high-grade hemorrhage were increased with VEGFI for both central/ultra-central and peripheral tumors although the absolute rate was low for peripheral tumors. While limited by low sample size and event rate, there was no correlation observed between interval or sequence of VEGFI and SABR and rate of high-grade hemorrhage.
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- 2021
8. Outcomes of Chemoradiation and Trimodality Therapy Among Elderly Patients with Locally Advanced Esophageal Cancer
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M. Xiang, Alexander L. Chin, Neil Panjwani, Elham Rahimy, Daniel T. Chang, and Erqi L. Pollom
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Oncology ,Cancer Research ,medicine.medical_specialty ,Radiation ,business.industry ,Internal medicine ,medicine ,Locally advanced ,Radiology, Nuclear Medicine and imaging ,Esophageal cancer ,business ,medicine.disease - Published
- 2019
9. (P14) Cost Effectiveness of Radiation and Chemotherapy for High-Risk Low Grade Glioma
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Yushen Qian, Satoshi Maruyama, Haju Kim, Erqi L. Pollom, Kiran A. Kumar, Jeremy P. Harris, Alexander L. Chin, Allison Pitt, Eran Bendavid, Douglas K. Owens, Ben Y. Durkee, and Scott G. Soltys
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Cancer Research ,Radiation ,Oncology ,Radiology, Nuclear Medicine and imaging - Published
- 2018
10. The Impact of IMRT on Health Care Costs Among Elderly Patients with Anal Squamous Cell Carcinoma
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Alexander L. Chin, Albert C. Koong, Daniel T. Chang, and Erqi L. Pollom
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Oncology ,Cancer Research ,medicine.medical_specialty ,Radiation ,business.industry ,Internal medicine ,Health care ,Anal Squamous Cell Carcinoma ,Medicine ,Radiology, Nuclear Medicine and imaging ,business - Published
- 2017
11. Cost-Effectiveness of Radiation and Chemotherapy for High-Risk Low Grade Glioma
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Yushen Qian, Jeremy P. Harris, Alexander L. Chin, K.A. Kumar, Allison L. Pitt, Satoshi Maruyama, Haju Kim, Ben Y. Durkee, Erqi L. Pollom, Scott G. Soltys, Eran Bendavid, and Douglas K Owens
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Oncology ,Cancer Research ,medicine.medical_specialty ,Chemotherapy ,Radiation ,Cost effectiveness ,business.industry ,medicine.medical_treatment ,Internal medicine ,medicine ,Radiology, Nuclear Medicine and imaging ,Low-Grade Glioma ,business - Published
- 2017
12. Stereotactic Radiosurgery for Benign Neurogenic Spinal Tumors
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D.K. Fujimoto, Gordon Li, Steven D. Chang, Iris C. Gibbs, Scott G. Soltys, John R. Adler, Melanie Hayden Gephart, John K. Ratliff, Alexander L. Chin, Sean Sachdev, Victor Tse, Atman Desai, and Robert L. Dodd
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Cancer Research ,medicine.medical_specialty ,Radiation ,Oncology ,business.industry ,medicine.medical_treatment ,medicine ,Radiology, Nuclear Medicine and imaging ,Radiology ,business ,Radiosurgery - Published
- 2017
13. Newly Diagnosed Glioblastoma: Delay in Radiation Therapy Initiation Associated With Adverse Socioeconomic Factors and Worse Survival
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Scott G. Soltys, D.K. Fujimoto, Yushen Qian, Erqi L. Pollom, Jeremy P. Harris, Alexander L. Chin, and Suzanne Tharin
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Cancer Research ,Pediatrics ,medicine.medical_specialty ,Radiation ,business.industry ,medicine.medical_treatment ,Newly diagnosed ,medicine.disease ,Radiation therapy ,Oncology ,Medicine ,Radiology, Nuclear Medicine and imaging ,Medical emergency ,business ,Socioeconomic status ,Glioblastoma - Published
- 2017
14. (P064) Patterns of Care in Adjuvant Therapy for Resected Oral Cavity Squamous Cell Cancer in the Elderly
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Alexander L. Chin, C. Jillian Tsai, Erqi L. Pollom, and Nancy Y. Lee
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Oncology ,Patterns of care ,Cancer Research ,medicine.medical_specialty ,Radiation ,Squamous cell cancer ,business.industry ,Oral cavity ,Internal medicine ,medicine ,Adjuvant therapy ,Radiology, Nuclear Medicine and imaging ,business - Published
- 2017
15. Impact of Spleen and Thoracic Spine Irradiation on Acute Hematologic Toxicity During Chemoradiation for Esophageal Cancer
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R. Von Eyben, Sonya Aggarwal, Alexander L. Chin, Albert C. Koong, Daniel T. Chang, and Karl Bush
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Cancer Research ,medicine.medical_specialty ,Radiation ,Thoracic spine ,business.industry ,Spleen ,Hematologic toxicity ,Esophageal cancer ,medicine.disease ,Surgery ,medicine.anatomical_structure ,Oncology ,medicine ,Radiology, Nuclear Medicine and imaging ,business - Published
- 2016
16. Dosimetric Accuracy of Bulk Density Assignment on MRI for Head and Neck IMRT Treatment Planning
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Alexander L. Chin, Boon-Keng Kevin Teo, and Alexander Lin
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Cancer Research ,medicine.medical_specialty ,Radiation ,Oncology ,business.industry ,Medicine ,Radiology, Nuclear Medicine and imaging ,Medical physics ,Head and neck ,business ,Nuclear medicine ,Radiation treatment planning - Published
- 2013
17. 31 The Role of Gastrointestinal Mechanical Forces in the Regulation of Gut Enterochromaffin Cell Secretion and the Implications for Irritable Bowel Disease
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Zakiya-Luna Siddique, Roswitha Pfragner, Irvin M. Modlin, Bauer E. Sumpio, Ignat Drozdov, Bjorn I. Gustafsson, Mark Kidd, and Alexander L. Chin
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medicine.medical_specialty ,Hepatology ,business.industry ,Internal medicine ,Gastroenterology ,Enterochromaffin cell ,Medicine ,Secretion ,Irritable bowel disease ,business - Published
- 2009
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