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Dive into the research topics where Usama Mahmood is active.

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Featured researches published by Usama Mahmood.


Laryngoscope | 2005

In Vivo Optical Coherence Tomography of the Human Larynx: Normative and Benign Pathology in 82 Patients

Brian J. F. Wong; Ryan P. Jackson; Shuguang Guo; James M. Ridgway; Usama Mahmood; Jianping Su; Terry Y. Shibuya; Roger L. Crumley; Mai Gu; William B. Armstrong; Zhongping Chen

Objectives: Optical coherence tomography (OCT) is an emerging imaging modality that combines low‐coherence light with interferometry to produce cross‐sectional images of tissue with resolution about 10 μm. Patients undergoing surgical head and neck endoscopy were examined using a fiberoptic OCT imaging probe to study and characterize microstructural anatomy and features of the larynx and benign laryngeal pathology in vivo.


Journal of Clinical Oncology | 2014

Disparities in Stage at Diagnosis, Treatment, and Survival in Nonelderly Adult Patients With Cancer According to Insurance Status

Gary V. Walker; Stephen R. Grant; B. Ashleigh Guadagnolo; Karen E. Hoffman; Benjamin D. Smith; Matthew Koshy; Pamela K. Allen; Usama Mahmood

PURPOSE The purpose of this study was to determine the association of insurance status with disease stage at presentation, treatment, and survival among the top 10 most deadly cancers using the SEER database. PATIENTS AND METHODS A total of 473,722 patients age 18 to 64 years who were diagnosed with one of the 10 most deadly cancers in the SEER database from 2007 to 2010 were analyzed. A Cox proportional hazards model was used for multivariable analyses to assess the effect of patient and tumor characteristics on cause-specific death. RESULTS Overall, patients with non-Medicaid insurance were less likely to present with distant disease (16.9%) than those with Medicaid coverage (29.1%) or without insurance coverage (34.7%; P < .001). Patients with non-Medicaid insurance were more likely to receive cancer-directed surgery and/or radiation therapy (79.6%) compared with those with Medicaid coverage (67.9%) or without insurance coverage (62.1%; P < .001). In a Cox regression that adjusted for age, race, sex, marital status, residence, percent of county below federal poverty level, site, stage, and receipt of cancer-directed surgery and/or radiation therapy, patients were more likely to die as a result of their disease if they had Medicaid coverage (hazard ratio [HR], 1.44; 95% CI, 1.41 to 1.47; P < .001) or no insurance (HR, 1.47; 95% CI, 1.42 to 1.51; P < .001) compared with non-Medicaid insurance. CONCLUSION Among patients with the 10 most deadly cancers, those with Medicaid coverage or without insurance were more likely to present with advanced disease, were less likely to receive cancer-directed surgery and/or radiation therapy, and experienced worse survival.


Laryngoscope | 2006

Optical coherence tomography of laryngeal cancer.

William B. Armstrong; James M. Ridgway; David E. Vokes; Shuguang Guo; Jorge Perez; Ryan P. Jackson; Mai Gu; Jianping Su; Roger L. Crumley; Terry Y. Shibuya; Usama Mahmood; Zhongping Chen; Brian J. F. Wong

Objectives: Optical coherence tomography (OCT) is a high‐resolution optical imaging technique that produces cross‐sectional images of living tissues using light in a manner similar to ultrasound. This prospective study evaluated the ability of OCT to identify the characteristics of laryngeal cancer and measure changes in the basement membrane, tissue microstructure, and the transition zone at the edge of tumors.


International Journal of Radiation Oncology Biology Physics | 2014

Risk of Late Toxicity in Men Receiving Dose-Escalated Hypofractionated Intensity Modulated Prostate Radiation Therapy: Results From a Randomized Trial

Karen E. Hoffman; K. Ranh Voong; Thomas J. Pugh; Heath D. Skinner; Lawrence B. Levy; Vinita Takiar; Seungtaek Choi; Weiliang Du; Steven J. Frank; Jennifer L. Johnson; James E. Kanke; Rajat J. Kudchadker; Andrew K. Lee; Usama Mahmood; Sean E. McGuire; Deborah A. Kuban

OBJECTIVE To report late toxicity outcomes from a randomized trial comparing conventional and hypofractionated prostate radiation therapy and to identify dosimetric and clinical parameters associated with late toxicity after hypofractionated treatment. METHODS AND MATERIALS Men with localized prostate cancer were enrolled in a trial that randomized men to either conventionally fractionated intensity modulated radiation therapy (CIMRT, 75.6 Gy in 1.8-Gy fractions) or to dose-escalated hypofractionated IMRT (HIMRT, 72 Gy in 2.4-Gy fractions). Late (≥90 days after completion of radiation therapy) genitourinary (GU) and gastrointestinal (GI) toxicity were prospectively evaluated and scored according to modified Radiation Therapy Oncology Group criteria. RESULTS 101 men received CIMRT and 102 men received HIMRT. The median age was 68, and the median follow-up time was 6.0 years. Twenty-eight percent had low-risk, 71% had intermediate-risk, and 1% had high-risk disease. There was no difference in late GU toxicity in men treated with CIMRT and HIMRT. The actuarial 5-year grade ≥2 GU toxicity was 16.5% after CIMRT and 15.8% after HIMRT (P=.97). There was a nonsignificant numeric increase in late GI toxicity in men treated with HIMRT compared with men treated with CIMRT. The actuarial 5-year grade ≥2 GI toxicity was 5.1% after CIMRT and 10.0% after HIMRT (P=.11). In men receiving HIMRT, the proportion of rectum receiving 36.9 Gy, 46.2 Gy, 64.6 Gy, and 73.9 Gy was associated with the development of late GI toxicity (P<.05). The 5-year actuarial grade ≥2 GI toxicity was 27.3% in men with R64.6Gy ≥ 20% but only 6.0% in men with R64.6Gy < 20% (P=.016). CONCLUSIONS Dose-escalated IMRT using a moderate hypofractionation regimen (72 Gy in 2.4-Gy fractions) can be delivered safely with limited grade 2 or 3 late toxicity. Minimizing the proportion of rectum that receives moderate and high dose decreases the risk of late rectal toxicity after this hypofractionation regimen.


Journal of Clinical Oncology | 2016

Improved Survival With Prostate Radiation in Addition to Androgen Deprivation Therapy for Men With Newly Diagnosed Metastatic Prostate Cancer

Chad G. Rusthoven; Bernard L. Jones; Thomas W. Flaig; E. David Crawford; Matthew Koshy; David J. Sher; Usama Mahmood; Ronald C. Chen; Brian F. Chapin; Brian D. Kavanagh; Thomas J. Pugh

PURPOSE There is growing interest in the role of local therapies, including external beam radiotherapy (RT), for men with metastatic prostate cancer (mPCa). We used the National Cancer Database (NCDB) to evaluate the overall survival (OS) of men with mPCa treated with androgen deprivation (ADT) with and without prostate RT. METHODS The NCDB was queried for men with newly diagnosed mPCa, all treated with ADT, with complete datasets for RT, surgery, prostate-specific antigen (PSA) level, Gleason score, and Charlson-Deyo comorbidity score. OS was analyzed using the Kaplan-Meier method, log-rank test, Cox proportional hazards models, and propensity score-matched analyses. RESULTS From 2004 to 2012, 6,382 men with mPCa were identified, including 538 (8.4%) receiving prostate RT. At a median follow-up of 5.1 years, the addition of prostate RT to ADT was associated with improved OS on univariate (P < .001) and multivariate analysis (hazard ratio, 0.624; 95% CI, 0.551 to 0.706; P < .001) adjusted for age, year, race, comorbidity score, PSA level, Gleason score, T stage, N stage, chemotherapy administration, treating facility, and insurance status. Propensity score analysis with matched baseline characteristics demonstrated superior median (55 v 37 months) and 5-year OS (49% v 33%) with prostate RT plus ADT compared with ADT alone (P < .001). Landmark analyses limited to long-term survivors of ≥1, ≥3, and ≥5 years demonstrated improved OS with prostate RT in all subsets (all P < .05). Secondary analyses comparing the survival outcomes for patients treated with therapeutic dose RT plus ADT versus prostatectomy plus ADT during the same time interval demonstrated no significant differences in OS, whereas both therapies were superior to ADT alone. CONCLUSION In this large contemporary analysis, men with mPCa receiving prostate RT and ADT lived substantially longer than men treated with ADT alone. Prospective trials evaluating local therapies for mPCa are warranted.


Laryngoscope | 2007

Imaging of the Pediatric Airway Using Optical Coherence Tomography

James M. Ridgway; Gurpreet S. Ahuja; Shuguang Guo; Jianping Su; Usama Mahmood; Zhongping Chen; Brian J. F. Wong

Objectives: Optical coherence tomography (OCT) is an imaging modality that uses a broadband light source to produce high‐resolution cross‐sectional images in living tissue (8–20 μm). A prospective study of normal, benign, and pathologic tissues in the pediatric airway was conducted to assess the utility of OCT technology in characterizing the microanatomy of the pediatric upper aerodigestive tract in vivo.


Respiration | 2005

Evaluation of Tracheal Imaging by Optical Coherence Tomography

Sukgu Han; Naglaa H. El-Abbadi; Nevine Hanna; Usama Mahmood; Reza Mina-Araghi; Woong Gyu Jung; Zhongping Chen; Henri G. Colt; Matthew Brenner

Background: Optical coherence tomography (OCT) is a new technology capable of generating high resolution cross-sectional images of complex tissue in real time. Analogous to ultrasound, OCT measures backscattered light intensity using coherence interferometery to construct topographical images of complex tissue. Since OCT uses infrared light rather than acoustic waves, its spatial resolution is exceptionally high (2–10 µm). Recent advances in data acquisition, analysis, and processing enable real-time imaging, and make OCT a potentially valuable tool for pulmonary airway diagnostic applications, including assisting directed airway biopsies. Objective: This study evaluates feasibility of OCT for delineating proximal airway microstructures in various animal as well as human tracheas. Methods: Excised trachea samples from New Zealand white rabbits, Duroc pigs, and human trachea were imaged using a compact, 1,300-nm broad-band superluminescent-diode-based prototype fiber OCT device we constructed. The resulting structural OCT images were compared to conventional hematoxilin and eosin (HE) stained histological sections from the same samples. Results: OCT was able to delineate microstructures such as the epithelium, mucosa, cartilage, and glands in all samples. Conclusion: These findings suggest that integration of OCT with flexible fiberoptic bronchoscopy could enhance pulmonary diagnostic medicine and detection of pathologic tissue changes in various respiratory diseases.


Brachytherapy | 2013

Declining use of brachytherapy for the treatment of prostate cancer

Usama Mahmood; Thomas J. Pugh; Steven J. Frank; Lawrence B. Levy; Gary V. Walker; Waqar Haque; Matthew Koshy; William J. Graber; David A. Swanson; Karen E. Hoffman; Deborah A. Kuban; Andrew G. Lee

PURPOSE To analyze the recent trends in the utilization of external beam radiation therapy (EBRT) and brachytherapy (BT) for the treatment of prostate cancer. METHODS AND MATERIALS Using the Surveillance, Epidemiology, and End Results (SEER) database, information was obtained for all patients diagnosed with localized prostate adenocarcinoma between 2004 and 2009 who were treated with radiation as local therapy. We evaluated the utilization of BT, EBRT, and combination BT+EBRT by the year of diagnosis and performed a multivariable analysis to determine the predictors of BT as treatment choice. RESULTS Between 2004 and 2009, EBRT monotherapy use increased from 55.8% to 62.0%, whereas all BT use correspondingly decreased from 44.2% to 38.0% (BT-only use decreased from 30.4% to 25.6%, whereas BT+EBRT use decreased from 13.8% to 12.3%). The decline of BT utilization differed by patient race, SEER registry, median county income, and National Comprehensive Cancer Network risk categorization (all p<0.001), but not by patient age (p=0.763) or marital status (p=0.193). Multivariable analysis found that age, race, marital status, SEER registry, median county income, and National Comprehensive Cancer Network risk category were independent predictors of BT as treatment choice (all p<0.001). Moreover, after controlling for all available patient and tumor characteristics, there was decreasing utilization of BT with increasing year of diagnosis (odds ratio for BT=0.920, 95% confidence interval: 0.911-0.929, p<0.001). CONCLUSIONS Our analysis reveals decreasing utilization of BT for prostate cancer. This finding has significant implications in terms of national health care expenditure.


International Journal of Radiation Oncology Biology Physics | 2011

Similar survival with breast conservation therapy or mastectomy in the management of young women with early-stage breast cancer

Usama Mahmood; Christopher J. Morris; Geoffrey Neuner; Matthew Koshy; Susan Kesmodel; Robert Buras; Saranya Chumsri; Ting Bao; Katherine Tkaczuk; S.J. Feigenberg

PURPOSE To evaluate survival outcomes of young women with early-stage breast cancer treated with breast conservation therapy (BCT) or mastectomy, using a large, population-based database. METHODS AND MATERIALS Using the Surveillance, Epidemiology, and End Results (SEER) database, information was obtained for all female patients, ages 20 to 39 years old, diagnosed with T1-2 N0-1 M0 breast cancer between 1990 and 2007, who underwent either BCT (lumpectomy and radiation treatment) or mastectomy. Multivariable and matched pair analyses were performed to compare overall survival (OS) and cause-specific survival (CSS) of patients undergoing BCT and mastectomy. RESULTS A total of 14,764 women were identified, of whom 45% received BCT and 55% received mastectomy. Median follow-up was 5.7 years (range, 0.5-17.9 years). After we accounted for all patient and tumor characteristics, multivariable analysis found that BCT resulted in OS (hazard ratio [HR], 0.93; 95% confidence interval [CI], 0.83-1.04; p = 0.16) and CSS (HR, 0.93; CI, 0.83-1.05; p = 0.26) similar to that of mastectomy. Matched pair analysis, including 4,644 BCT and mastectomy patients, confirmed no difference in OS or CSS: the 5-, 10-, and 15-year OS rates for BCT and mastectomy were 92.5%, 83.5%, and 77.0% and 91.9%, 83.6%, and 79.1%, respectively (p = 0.99), and the 5-, 10-, and 15-year CSS rates for BCT and mastectomy were 93.3%, 85.5%, and 79.9% and 92.5%, 85.5%, and 81.9%, respectively (p = 0.88). CONCLUSIONS Our analysis of this population-based database suggests that young women with early-stage breast cancer have similar survival rates whether treated with BCT or mastectomy. These patients should be counseled appropriately regarding their treatment options and should not choose a mastectomy based on the assumption of improved survival.


Brachytherapy | 2011

Accelerated partial breast irradiation via brachytherapy: a patterns-of-care analysis with ASTRO consensus statement groupings.

Zain A. Husain; Usama Mahmood; Alexandra L. Hanlon; Geoffrey Neuner; Robert Buras; K. Tkaczuk; S.J. Feigenberg

PURPOSE The 2002 Food and Drug Administration approval of the MammoSite catheter (Hologic, Inc., Beford, MA) led to a surge of interest in accelerated partial breast irradiation (APBI). Until recently, guidelines as to the optimal candidates for this treatment were unavailable. We performed a patterns-of-care analysis for patients undergoing breast brachytherapy and compared these results with the American Society for Radiation Oncology (ASTRO) consensus statement. METHODS AND MATERIALS The Surveillance, Epidemiology, and End Results database was used to examine female breast cancer patients treated with brachytherapy between 2002 and 2007. The patients were then categorized into suitable, cautionary, and unsuitable groups based on the ASTRO guidelines. RESULTS We identified 4172 female breast cancer patients treated within the stated years. The number of brachytherapy cases increased nearly 10-fold over the time period studied from 163 in 2002 to 1427 in 2007 (p<0.0001). Patients with data missing were excluded, leaving a total of 3593 patients available for analysis. The mean patient age was 64 years. Most patients had small (<2cm in 80.9%) estrogen receptor-positive (86.7%) invasive (88.6%) tumors. The percentage of patients treated for ductal carcinoma in situ increased with time (p<0.001), whereas the percentage of patients treated with positive lymph nodes decreased with time (p<0.001). Using the data available, 1369 (38.1%), 1563 (43.5%), and 661 (18.3%) patients were characterized as suitable, cautionary, and unsuitable, respectively. CONCLUSIONS More than 60% of patients who received APBI via brachytherapy would fall into the ASTRO cautionary or unsuitable groupings. This is the largest patterns-of-care analysis for APBI patients and serves as a baseline for future comparison.

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Thomas J. Pugh

University of Colorado Denver

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Steven J. Frank

University of Texas MD Anderson Cancer Center

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Rajat J. Kudchadker

University of Texas MD Anderson Cancer Center

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Deborah A. Kuban

University of Texas MD Anderson Cancer Center

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Karen E. Hoffman

University of Texas MD Anderson Cancer Center

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Sean E. McGuire

University of Texas MD Anderson Cancer Center

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Teresa L. Bruno

University of Texas MD Anderson Cancer Center

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David A. Swanson

University of Texas MD Anderson Cancer Center

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Seungtaek Choi

University of Texas MD Anderson Cancer Center

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