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Robert Timmerman

Bio: Robert Timmerman is an academic researcher from University of Texas Southwestern Medical Center. The author has contributed to research in topics: Radiation therapy & Radiosurgery. The author has an hindex of 63, co-authored 332 publications receiving 20711 citations. Previous affiliations of Robert Timmerman include University of Texas at Dallas & University of Texas at Austin.


Papers
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Journal ArticleDOI
17 Mar 2010-JAMA
TL;DR: Patients with inoperable non-small cell lung cancer who received stereotactic body radiation therapy had a survival rate of 55.8% at 3 years, high rates of local tumor control, and moderate treatment-related morbidity.
Abstract: Context Patients with early stage but medically inoperable lung cancer have a poor rate of primary tumor control (30%-40%) and a high rate of mortality (3-year survival, 20%-35%) with current management. Objective To evaluate the toxicity and efficacy of stereotactic body radiation therapy in a high-risk population of patients with early stage but medically inoperable lung cancer. Design, Setting, and Patients Phase 2 North American multicenter study of patients aged 18 years or older with biopsy-proven peripheral T1-T2N0M0 non–small cell tumors (measuring Main Outcome Measures The primary end point was 2-year actuarial primary tumor control; secondary end points were disease-free survival (ie, primary tumor, involved lobe, regional, and disseminated recurrence), treatment-related toxicity, and overall survival. Results A total of 59 patients accrued, of which 55 were evaluable (44 patients with T1 tumors and 11 patients with T2 tumors) with a median follow-up of 34.4 months (range, 4.8-49.9 months). Only 1 patient had a primary tumor failure; the estimated 3-year primary tumor control rate was 97.6% (95% confidence interval [CI], 84.3%-99.7%). Three patients had recurrence within the involved lobe; the 3-year primary tumor and involved lobe (local) control rate was 90.6% (95% CI, 76.0%-96.5%). Two patients experienced regional failure; the local-regional control rate was 87.2% (95% CI, 71.0%-94.7%). Eleven patients experienced disseminated recurrence; the 3-year rate of disseminated failure was 22.1% (95% CI, 12.3%-37.8%). The rates for disease-free survival and overall survival at 3 years were 48.3% (95% CI, 34.4%-60.8%) and 55.8% (95% CI, 41.6%-67.9%), respectively. The median overall survival was 48.1 months (95% CI, 29.6 months to not reached). Protocol-specified treatment-related grade 3 adverse events were reported in 7 patients (12.7%; 95% CI, 9.6%-15.8%); grade 4 adverse events were reported in 2 patients (3.6%; 95% CI, 2.7%-4.5%). No grade 5 adverse events were reported. Conclusion Patients with inoperable non–small cell lung cancer who received stereotactic body radiation therapy had a survival rate of 55.8% at 3 years, high rates of local tumor control, and moderate treatment-related morbidity.

2,202 citations

Journal ArticleDOI
TL;DR: The task group report includes a review of the literature to identify reported clinical findings and expected outcomes for this treatment modality.
Abstract: Task Group 101 of the AAPM has prepared this report for medical physicists, clinicians, and therapists in order to outline the best practice guidelines for the external-beam radiation therapy technique referred to as stereotactic body radiation therapy (SBRT). The task group report includes a review of the literature to identify reported clinical findings and expected outcomes for this treatment modality. Information is provided for establishing a SBRT program, including protocols, equipment, resources, and QA procedures. Additionally, suggestions for developing consistent documentation for prescribing, reporting, and recording SBRT treatment delivery is provided.

1,586 citations

Journal ArticleDOI
TL;DR: High rates of local control are achieved with this SBRT regimen in medically inoperable patients with stage I NSCLC, and this regimen should not be used for patients with tumors near the central airways due to excessive toxicity.
Abstract: Purpose Surgical resection is standard therapy in stage I non–small-cell lung cancer (NSCLC); however, many patients are inoperable due to comorbid diseases. Building on a previously reported phase I trial, we carried out a prospective phase II trial using stereotactic body radiation therapy (SBRT) in this population. Patients and Methods Eligible patients included clinically staged T1 or T2 (≤ 7 cm), N0, M0, biopsy-confirmed NSCLC. All patients had comorbid medical problems that precluded lobectomy. SBRT treatment dose was 60 to 66 Gy total in three fractions during 1 to 2 weeks. Results All 70 patients enrolled completed therapy as planned and median follow-up was 17.5 months. The 3-month major response rate was 60%. Kaplan-Meier local control at 2 years was 95%. Altogether, 28 patients have died as a result of cancer (n = 5), treatment (n = 6), or comorbid illnesses (n = 17). Median overall survival was 32.6 months and 2-year overall survival was 54.7%. Grade 3 to 5 toxicity occurred in a total of 14 p...

1,340 citations

Journal ArticleDOI
TL;DR: The three-dimensional dose, volume, and outcome data for lung are reviewed in detail and it is confirmed that there is no evident threshold "tolerance dose-volume" levels and there are strong volume and fractionation effects.
Abstract: The three-dimensional dose, volume, and outcome data for lung are reviewed in detail. The rate of symptomatic pneumonitis is related to many dosimetric parameters, and there are no evident threshold "tolerance dose-volume" levels. There are strong volume and fractionation effects.

892 citations

Journal ArticleDOI
TL;DR: Use of SBRT results in high rates of local control in medically inoperable patients with Stage I NSCLC, and there was no significant survival difference between patients with peripheral vs. central tumors.
Abstract: Purpose The 50-month results of a prospective Phase II trial of stereotactic body radiation therapy (SBRT) in medically inoperable patients are reported. Methods and Materials A total of 70 medically inoperable patients had clinically staged T1 (34 patients) or T2 (36 patients) (≤7 cm), N0, M0, biopsy-confirmed non–small-cell lung carcinoma (NSCLC) and received SBRT as per our previously published reports. The SBRT treatment dose of 60-66 Gy was prescribed to the 80% isodose volume in three fractions. Results Median follow-up was 50.2 months (range, 1.4–64.8 months). Kaplan-Meier local control at 3 years was 88.1%. Regional (nodal) and distant recurrence occurred in 6 (8.6%) and 9 (12.9%) patients, respectively. Median survival (MS) was 32.4 months and 3-year overall survival (OS) was 42.7% (95% confidence interval [95% CI], 31.1–54.3%). Cancer-specific survival at 3 years was 81.7% (95% CI, 70.0–93.4%). For patients with T1 tumors, MS was 38.7 months (95% CI, 25.3–50.2) and for T2 tumors MS was 24.5 months (95% CI, 18.5–37.4) ( p = 0.194). Tumor volume (≤5 cc, 5–10 cc, 10–20 cc, >20 cc) did not significantly impact survival: MS was 36.9 months (95% CI, 18.1–42.9), 34.0 (95% CI, 16.9–57.1), 32.8 (95% CI, 21.3–57.8), and 21.4 months (95% CI, 17.8–41.6), respectively ( p = 0.712). There was no significant survival difference between patients with peripheral vs. central tumors (MS 33.2 vs. 24.4 months, p = 0.697). Grade 3 to 5 toxicity occurred in 5 of 48 patients with peripheral lung tumors (10.4%) and in 6 of 22 patients (27.3%) with central tumors (Fisher's exact test, p = 0.088). Conclusion Based on our study results, use of SBRT results in high rates of local control in medically inoperable patients with Stage I NSCLC.

784 citations


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Journal ArticleDOI
01 Nov 2009-Thyroid
TL;DR: Evidence-based recommendations are developed to inform clinical decision-making in the management of thyroid nodules and differentiated thyroid cancer and represent, in the authors' opinion, contemporary optimal care for patients with these disorders.
Abstract: Background: Thyroid nodules are a common clinical problem, and differentiated thyroid cancer is becoming increasingly prevalent. Since the American Thyroid Association's (ATA's) guidelines for the management of these disorders were revised in 2009, significant scientific advances have occurred in the field. The aim of these guidelines is to inform clinicians, patients, researchers, and health policy makers on published evidence relating to the diagnosis and management of thyroid nodules and differentiated thyroid cancer. Methods: The specific clinical questions addressed in these guidelines were based on prior versions of the guidelines, stakeholder input, and input of task force members. Task force panel members were educated on knowledge synthesis methods, including electronic database searching, review and selection of relevant citations, and critical appraisal of selected studies. Published English language articles on adults were eligible for inclusion. The American College of Physicians Guideline Gr...

10,501 citations

Journal ArticleDOI
TL;DR: It is reported that angiogenesis inhibitors targeting the VEGF pathway demonstrate antitumor effects in mouse models of pancreatic neuroendocrine carcinoma and glioblastoma but concomitantly elicit tumor adaptation and progression to stages of greater malignancy, with heightened invasiveness and in some cases increased lymphatic and distant metastasis.

2,303 citations