Publications by authors named "David C Beyer"

Purpose: To determine whether addition of external beam radiation therapy (EBRT) to brachytherapy (BT) (COMBO) compared with BT alone would improve 5-year freedom from progression (FFP) in intermediate-risk prostate cancer.

Methods: Men with prostate cancer stage cT1c-T2bN0M0, Gleason Score (GS) 2-6 and prostate-specific antigen (PSA) 10-20 or GS 7, and PSA < 10 were eligible. The COMBO arm was EBRT (45 Gy in 25 fractions) to prostate and seminal vesicles followed by BT prostate boost (110 Gy if 125-Iodine, 100 Gy if 103-Pd).

View Article and Find Full Text PDF

Background: In breast cancer treatment, marking the tumor bed is an important aspect of the surgical component of therapy. Clear delineation of the tumor bed allows radiation oncologists a defined target for planning and delivering postoperative radiation therapy (XRT). Tumor bed marking also allows radiographic follow-up of the tumor bed on subsequent breast imaging.

View Article and Find Full Text PDF

Purpose: There is considerable interest in very short (ultrahypofractionated) radiation therapy regimens to treat prostate cancer based on potential radiobiological advantages, patient convenience, and resource allocation benefits. Our objective is to demonstrate that detectable changes in health-related quality of life measured by the bowel and urinary domains of the Expanded Prostate Cancer Index Composite (EPIC-50) were not substantially worse than baseline scores.

Methods And Materials: NRG Oncology's RTOG 0938 is a nonblinded randomized phase 2 study of National Comprehensive Cancer Network low-risk prostate cancer in which each arm is compared with a historical control.

View Article and Find Full Text PDF

Background: Phase 3 trials have demonstrated a benefit from adjuvant radiation therapy (ART) for men who have adverse factors at radical prostatectomy (RP). However, some patients have a high risk of progression despite ART. The role of systemic therapy with ART in this high-risk group remains to be defined.

View Article and Find Full Text PDF

Introduction: We evaluate the safety, tolerability and impact on therapy of an absorbable hydrogel perirectal spacer (SpaceOAR® system) designed to reduce the rectal radiation dose during prostate cancer radiotherapy.

Methods: A multicenter, pivotal, randomized controlled trial was conducted in 222 men with stage T1 or T2 prostate cancer treated to 79.2 Gy with image guided intensity modulated radiation therapy in 44 fractions.

View Article and Find Full Text PDF

Intensity-modulated radiation therapy (IMRT) is a complex technique for the delivery of radiation therapy preferentially to target structures while minimizing doses to adjacent normal critical structures. It is widely utilized in the treatment of a variety of clinical indications in radiation oncology, including tumors of the central nervous system, head and neck, breast, prostate, gastrointestinal tract, and gynecologic organs, as well as in situations where previous radiation therapy has been delivered, and has allowed for significant therapeutic advances in many clinical areas. IMRT treatment planning and delivery is a complex process.

View Article and Find Full Text PDF

Effective transcription, replication, and maintenance of the genome require a diverse set of molecular machines to perform the many chemical transactions that constitute these processes. Many of these machines use single-stranded nucleic acids as templates, and their actions are often regulated by the participation of nucleic acids in multimeric structures and macromolecular assemblies that restrict access to chemical information. Superfamily II (SF2) DNA helicases and translocases are a group of molecular machines that remodel nucleic acid lattices and enable essential cellular processes to use the information stored in the duplex DNA of the packaged genome.

View Article and Find Full Text PDF

Transperineal permanent prostate brachytherapy is a safe and efficacious treatment option for patients with organ-confined prostate cancer. Careful adherence to established brachytherapy standards has been shown to improve the likelihood of procedural success and reduce the incidence of treatment-related morbidity. A collaborative effort of the American College of Radiology (ACR) and American Society for Therapeutic Radiation Oncology (ASTRO) has produced a practice guideline for permanent prostate brachytherapy.

View Article and Find Full Text PDF

DNA polymerases use either a bulky active site residue or a backbone segment to select against ribonucleotides in order to faithfully replicate cellular genomes. Here, we demonstrated that an active site mutation (Y12A) within Sulfolobus solfataricus DNA polymerase IV (Dpo4) caused an average increase of 220-fold in matched ribonucleotide incorporation efficiency and an average decrease of 9-fold in correct deoxyribonucleotide incorporation efficiency, leading to an average reduction of 2000-fold in sugar selectivity. Thus, the bulky side chain of Tyr12 is important for both ribonucleotide discrimination and efficient deoxyribonucleotide incorporation.

View Article and Find Full Text PDF

Health policy is developed in the United States through a complicated interplay of governmental and private agencies and businesses, physician organizations, and societies as well as a host of other private ventures. The end result is rarely precisely what any individual or group may desire as the consequences of any action are never entirely predictable. There are many pathways to influence policy development within this system, and many of these are influenced by physicians as individuals and through organized medical societies.

View Article and Find Full Text PDF

Purpose: This study is aimed at understanding and defining the current patterns of care with respect to prostate brachytherapy for patients with intermediate-risk localized disease in the combined academic and community setting.

Methods And Materials: A nomogram-based survey was developed at the Seattle Prostate Institute defining the accepted criteria for intermediate-risk prostate cancer. Patients were defined as having intermediate-risk prostate cancer if they met one of the following criteria: prostate-specific antigen (PSA) >10 ng/dL, Gleason score (GS) > or = 7, or cT2b or cT2c disease.

View Article and Find Full Text PDF

Purpose: To assess long-term prostate-specific antigen (PSA) outcome after permanent prostate brachytherapy (BT) and identify predictors of improved disease-free survival.

Methods And Materials: Eleven institutions combined data on 2,693 patients treated with permanent interstitial BT monotherapy for T1-T2 prostate cancer. Of these patients, 1,831 (68%) were treated with I-125 (median dose, 144 Gy) and 862 (32%) were treated with Pd-103 (median dose, 130 Gy).

View Article and Find Full Text PDF

Purpose: To assess prostate-specific antigen (PSA) failure definitions for patients with Stage T1-T2 prostate cancer treated by permanent prostate brachytherapy.

Methods And Materials: A total of 2,693 patients treated with radioisotopic implant as solitary treatment for T1-T2 prostatic adenocarcinoma were studied. All patients had a pretreatment PSA, were treated at least 5 years before analysis, 1988 to 1998, and did not receive hormonal therapy before recurrence.

View Article and Find Full Text PDF

Purpose: To review the impact of prior hormonal therapy on 10-year overall and prostate cancer specific survival after primary brachytherapy.

Methods And Materials: A retrospective review was performed on the Arizona Oncology Services tumor registry for 2,378 consecutive permanent prostate brachytherapy cases from 1988 through 2001. Hormonal therapy was administered before the implant in 464 patients for downsizing of the prostate or at the discretion of the referring physician.

View Article and Find Full Text PDF

Purpose: To evaluate 10-year survival rates after prostate brachytherapy and to assess the relative importance of pretreatment prostate-specific antigen (PSA) and Gleason score in predicting cancer death.

Materials And Methods: A retrospective review was performed on all patients treated with permanent brachytherapy for stage T1 or T2 primary prostate cancer at a single institution from December 1988 through June 30, 1998. The study cohort consisted of 1266 patients with a median follow-up of 4.

View Article and Find Full Text PDF

The options available for patients with recurrent prostate cancer are limited. Men who have failed external-beam irradiation as the primary treatment are rarely considered for potentially curative salvage therapy. Traditionally, only palliative treatments have been offered with hormonal intervention or simple observation.

View Article and Find Full Text PDF

Prostate cancer specialists routinely see patients with recurrent disease after external beam irradiation. Traditionally, only palliative treatments have been offered with hormonal intervention or simple observation. A significant, although as yet uncertain, percentage of these patients will have only locally recurrent cancer and thus are potentially candidates for curative salvage therapy.

View Article and Find Full Text PDF

A PHP Error was encountered

Severity: Warning

Message: fopen(/var/lib/php/sessions/ci_session42r6th6chil9ssmbl3chdq47f56qs31b): Failed to open stream: No space left on device

Filename: drivers/Session_files_driver.php

Line Number: 177

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once

A PHP Error was encountered

Severity: Warning

Message: session_start(): Failed to read session data: user (path: /var/lib/php/sessions)

Filename: Session/Session.php

Line Number: 137

Backtrace:

File: /var/www/html/index.php
Line: 316
Function: require_once