International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Application of the No Action Level (NAL) protocol to correct for prostate motion based on electronic portal imaging of implanted markers.
To evaluate the efficacy of the No Action Level (NAL) off-line correction protocol in the reduction of systematic prostate displacements as determined from electronic portal images (EPI) using implanted markers. ⋯ The NAL protocol based on marker positions in EPI halved the composite systematic displacements using only three imaged fractions per patient, and thus allowed for a significant reduction of planning margins. Although large rotations of the prostate, and time trends therein, were observed, the net impact on the measured displacements and on the accuracy obtained with NAL was small.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Randomized Controlled Trial Clinical TrialGastrointestinal toxicity and its relation to dose distributions in the anorectal region of prostate cancer patients treated with radiotherapy.
To study the correlations between the dose distributions in the anorectal region and late GI symptoms in patients treated for localized prostate carcinoma. ⋯ We found evidence that complaints originate from specific regions of the irradiated lower GI tract. Bleeding and mucus loss are probably related to irradiation of the upper part of the rectum. Soiling and fecal incontinence are more likely related to the dose to the anal canal and the lower part of the rectum.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Randomized Controlled Trial Clinical TrialWhat pretreatment prostate-specific antigen level warrants long-term androgen deprivation?
Several large randomized prospective studies have demonstrated a survival benefit with the addition of long-term androgen deprivation to definitive radiotherapy for patients with Gleason score 8-10 or T3-T4 prostate cancer. However, these studies were performed before the routine use of prostate-specific antigen (PSA) measurement. The purpose of this study was to determine what pretreatment (initial) PSA (iPSA) level, if any, warrants the addition of long-term androgen deprivation in the PSA era. ⋯ Recursive partitioning techniques defined an iPSA cutpoint of 30 ng/mL for delineating intermediate vs. high risk. Patients with a PSA level >30 ng/mL in the absence of Gleason score >7 or T3 disease do poorly when treated with radiotherapy alone and should be considered for long-term androgen deprivation or other aggressive systemic therapy.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Pretreatment anemia is correlated with the reduced effectiveness of radiation and concurrent chemotherapy in advanced head and neck cancer.
Pretreatment anemia is an adverse prognostic variable in squamous cell head-and-neck cancer (HNC) patients treated with radiotherapy (RT) alone. Tumor hypoxia is an adverse parameter for treatment with RT alone or with RT and concurrent chemotherapy (CCT). Tumor hypoxia is more prevalent in patients who present with pretreatment hemoglobin (Hgb) concentrations less than 13 g/dL. RT/CCT improves survival over RT alone in advanced HNC, and its use is becoming more widespread. This study was performed to evaluate whether pretreatment Hgb less than 13 g/dL was correlated with treatment outcome in patients with advanced HNC treated with a uniform regimen of RT/CCT. ⋯ Pretreatment Hgb less than 13 g/dL is correlated with adverse outcomes in advanced HNC patients treated with RT/CCT. Whether anemia actually causes poor outcomes remains unknown. The therapeutic effect of anemia correction is being evaluated in prospective trials.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Dosimetric advantages of IMRT simultaneous integrated boost for high-risk prostate cancer.
A sequential two-phase process, initial and boost irradiation, is the common practice for the radiotherapy management of high-risk prostate cancer. In this work, we explore the feasibility of using intensity modulated radiation therapy (IMRT) simultaneous integrated boost (SIB), a single-phase process, to simultaneously deliver high dose to the prostate and lower dose to the pelvic nodes. In addition, we introduce the concept of voxel-equivalent dose for the comparison of treatment plans. ⋯ A new IMRT simultaneous integrated boost strategy that irradiates prostate via hypofractionation while irradiating pelvic nodes with the conventional fractionation is proposed for high-risk prostate cancer. Compared to the conventional two-phase treatment, the proposed SIB technique offers potential advantages, including better sparing of critical structures, more efficient delivery, shorter treatment duration, and better biologic effectiveness.