International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Dose-response characteristics of low- and intermediate-risk prostate cancer treated with external beam radiotherapy.
In this era of dose escalation, the benefit of higher radiation doses for low-risk prostate cancer remains controversial. For intermediate-risk patients, the data suggest a benefit from higher doses. However, the quantitative characterization of the benefit for these patients is scarce. We investigated the radiation dose-response relation of tumor control probability in low-risk and intermediate-risk prostate cancer patients treated with radiotherapy alone. We also investigated the differences in the dose-response characteristics using the American Society for Therapeutic Radiology and Oncology (ASTRO) definition vs. an alternative biochemical failure definition. ⋯ A dose-response relation was found using the ASTRO definition for low-risk prostate cancer. However, we found only marginal or no dose-response relation when the CN + 2 definition was used. Most of the benefit from the higher doses derived from low-risk patients with higher PSA levels. In all cases, little projected gain appears to exist at doses >78 Gy for these patients. A dose-response relation was noted for the intermediate-risk patients using either the CN + 2 or ASTRO definition. Most of the benefit from the higher doses also derived from the intermediate-risk patients with higher PSA levels. Some room for improvement appears to exist with additional dose increases in this group.
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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
Radiochemotherapy in the conservative treatment of anal canal carcinoma: retrospective analysis of results and radiation dose effectiveness.
This retrospective analysis reports the results on patients with anal canal carcinoma treated by combined radiotherapy and chemotherapy. ⋯ This analysis suggests that the treatment scheme employed was effective for anal sphincter preservation and local control; however, the incidence of distant metastases was relatively high. The clinical stage was the main prognostic factor for overall survival. Local control was higher in patients treated with doses of more than 50 Gy at primary tumor. The high incidence of inguinal failure implies the need for elective RT in this region.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2005
Randomized Controlled Trial Multicenter Study Clinical TrialAccelerated versus conventional fractionated postoperative radiotherapy for advanced head and neck cancer: results of a multicenter Phase III study.
To determine whether, in the postoperative setting, accelerated fractionation (AF) radiotherapy (RT) yields a superior locoregional control rate compared with conventional fractionation (CF) RT in locally advanced squamous cell carcinomas of the oral cavity, oropharynx, larynx, or hypopharynx. ⋯ Accelerated fractionation does not seem to be worthwhile for squamous cell carcinoma of the head and neck after resection; however, AF might be an option for patients who delay starting RT.