International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2002
Dose escalation using conformal high-dose-rate brachytherapy improves outcome in unfavorable prostate cancer.
To overcome radioresistance for patients with unfavorable prostate cancer, a prospective trial of pelvic external beam irradiation (EBRT) interdigitated with dose-escalating conformal high-dose-rate (HDR) prostate brachytherapy was performed. ⋯ Pelvic EBRT interdigitated with transrectal ultrasound-guided real-time conformal HDR prostate brachytherapy boost is both a precise dose delivery system and a very effective treatment for unfavorable prostate cancer. We demonstrated an incremental beneficial effect on biochemical control and cause-specific survival with higher doses. These results, coupled with the low risk of complications, the advantage of not being radioactive after implantation, and the real-time interactive planning, define a new standard for treatment.
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Int. J. Radiat. Oncol. Biol. Phys. · Jun 2002
Biologically effective dose for permanent prostate brachytherapy taking into account postimplant edema.
To study the influence of radiobiologic and physical parameters and parameters related to edema on the biologically effective dose (BED) for permanent prostate implants and to determine the optimal timing of seed reconstruction for BED calculation. ⋯ The maximal BED depends strongly on the value of alpha, the potential tumor doubling time, and the choice of isotope. If prostate volume increase due to edema is not taken into account, the BED will be underestimated shortly after the implantation and overestimated if the calculations are based on images taken several months after implantation. The optimal timing of BED evaluation for 125I seed implants and typical prostate edema values is 25 days after implantation.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2002
Activation of the nuclear transcription factor kappaB (NFkappaB) and differential gene expression in U87 glioma cells after exposure to the cytoprotector amifostine.
Amifostine has been approved as a therapy to decrease the incidence of moderate-to-severe xerostomia in patients undergoing postoperative radiation treatment for head-and-neck cancer. As a reducing agent capable of participating in intracellular reductive/oxidative processes, it has the potential to affect redox-sensitive transcription factors and gene expression. Amifostine's active free thiol WR-1065 was investigated to determine its effect on nuclear transcription factor kappaB (NFkappaB) activation and subsequent gene expression in U87 glioma cells. ⋯ The redox-sensitive transcription factor NFkappaB can be activated in U87 glioma cells by the active thiol form of the cytoprotector amifostine. Activation of NFkappaB by the antioxidant WR-1065 is accompanied by a reduced expression of the oncogene c-myc and an enhanced expression of the antioxidant gene MnSOD, a gene whose expression in tumor cells is relatively low, but when overexpressed has been correlated with a suppression of the malignant phenotype. Activation of NFkappaB by WR-1065, however, results in selective rather than global changes in the expression of genes containing NFkappaB-responsive elements.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2002
Gastrointestinal toxicity of transperineal interstitial prostate brachytherapy.
To characterize the severity and time course of rectal toxicity following transperineal prostate brachytherapy using prospectively recorded data, and to determine factors associated with toxicity. ⋯ Most patients with rectal toxicity have very mild symptoms. There is a small risk of severe late toxicity. External beam radiation, higher stage, and race are associated with toxicity.
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Int. J. Radiat. Oncol. Biol. Phys. · May 2002
Clinical TrialObjective assessment of swallowing dysfunction and aspiration after radiation concurrent with chemotherapy for head-and-neck cancer.
To objectively assess swallowing function after an intensive chemoradiation regimen for locally advanced head-and-neck cancer and to assess the clinical implications of swallowing dysfunction. ⋯ After intensive chemoradiotherapy, significant objective swallowing dysfunction is prevalent. It promotes aspiration, which may not elicit a cough reflex and may be associated with pneumonia. Aspiration pneumonia may be an underdocumented complication of chemoradiotherapy for head-and-neck cancer. Future studies should examine whether routine post-therapy videofluoroscopy and training aspirating patients in safe swallowing strategies can reduce this risk.