International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Randomized Controlled Trial Clinical TrialEvidence for efficacy without increased toxicity of hypofractionated radiotherapy for prostate carcinoma: early results of a Phase III randomized trial.
We performed a randomized trial to compare the GI and urogenital toxicity of radiotherapy (RT) for localized (confined to the organ), early-stage (T1-T2N0M0, TNM classification) carcinoma of the prostate, using a conventional (64 Gy in 32 fractions within 6.5 weeks) vs. a hypofractionated (55 Gy in 20 fractions within 4 weeks) schedule and to determine the efficacy of the respective treatment schedules. ⋯ RT for prostate carcinoma, using a three- or four-field 6-23-MV photon technique without posterior shielding of the lateral fields, is an underestimated cause of persistent GI morbidity. The incidence of clinically significant GI and urogenital toxicity after conventional and hypofractionated RT appears to be similar. Hypofractionated RT for carcinoma of the prostate seems just as effective as conventional RT after a median follow-up approaching 4 years.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Role of IMRT in reducing penile doses in dose escalation for prostate cancer.
In three-dimensional conformal radiotherapy (3D-CRT), penile tissues adjacent to the prostate are exposed to significant doses of radiation. This is likely to be a factor in development of posttreatment erectile dysfunction. In this study, we investigate whether intensity-modulated radiation therapy (IMRT) leads to lower radiation exposure to proximal penile tissues (PPT) when compared with 3D-CRT. ⋯ IMRT allows for dose escalation in prostate cancer while keeping penile tissue doses significantly lower compared to conformal radiotherapy. This may result in improved potency rates over current results observed with 3D-CRT.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Comparative StudyStereotactic radiosurgery provides equivalent tumor control to Simpson Grade 1 resection for patients with small- to medium-size meningiomas.
To compare tumor control rates after surgical resection or stereotactic radiosurgery for patients with small- to medium-size intracranial meningiomas. ⋯ The PFS rate after radiosurgery was equivalent to that after resection of a Simpson Grade 1 tumor and was superior to Grade 2 and 3-4 resections in our study. If long-term follow-up confirms the high tumor control rate and low morbidity of radiosurgery, this technique will likely become the preferred treatment for most patients with small- to moderate-size meningiomas without symptomatic mass effect.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Improved conformality and decreased toxicity with intraoperative computer-optimized transperineal ultrasound-guided prostate brachytherapy.
We have developed an intraoperative three-dimensional (3D) conformal treatment planning system for permanent prostate implantation in an effort to reduce toxicity further and improve the accuracy of this procedure. We report the preliminary outcome of patients with localized prostate cancer treated with this approach. ⋯ The integration of an intraoperative optimization program with 3D dose evaluation throughout the target volume for prostate brachytherapy has consistently achieved excellent target coverage with the PD, and the dose levels to normal tissues were effectively restricted to tolerance ranges. These changes have led to a more favorable acute toxicity profile for patients treated with this technique without compromising biochemical control.
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Int. J. Radiat. Oncol. Biol. Phys. · Mar 2003
Clinical implications of incorporating heterogeneity corrections in mantle field irradiation.
Patient dose calculations for mantle-field irradiation have traditionally been performed using homogeneous, water phantom data. The advent of computed tomography (CT)-based treatment planning now permits dose calculations to be corrected for actual patient density. Incorporation of full heterogeneity corrections is desirable, because calculations performed in this fashion more closely represent the actual dose delivered to the patient. In preparation for full clinical implementation of heterogeneity corrections in mantle irradiation, an evaluation of possible changes in dosimetry when transitioning from treatment plans generated without heterogeneity corrections to treatment plans that incorporated full heterogeneity corrections is presented. ⋯ In all patient treatment plans evaluated, no significant dosimetric differences were observed between heterogeneity-corrected and heterogeneity-uncorrected treatment plans. However, unpredictable differences in the prescription isodose (30.6 Gy) were observed. The differences in coverage at the 90% isodose volume were negligible. The dose administered to lung in heterogeneity-corrected plans demonstrates a higher dose overall, with the greatest increase occurring at volumes receiving at least 20 Gy. In light of these small dosimetric differences, we believe that heterogeneity corrections can be incorporated into full mantle-field treatment planning.