International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Sep 1999
Comparative StudyComparison of intensity-modulated tomotherapy with stereotactically guided conformal radiotherapy for brain tumors.
Intensity-modulated radiotherapy (IMRT) offers the potential to more closely conform dose distributions to the target, and spare organs at risk (OAR). Its clinical value is still being defined. The present study aims to compare IMRT with stereotactically guided conformal radiotherapy (SCRT) for patients with medium size convex-shaped brain tumors. ⋯ The Peacock method provided improved PTV coverage, albeit small, in this group of convex tumors. Although the OAR doses were higher using the Peacock plans, all doses remained within the clinically defined threshold and were clinically acceptable. Further improvements may be expected using other methods of IMRT planning that do not limit the treatment delivery to transaxial arcs. Each IMRT system needs to be individually assessed as the paradigm utilized may provide different outcomes.
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Int. J. Radiat. Oncol. Biol. Phys. · Sep 1999
The effect of patient position and treatment technique in conformal treatment of prostate cancer.
The relative value of prone versus supine positioning and axial versus nonaxial beam arrangements in the treatment of prostate cancer remains controversial. Two critical issues in comparing techniques are: 1) dose to critical normal tissues, and 2) prostate stabilization. ⋯ Prone flat positioning was advantageous over other positions and beam arrangements in rectal sparing. This study suggests that patient position is a more critical a factor in conformal therapy than beam arrangement, and may improve the safety of dose escalation.
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Int. J. Radiat. Oncol. Biol. Phys. · Sep 1999
Patients with stage I non-small cell lung carcinoma at postoperative risk for local recurrence, distant metastasis, and death: implications related to the design of clinical trials.
Patients with pathologically staged American Joint Committee on Cancer stage I (T1 N0 or T2 N0) non-small cell lung cancer have a favorable prognosis after complete surgical resection compared with patients with more advanced stages. Benefits of adjuvant therapy in this setting are unproved. However, there may be subgroups of patients with stage I disease at high enough risk for local recurrence to prompt consideration of adjuvant or neoadjuvant radiation therapy. Likewise, there may be subgroups of patients at high enough risk for distant metastasis to justify the evaluation of chemotherapy. ⋯ Incorporating the aforementioned factors into regression tree analyses, three risk groups were identified with respect to FFLR. Two each were identified for FFDM and for survival. For each of these three end-points, the differences in outcomes for each risk group were found to be both statistically and clinically significant. These risk groups may be useful in the future design of phase III trials evaluating the use of adjuvant chemotherapy and radiation therapy in the stage I setting.
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Int. J. Radiat. Oncol. Biol. Phys. · Sep 1999
Comparative StudyIsotope selection for patients undergoing prostate brachytherapy.
Ultrasound-guided transperineal interstitial permanent prostate brachytherapy (TIPPB) is generally performed with either 103Pd or 125I. The use of 125I for low Gleason score tumors and 103Pd for higher Gleason scores has been suggested based on isotope dose rate and cell doubling time observed in in vitro studies. While many centers follow these isotope selection criteria, other centers have elected to use only a single isotope, regardless of Gleason score. No clinical data have been published comparing these isotopes. This study was undertaken to compare outcomes between 125I and 103Pd in a matched pair analysis for patients undergoing prostate brachytherapy. ⋯ This matched pair analysis failed to demonstrate a difference for 125I and 103Pd in PSA-RFS for patients undergoing TIPPB. In addition, there were no observed advantages for either 125I or 103Pd in either the low or high Gleason score groups. This data indicates that the role of isotope selection for patients undergoing TIPPB requires further clarification.
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To demonstrate the technique and feasibility of prostate brachytherapy performed with local anesthesia only. ⋯ The substitution of local anesthesia has facilitated rapid introduction of a high-volume brachytherapy program at an institution that previously had none, without requiring the allocation of significant operating room time. Although the patients reported here were implanted without conscious sedation, we are starting to try various sedatives and analgesics for patients who we anticipate will have substantial anxiety with the procedure.