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
Dose escalation of chart in non-small cell lung cancer: is three-dimensional conformal radiation therapy really necessary?
To evaluate, preclinically, the potential for dose escalation of continuous, hyperfractionated, accelerated radiation therapy (CHART) for non small-cell lung cancer (NSCLC), we examined the strategy of omission of elective nodal irradiation with and without the application of three-dimensional conformal radiation technology (3DCRT). ⋯ 3DCRT is fundamental to achieving optimal PTV coverage in NSCLC. A policy of omission of elective nodal irradiation alone (and using 2D technology) will not achieve optimal PTV coverage or dose escalation. 3DCRT with omission of ENI can achieve true escalation of CHART in 55.5% of tumors, depending on their site and N-stage.
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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
Clinical dose-volume histogram analysis for pneumonitis after 3D treatment for non-small cell lung cancer (NSCLC)
To identify a clinically relevant and available parameter upon which to identify non-small cell lung cancer (NSCLC) patients at risk for pneumonitis when treated with three-dimensional (3D) radiation therapy. ⋯ The V20 from the total lung DVH is a useful parameter easily obtained from most 3D treatment planning systems. The V20 may be useful in comparing competing treatment plans to evaluate the risk of pneumonitis for our individual patient treatment and may also be a useful parameter upon which to stratify patients or prospective dose escalation trials.
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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.