International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1998
Patterns of failure following treatment for medulloblastoma: is it necessary to treat the entire posterior fossa?
Craniospinal radiation (CSRT) followed by a boost to the entire posterior fossa (PF) is standard postoperative therapy for patients with medulloblastoma. A large proportion of recurrences after treatment are local, with approximately 50-70% of recurrences occurring in the PF. It is unclear, however, whether these failures are occurring in the original tumor bed or outside the tumor bed, but still within the PF. With improved diagnostic imaging, better definition of tumor volumes, and the use of three-dimensional conformal therapy (3D CRT), we may be able to restrict the boost volume to the tumor bed plus a margin without compromising local control. This retrospective study analyzes the patterns of failure within the PF in a series of patients treated with radiation therapy (RT). ⋯ Leptomeningeal failure is a common component of failure and occurs in the leptomeninges of the PF, as well as the spine. Isolated tumor bed failure is a rarely observed event and occurred in only 2 of 27 failures described here. Similarly, parenchymal (nonleptomeningeal) failures in the PF but outside of the tumor bed were rare: 4 patients recurred in this manner, only 1 of whom was an isolated event without other sites of recurrence. Our data suggest that, when the entire PF is treated, very few failures develop in isolation in the PF outside the tumor bed. Further studies will be necessary to determine if RT to the tu
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1998
Clinical TrialPhase I dose escalating trial of hyperfractionated pre-operative chemoradiation for locally advanced rectal cancer.
To determine the acute toxicity, post-operative complications, pathologic response and extent of downstaging to high dose pre-operative radiation using a hyperfractionated radiation boost and concurrent chemotherapy in a prospective Phase I trial. ⋯ This regimen of high dose pre-operative chemoradiation employing a hyperfractionated radiation boost is feasible and tolerable and results in significant downstaging in locally advanced rectal cancer. The vast majority of patients (96%) achieved negative margins, which appears to be a prerequisite for local control (p= 0.04). Older age (> or =61 years) was a significant predictor for improved DFS. This regimen (at dose Level III, 61.8 Gy) is currently being tested in a Phase II setting.
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1998
Prognostic factors derived from recursive partition analysis (RPA) of Radiation Therapy Oncology Group (RTOG) brain metastases trials applied to surgically resected and irradiated brain metastatic cases.
(a) To identify the prognostic factors that determine survival after surgical resection and irradiation of tumors metastatic to brain. (b) To determine if the prognostic factors used in the recursive partition analysis (RPA) of brain metastases cases from Radiation Therapy Oncology Group (RTOG) studies into three distinct survival classes is applicable to surgically resected and irradiated patients. ⋯ Based on the results of this study, the patients and disease characteristics have significant impact on the survival of patients with brain metastases treated with a combination of surgical resection and radiotherapy. These parameters could be used in selecting patients who would benefit most from such treatment.
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1998
The presence of proliferative breast disease with atypia does not significantly influence outcome in early-stage invasive breast cancer treated with conservative surgery and radiation.
To evaluate the influence of the benign background breast-tissue change of atypical hyperplasia (AH) on outcome in patients with early-stage invasive breast cancer treated with conservative surgery and radiation. ⋯ AH was not associated with an increased risk of ipsilateral breast tumor recurrence or contralateral breast cancer in this study of patients with invasive breast cancer treated with conservative surgery and radiation. Therefore, the presence of proliferative changes with atypia in background benign breast tissue should not be a contraindication to breast-conservation therapy.
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1998
A critical evaluation of the planning target volume for 3-D conformal radiotherapy of prostate cancer.
To determine an adequate planning target volume (PTV) margin for three-dimensional conformal radiotherapy (3D CRT) of prostate cancer, the uncertainties in the internal positions of the prostate and seminal vesicles (SV) and in the treatment setups were measured. ⋯ PTV margins of 10 to 16 mm are required to encompass all (99%) possible positions of the prostate or SV during 3D CRT. PTV margins of 7 to 11 mm will encompass the measured uncertainties with a 95% probability. PTV margins of 5 mm may not adequately cover the intended volume.