International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · May 1996
Lateral rectal shielding reduces late rectal morbidity following high dose three-dimensional conformal radiation therapy for clinically localized prostate cancer: further evidence for a significant dose effect.
Using conventional treatment methods for the treatment of clinically localized prostate cancer central axis doses must be limited to 65-70 Gray (Gy) to prevent significant damage to nearby normal tissues. A fundamental hypothesis of three-dimensional conformal radiation therapy (3DCRT) is that, by defining the target organ(s) accurately in three dimensions, it is possible to deliver higher doses to the target without a significant increase in normal tissue complications. This study examines whether this hypothesis holds true and whether a simple modification of treatment technique can reduce the incidence of late rectal morbidity in patients with prostate cancer treated with 3DCRT to minimum planning target volume (PTV) doses of 71-75 Gy. ⋯ The incidence of late rectal morbidity with 3DCRT to minimum PTV doses of 71-75 Gy is acceptable and to date no Grade 4-5 rectal morbidities have been observed. In our experience, higher doses to the center of the prostate are associated with an increased likelihood of developing Grade 2-3 rectal morbidity but treatment techniques that reduce the total dose to the anterior rectal wall have reduced the incidence of late rectal morbidity. If clinical studies indicate improved tumor control with minimum PTV doses above 71 Gy, then dose escalation above 76 Gy to the center of the prostate should be pursued cautiously with treatment techniques that limit the total dose to the anterior rectal wall.
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Int. J. Radiat. Oncol. Biol. Phys. · May 1996
Analysis of localization errors in the definition of the mantle field using a beam's eye view treatment-planning system.
Reports of the treatment of Hodgkin's disease (HD) with radiotherapy using the mantle field technique have demonstrated that coverage of disease by the field blocks significantly compromises outcome. It is our hypothesis that the availability of computerized tomography images reduces the incidence of localization error, and that the use of beam's eye view treatment planning techniques may further improve localization. The purpose of this report is to assess the possible contribution of a three-dimensional treatment-planning system to tumor localization and mantle block drawing in patients with HD. ⋯ The availability of CT imaging offers an advantage in the outlining of the mantle field in the treatment of Hodgkin's disease. When the error rate is evaluated using a beam's eye view treatment planning system, a significant proportion of tumors may be overlapped by the outlined mantle blocks even when CT images are available for reference. The use of beam's eye view treatment planning in mantle field definition, especially for tumors in the axillary region, may reduce the incidence of geographic misses.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 1996
Multicenter StudyA multiinstitutional outcome and prognostic factor analysis of radiosurgery for resectable single brain metastasis.
Recent randomized trials of selected patients with single brain metastasis comparing resection followed by whole-brain radiotherapy (WBRT) to WBRT alone have shown a statistically significant survival advantage for surgery and WBRT. A multiinstitutional retrospective study was performed, which identified comparable patients who were treated with stereotactic radiosurgery (RS) and WBRT. ⋯ The RS in conjunction with WBRT for single brain metastasis can produce substantial functional survival, especially in patients with good performance status and without extracranial metastasis. These results are comparable to recent randomized trials of resection and WBRT. The advantages of RS over surgery in terms of cost, hospitalization, morbidity, and wider applicability strongly suggest that a randomized trial to compare RS with surgery is warranted.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 1996
External beam radiation for retinoblastoma: results, patterns of failure, and a proposal for treatment guidelines.
To analyze treatment results and patterns of failure following external beam radiation for retinoblastoma and propose treatment guidelines according to specific clinical variables. ⋯ 1) We find that external beam radiation to a dose of 45 Gy in fractions of 1.5 to 2.0 Gy provides adequate tumor control in retinoblastoma eyes Groups I-II (Reese-Ellsworth classification) or tumors measuring 15 mm in diameter or less. Eyes in more advanced group staging or containing tumors larger than the 15 mm seem to require higher radiation doses. We propose treatment guidelines for external beam radiation of retinoblastoma that specifically take into account the important clinical variables of tumor stage and patient age. 2) External beam radiation does not prevent the appearance of new tumors in clinically uninvolved retina. Therefore, the traditional belief that external beam radiation can treat the retina "prophylactically" should be seriously questioned. Due to this finding and their significant less morbidity, focal treatment modalities (plaque brachytherapy, photocoagulation, and/or cryotherapy), when clinically feasible, should be considered the treatment of choice for intraocular retinoblastoma. External beam radiation should be considered only when focal treatment modalities are not clinically indicated.
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Int. J. Radiat. Oncol. Biol. Phys. · Apr 1996
Clinical Trial Controlled Clinical TrialEarly evaluation of abdominal/hepatic irradiation and 5-fluorouracil/leucovorin infusion after pancreaticoduodenectomy.
To describe the toxicities of a combined modality adjuvant regimen for patients with resectable periampullary adenocarcinoma. ⋯ These data indicate that adjuvant therapy with concomitant large-field radiation and infusional chemotherapy is feasible and associated with mangeable toxicities in patients undergoing pancreaticoduodenectomy for periampullary adenocarcinoma. Improvement in survival over other adjuvant regimens has not thus far been observed. Modification of this strategy may be required.