International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1999
Investigation of hypersensitivity to fractionated low-dose radiation exposure.
Hypersensitivity to cell killing of exponentially growing cells exposed to X-rays and gamma rays has been reported for doses below about 0.5 Gy. The reported results have been interpreted to suggest that a dose of 0.5 Gy or less is not sufficient to trigger an inducible repair mechanism. The purpose of this study was to examine this suggested hypersensitivity after multiple low doses (0.3 Gy) of gamma rays where a) the effect would be expected to be significantly magnified, and b) the effect might be of clinical relevance. ⋯ These experiments were specifically designed to magnify and probe possible clinical implications of proposed "low-dose hypersensitivity" effects, in which significant deviations at low doses from the LQ model have been suggested. In fact, the results at low doses per fraction were consistent with LQ predictions based on higher dose per fraction data. This finding is in agreement with the well-documented utility of the LQ approach in estimating isoeffect doses for alternative fractionation schemes, and for brachytherapy.
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1999
Clinical and dosimetric predictors of radiation-induced esophageal toxicity.
To evaluate the incidence, severity, and clinical/dosimetric predictors of acute and chronic esophageal toxicities in patients with non-small cell lung cancer (NSCLC) treated with high-dose conformal thoracic radiation. ⋯ Late esophageal toxicity following aggressive, high-dose conformal radiotherapy is common but rarely severe. Dosimetric variables addressing the longitudinal and circumferential character of the esophagus have biologic rationale and are predictive of late toxicity. Further studies are needed to assess whether these parameters are better predictors than those derived from traditional DVHs.
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1999
Urinary morbidity following ultrasound-guided transperineal prostate seed implantation.
To assess the urinary morbidity experienced by patients undergoing ultrasound-guided, permanent transperineal seed implantation for adenocarcinoma of the prostate. ⋯ TPIPB is well tolerated but associated with mild to moderate urinary morbidity. Pretreatment prostatic volume and AUA scoring were shown to significantly predict for grade 2 toxicity while the use of preimplant, pelvic XRT and isotope selection did not. Patients undergoing TURP for protracted symptoms following TPIPB did well with a 17% risk of developing stress incontinence. V150 did not help identify patients at risk for urinary morbidity. As transperineal prostate implantation is used more frequently the associated toxicities and the definition of possible pretreatment prognostic factors is necessary to
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1999
Patterns of failure and overall survival in patients with completely resected T3 N0 M0 non-small cell lung cancer.
Previous studies of patients with surgically resected non-small cell lung cancer and chest wall invasion have shown conflicting results with respect to prognosis. Whether high-risk subsets of the T3 N0 M0 population exist with respect to patterns of failure and overall survival has been difficult to ascertain, owing to small numbers of patients in most series. ⋯ Patients with completely resected T3 N0 M0 non-small cell lung cancer have similar local control and overall survival irrespective of primary location, type of surgery performed, or use of adjuvant radiation therapy. Additionally, the tumor recurrence rate and overall survival found in this study support the placement of this group of patients in Stage IIB of the 1997 AJCC lung staging classification.
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Int. J. Radiat. Oncol. Biol. Phys. · Aug 1999
Mature results of a pilot study of pelvic radiotherapy with concurrent continuous infusion intra-arterial 5-FU for stage IIIB-IVA squamous cell carcinoma of the cervix.
To evaluate the long-term results of continuous infusion intra-arterial 5-fluorouracil (CI IA 5-FU) given with concurrent pelvic radiotherapy (RT) for FIGO stage IIIB-IVA carcinoma of the cervix. ⋯ While this series is small, the fact that 4 patients with massive Stage IIIB tumors survived after a total radiation dose of only 50 Gy suggests that RT with CI IA 5-FU deserves further study. Modifications in dose, technique, and route of administration should reduce toxicity, and the addition of intracavitary RT should improve the local effectiveness of combined treatment.