International journal of radiation oncology, biology, physics
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 1999
Normal tissue complication probabilities correlated with late effects in the rectum after prostate conformal radiotherapy.
Radiation therapy of deep-sited tumours will always result in normal tissue doses to some extent. The aim of this study was to calculate different risk estimates of late effects in the rectum for a group of cancer prostate patients treated with conformal radiation therapy (CRT) and correlate these estimates with the occurrences of late effects. Since the rectum is a hollow organ, several ways of generating dose-volume distributions over the organ are possible, and we wanted to investigate two of them. ⋯ 1) High-dose levels corresponding to small volume fractions of the cumulative dose-volume histograms were best correlated with the occurrences of late effects in the rectum as measured with questionnaires. This is compatible with a more serial organisation of the rectal tissue architecture than previously reported. 2) Reducing the Lyman-Kutcher model's volume parameter, thus allowing small high-dose regions to determine the NTCP, improved the correlation, but not beyond that of high-dose levels corresponding to small volume fractions of the cumulative dose-volume histograms.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 1999
Local recurrences and distant metastases after breast-conserving surgery and radiation therapy for early breast cancer.
To identify predicting factors for local failure and increased risk of distant metastases by statistical analysis of the data after breast-conserving treatment for early breast cancer. ⋯ First events included 44 isolated local recurrences, 8 isolated axillary node recurrences, 44 isolated distant metastases, 1 local recurrence with synchronous axillary node recurrence, 7 local recurrences with synchronous metastases, and 2 local recurrences with synchronous axillary node recurrences and distant metastases. Of 39 pathologically evaluable local recurrences, 33 were classified as true local recurrences and 6 as ipsilateral new primary carcinomas. Seventy patients died (47 of breast carcinoma, 4 of other neoplastic diseases, 10 of other diseases and 9 of unknown causes). The 5- and 10-year rates were, respectively: specific survival 93% and 86%, disease-free survival 85% and 75%, distant metastasis 8.5% and 14%, and local recurrence 7% and 14%. Mean intervals from the beginning of treatment for local recurrence or distant metastases were, respectively, 60+/-6 months (median: 47 months, range: 6-217 months) and 49.5+/-5.4 months (median: 33 months, range: 6-217 months). After local recurrence, salvage mastectomy was performed in 46 patients (85%) and systemic hormonal therapy and/or chemotherapy was administered to 43 patients. The 5-year specific survival rate after treatment for local recurrence was 78+/-8.2%. Multivariate analysis (multivariate generalization of the proportional hazards model) showed that the probability of local control was decreased by the following four independent factors: young age (< or = 40 yr vs. >40 yr; relative risk [RR]: 3.15, 95% confidence interval [CI]: 1.7-5.8, p = 0.0002), premenopausal status (pre vs. post; RR: 2.9, 95% CI: 1.4-6, p = 0.0048), bifocality (uni- vs. bifocal; RR: 2.7, 95% CI: 2.6-2.8,p = 0.018), and extensive intraductal component (IC <25% vs. IC > or = 25%; RR: 2.6, 95% CI: 13-5.2, p = 0
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 1999
Pulsed low dose rate brachytherapy for uterine cervix carcinoma.
To analyze the outcome and complication rates for patients treated with curative-intent pulsed low dose rate (PLDR) brachytherapy and external beam radiation therapy (EBRT) for uterine cervical carcinoma. ⋯ PLDR brachytherapy is a safe and effective brachytherapy method in the treatment of cervix carcinoma. It combines the physics benefits of dose optimization and the radiobiologic advantages of low dose rate brachytherapy. It eliminates radiation exposure to staff and visitors as well as the need for a source inventory. Although further follow-up will be required, it appears to provide outcome which compares favorably to other methods of brachytherapy delivery, and results in a low rate of complications.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 1999
Clinical TrialConcurrent twice-a-week docetaxel and radiotherapy: a dose escalation trial with immunological toxicity evaluation.
In vitro studies show that docetaxel (Taxotere) is potent radiosensitizer. In a previous study we observed a 27% complete response rate after radiotherapy and weekly docetaxel for non-small-cell lung cancer. In this dose escalation study we investigated the feasibility of a twice-a-week docetaxel regimen together with conventionally fractionated radiotherapy for brain, chest, and pelvic tumors. ⋯ Docetaxel radiochemotherapy is a promising therapeutic approach for locally advanced cancer. The recommended dose of docetaxel for chest and pelvic cancer patients is 15 mg/m2 twice a week. Patients with brain tumors can be safely treated with higher doses of docetaxel (23 mg/m2 twice a week) without toxicity. The severe immunologic toxicity observed suggests that granulocyte-macrophage colony-stimulating factor (GM-CSF) and immunoglobulin administration may be important in the efficacy and tolerance of taxane-based radiochemotherapy. Randomized trials are required to assess whether the efficacy of docetaxel radiochemotherapy depends on the frequency of docetaxel administration during radiation treatment.
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Int. J. Radiat. Oncol. Biol. Phys. · Jan 1999
Modeling late effects in hypofractionated stereotactic radiotherapy.
To investigate the effect of increasing fraction size on cell survival in late responding normal tissues. The hypothesis is that total dose can be reduced for constant tumor cell kill and there will be consequent advantage for some surrounding normal tissue cells. Also, the volume of normal tissue that can potentially be damaged by increasing fraction size is minimized by a high degree of dose conformation achievable in stereotactic radiotherapy (SRT). ⋯ Hypofractionation may be biologically sound when a small volume of normal tissue is covered by high isodose levels. There is a calculated advantage in using larger fractions in terms of cell survival at low isodose levels.