PURPOSE: Erythema multiforme and Stevens-Johnson syndrome have been associated with anticonvulsant medications (AEDs) in patients with brain tumors receiving cranial irradiation. AEDs are also known to cause mild drug rashes. The incidence of these complications has not been well studied among patients with brain tumors. We reviewed the records of patients with brain tumors treated with cranial radiation and AEDs to assess the frequency of both severe and mild skin reactions. METHODS: Retrospective review of 289 radiotherapy records of consecutively treated patients from 1988 to 1993. RESULTS: Only one of 289 patients developed erythema multiforme. Milder rashes, however, occurred in 18% of exposures to AEDs including 22% of exposures to phenytoin, compared with the expected rate of 5-10%. Most of the mild drug rashes occurred before the initiation of radiotherapy, suggesting that radiation was not the cause of these reactions. CONCLUSIONS: Severe skin rashes are rare among patients with brain tumors receiving radiation therapy and AEDs. There is, however, an increased frequency of mild drug rashes among patients with brain tumors that does not appear related to radiation. 相似文献
Total radiation dose often can be increased without subsequent increases in the severity of tissue injury by using reduced doses per fraction. The flexure dose, df, is defined as the largest fractional dose for which further fractionation produces no significant change in the total dose required to reach a specified effect level. Thus, df is clinically relevant in that it represents the limit of effective dose fractionation. For those tissues in which injury reflects depletion of a critical proportion of target cells, the flexure dose is a measure of the extent of the initial, nearly linear portion of the dose-survival curve. More generally, the flexure dose is a measure of the extent of the initial, nearly linear portion of a dose-response curve in organized tissue, whatever its relationship to clonogenic target cells might be. Several quantitative expressions for df are derived. The characteristic common to these is that each defines the flexure dose as a multiple of the ratio alpha/beta of the parameters of the linear-quadratic model of cell survival or dose response, where the multiple is a measure of experimental or statistical resolution. These multiples tend to fall within a limited range, thereby defining the "region of flexure" via the inequality 0.05 (alpha/beta) less than or equal to df less than or equal to 0.15 (alpha/beta). Estimates of the region of flexure are presented for a variety of normal and neoplastic tissues. 相似文献
Digital data from 3‐D treatment planning computers is generally used for patient planning and then never considered again. However, such data contains enormous quantities of information regarding patient geometries, tissue outlining, treatment approaches and dose distributions. Were such data accessible from planning systems from multiple manufacturers, there would be substantial opportunities for undertaking quality assurance of radiotherapy clinical trials, prospective assessment of trial outcomes and basic treatment planning research and development. The technicalities of data exchange between planning systems are outlined, and previous attempts at producing systems capable of viewing and/or manipulating imaging and radiotherapy digital data reviewed. Development of a software system for enhancing the quality of Australasian clinical trials is proposed. 相似文献
Since the first treatment of acoustic neurinoma using the γ-knife by Leksell, a series of cases have been reported with good control rates. However, the most frequent complication is delayed hearing loss which occurs in more than 50% of patients. The purpose of this study was to define a safe dose by analyzing the radiosurgical dose-response relationship and histological effects on the normal cochlear nerve in rabbit. The rabbits had computed tomography (CT)-guided stereotactic radiosurgery on their cochlear nerves in the internal auditory canal with a 4 mm collimator focusing of a γ-unit. Maximum doses of 10, 20, 30, 40, 60, 80, 100, 200 and 500 Gy were administered. After the radiosurgery, auditory brain stem responses (ABR) and the behavior of the rabbits were evaluated periodically. At the conclusion, histological investigations were performed. No physiological or histological findings were observed from doses of 30 Gy or below during the 12 month period after the radiosurgery. A dose of 100 Gy caused a severe ABR threshold elevation, vestibular dysfunction and facial palsy. Necrosis and demyelination of nerves were observed pathologically. In this study, we determined that the safe dose to the normal cochlear nerve during radiosurgery was under 40 Gy in rabbits, and complications seemed to vary due to individual differences in radiation tolerance. 相似文献
The aim of the present study was to investigate whether cisplatin would enhance the radioresponse of a human tumour xenograft
when given in different schedules combined with accelerated fractionated radiation therapy. A human squamous carcinoma of
the hypopharynx, FaDu, was grown in the thigh of athymic nude mice. Tumours were exposed to twice-daily 2-Gy fractions, applied
6 h apart over 2 weeks, 5 days a week, alone or combined with cisplatin given at maximally tolerated doses in three different
schedules: (1) i.p. as a single bolus (SB) or (2) i.p. as a daily bolus at 30 min before the first daily radiation fraction
or (3) s.c. as a continuous infusion through a mini-osmotic pump over 13 days, commencing 24 h prior to the first daily radiation
fraction. The end point for the study was tumour growth delay (TGD), calculated as the difference between the delay in regrowth
to 200% of the initial tumour size in treated versus control mice. SB cisplatin plus radiation showed only an additive effect
on TGD, whereas daily-bolus and continuous-infusion cisplatin demonstrated a greater than additive effect when combined with
accelerated fractionated radiation in this human tumour model. Cisplatin appears to be especially beneficial as a radiation
enhancer when given throughout the course of radiation.
Received: 15 December 1996 / Accepted: 25 March 1997 相似文献
Objective: To assess the risk of neoplastic development among persons exposed to scalp irradiation. Study Design: Historical cohort study initially; prospective follow-up subsequently. Method: Two control groups—population and siblings—matched for age, sex, ethnic origin, and year of immigration. Follow-up from time of irradiation (1950s) until the end of 1991. Linkage with nationwide cancer registry. Results: A 4.5–fold incidence of cancer (P < .01) and a 2.6–fold increase of benign tumors were noted. The mean length of latency period until tumor development was 11 years for malignant tumors and 21.5 years for benign. A clear dose response effect for both cancer and benign tumors was demonstrated. Conclusions: The study confirms the role of radiation in salivary gland carcinogenesis. It indicates a need for better awareness, a comprehensive examination, and long-term follow-up of patients who have been subjected to head and neck radiation. 相似文献
Purpose: The aim of our study was to determine if paclitaxel could be used as a radiosensitizer in vivo.
Materials and methods: Paclitaxel was tested as a single agent and combined with an X-ray treatment. Paclitaxel was administered i.p. in doses from 30 to 120 mg/kg b.w. to (C3D2F1) mice bearing spontaneous mammary carcinoma. Tumor growth delay (TGD) or tumor control dose (TCD50, radiation dose needed to induce local tumor control in 50% of irradiated animals) and moist desquamation dose (MDD50, radiation dose needed to induce serious moist desquamation in 50% of the non-tumor-bearing feet) were the endpoints. DNA flow cytometric analysis was performed.
Results: DNA analysis demonstrated a G2/M block of tumor cells and a depletion of cells in S phase, with a maximum at 24 h from paclitaxel administration. Administering paclitaxel, in graded doses, 15 min before a 10-Gy X-ray treatment resulted in a linear regression line, almost parallel to that with paclitaxel alone, with a growth delay of about 6 days. In contrast, varying the X-ray dose with a constant paclitaxel injection (45 mg/kg b.w.) treatment showed some degree of synergism as the linear regression curves diverged. Interval time and sequence between paclitaxel administration and a 10 Gy X-ray treatment did not influence TGD. Protocols with paclitaxel at 30, 45, or 60 mg/kg were combined with radiation treatments at various doses (from 10 to 65 Gy). Values of TCD50 varied from 50.8 Gy for X-ray alone to 31.8 Gy for paclitaxel 60 mg/kg + X-ray. No differences were observed among MDD of different protocols.
Conclusions: These results suggest that, under some conditions, paclitaxel combined with radiation can show superadditive effects and this result combined with the lack of severe normal tissue damage indicate that a favorable therapeutic gain can be obtained. 相似文献
Purpose: To evaluate the outcome of patients with extra-mesenteric desmoid tumors treated with radiation therapy, with or without surgery.
Methods and Materials: The outcome for 75 patients receiving radiation for desmoid tumor with or without complete gross resection between 1965 and 1994 was retrospectively reviewed utilizing univariate and multivariate statistical methods.
Results: With a median follow-up of 7.5 years, the overall freedom from relapse was 78% and 75% at 5 and 10 years, respectively. Of the total, 23 patients received radiation for gross disease because it was not resectable. Of these 23 patients, 7 sustained local recurrence, yielding a 31% actuarial relapse rate at 5 years. Radiation dose was the only significant determinant of disease control in this group. A dose of 50 Gy was associated with a 60% relapse rate, whereas higher doses yielded a 23% relapse rate (p < 0.05). The other 52 patients received radiation in conjunction with gross total resection of tumor. The 5- and 10-year relapse rates were 18% and 23%, respectively. No factor correlated significantly with disease outcome. There was no evidence that radiation doses exceeding 50 Gy improved outcome. Positive resection margins were not significantly deleterious in this group of irradiated patients. For all 75 patients, there was no evidence that radiation margins exceeding 5 cm beyond the tumor or surgical field improved local-regional control. Ultimately, 72 of the 75 patients were rendered disease-free, but 3 required extensive surgery (amputation, hemipelvectomy) to achieve this status. Significant radiation complications were seen in 13 patients. Radiation dose correlated with the incidence of complications. Doses of 56 Gy or less produced a 5% 15-year complication rate, compared to a 30% incidence with higher doses (p < 0.05).
Conclusions: Radiation is an effective modality for desmoid tumors, either alone or as an adjuvant to resection. For patients with negative resection margins, postoperative radiation is not recommended. Patients with positive margins should almost always receive 50 Gy of postoperative radiation. Unresectable tumors should be irradiated to a dose of approximately 56 Gy, with a 75% expectation of local control. 相似文献