PubMed Health⌕ Search

Biomedical subjects

B D Kavanagh

Publications and source records attributed to B D Kavanagh.

27 records · Page 2Linked to original sources
PubMed1997

A pilot study of concomitant boost accelerated superfractionated radiotherapy for stage III cancer of the uterine cervix.

PURPOSE: Retrospective studies suggest that prolonged treatment time adversely affects control rates of squamous carcinomas managed by radiotherapy. From 1989 to 1994 a prospective clinical trial was conducted to assess the feasibility and efficacy of concomitant boost accelerated superfractionated (CBASF) radiotherapy for advanced uterine cervical carcinoma. METHODS AND MATERIALS: Twenty newly diagnosed patients with FIGO stage III squamous cell carcinoma of the cervix were irradiated using a CBASF regimen. Patients received 45 Gy administered to the whole pelvis in 25 fractions in 5 weeks. On Monday, Wednesday, and Friday of the last 3 weeks, an additional 1.6 Gy boost was given 6 hours after the whole pelvis treatment. The 9 boost treatments, totaling 14.4 Gy, were given via lateral fields encompassing the parametria and primary tumor for a cumulative tumor dose of 59.4 Gy. A single low-dose rate brachytherapy procedure was performed within 1 week after the external beam radiotherapy to raise the point A dose to 85-90 Gy in 42 days. Primary endpoints of analysis were local control, complications, and patterns of failure. Results are compared with the outcomes of 21 patients treated with conventionally fractionated (CF) radiotherapy during the same years. RESULTS: Median total treatment time was 46 days in the CBASF group (range 37-62). Median follow-up interval among surviving CBASF patients is 3.8 years. The four-year actuarial local control rates are 78% and 70% in the CBASF and CF groups, respectively (p = ns). Only 2 CBASF patients required a treatment break because of acute toxicity, but severe late complications occurred in 8/20 CBASF patients for a crude rate of 40%. Distant failure was more common than local failure in the CBASF group, and para-aortic node failure occurred in six of the eight CBASF patients with distant failure. CONCLUSIONS: In the management of stage III cervix cancer, the CBASF regimen produced a trend toward improved local control when compared with the CF regimen, shifting the patterns of failure toward a higher rate of isolated distant failures. The high frequency of para-aortic node failure warrants consideration of elective treatment to this region in stage III patients treated with curative intent. Although the high local control rate of the CBASF regimen supports further investigation of accelerated treatment regimens for locally advanced cervix cancer, the unacceptable risk of late complications necessitates refinement in technique and scheduling to improve the therapeutic ratio.

Adult↗
PubMed1997

A retrospective quality of life analysis using the Lung Cancer Symptom Scale in patients treated with palliative radiotherapy for advanced nonsmall cell lung cancer.

PURPOSE: To measure symptom palliation in patients treated with radiation therapy for advanced nonsmall cell lung cancer (NSCLC). METHODS AND MATERIALS: Five hundred thirty patients with NSCLC were treated at the Medical College of Virginia between 1988 and 1993. Sixty-three patients with the least favorable prognostic features received palliative radiation to 30 Gy in 10 or 12 fractions for symptoms related to the presence of intrathoracic tumor. The observer portion of the Lung Cancer Symptom Scale (LCSS) was employed in a retrospective chart review, scoring measures of appetite, fatigue, cough, dyspnea, hemoptysis, and pain. RESULTS: In 54 evaluable patients, median survival was 4 months and was independent of age, stage, performance status, or histology. Ninety-six percent of the patients had at least one LCSS symptom at presentation. Fatigue was unaffected by therapy. Improvements in appetite (p = 0.68) and pain (p = 0.61) were not statistically significant. There was, however, a statistically significant reduction in cough (p = 0.01), hemoptysis (p = 0.001), and dyspnea (p = 0.0003). Self-limiting acute side effects included transient esophagitis in 37% of patients, though no severe toxicities were noted. CONCLUSIONS: These results suggest symptomatic benefit from radiotherapy even in those NSCLC patients with advanced disease and a limited life expectancy. Treatment should be given to patients whose symptoms are most amenable to palliation. A site-specific quality of life instrument such as the LCSS should be included within any future clinical trial of NSCLC management so that symptom control may be scored as a treatment outcome in addition to disease-free survival.

Aged↗
PubMed1995

Clinical use of a digital simulator for rapid setup verification in high dose rate brachytherapy.

PURPOSE: Fractionated high dose rate (HDR) brachytherapy provides a number of technical advantages over conventional implant therapy in that (a) it can be carried out on an outpatient basis, (b) personnel exposure is reduced to insignificant levels, and (c) patient motion during irradiation is minimized, resulting in a more accurate delivery of the planned radiation dose distribution to the target and critical structures. The patient discomfort associated with the repeated applicator insertions and/or treatment setups can be alleviated to the extent that the setup time is held to a minimum. This work describes the use of a prototype digital simulator to obtain fast, high-quality digital images for rapid setup verification. METHODS AND MATERIALS: The digital imaging system of the prototype simulator consists of a charge-coupled device (CCD) camera, which views the x-ray image optically transmitted from a conventional phosphor screen. Treatment is carried out with a remote afterloading HDR unit immediately after setup verification with the patient on the simulator stretcher. The high-resolution digital images are processed and displayed in about 5 s, as opposed to a minimum of approximately 2 min for film. RESULTS: The imaging system has been evaluated for a variety of implant types, both intracavitary and interstitial. The digital radiographs provided permanent high-resolution images as required in most cases for precise applicator positioning. The gray scale manipulation capabilities were found to be useful for imaging in regions of different density, such as lung and soft tissue, in the same radiograph. The advantages of short image acquisition and display times were observed in all cases, but were most evident in the intraluminal procedures, which sometimes involved several pretreatment applicator adjustments at a time of considerable patient discomfort. CONCLUSION: Pretreatment imaging is necessary to fully exploit the technical advantages of HDR brachytherapy. High-quality digital radiography offers unique advantages in HDR setup and verification by providing fast high-resolution, undistorted images with software manipulation capabilities and permanent storage of images.

Brachytherapy↗
PubMed1995

Radiation-induced enhanced proliferation of human squamous cancer cells in vitro: a release from inhibition by epidermal growth factor.

Ionizing radiation is believed to stimulate the repopulation of squamous carcinoma cells that survive the early portion of a fractionated course of radiotherapy. To characterize any intrinsic radiation-induced adaptive response and to examine whether epidermal growth factor (EGF) influences this response, A431 and 183A cells were irradiated with repeated daily exposures of 0.5-0.75 Gy and then grown in monolayer culture for 7 days with or without EGF at a 1 ng/ml concentration. Cell numbers were quantified using a microtiter dye-reduction assay. EGF alone caused approximately 70% and 30% growth inhibition of human SC A431 and 183A cells, respectively. Although radiation alone did not affect proliferative rates in these conditions, radiation eliminated the EGF-related growth inhibition in both cell lines. This effect was dose dependent in single radiation exposure experiments. Cell cycle analyses indicated that EGF initially promoted entry into S-phase 3 days after treatment but caused a G1-S block after 7 days. Treatment with radiation recruited cells into S-phase and G2-M, an effect which was sustained 7 days after treatment, overriding the influence of EGF. Radiation-induced modulation of the response of human squamous carcinoma cells to EGF in vitro after single and repeated radiation exposures suggests a proliferation response that may underlie enhanced repopulation of tumor clonogens in vivo.

Carcinoma, Squamous Cell↗
PubMed1993

The effect of flunarizine on erythrocyte suspension viscosity under conditions of extreme hypoxia, low pH, and lactate treatment.

Flunarizine is a class IV calcium channel blocker which increases oxygen delivery to hypoxic regions in solid tumours, exerting a radiosensitising effect in vivo in animal tumour models. Precisely how the drug improves oxygenation is not well understood. We hypothesised that metabolic conditions present within solid tumours reduce red blood cell (RBC) deformability and that flunarizine exerts its in vivo effect by preventing this loss of RBC deformability. A microrheometer was used to compare the viscosity of rat and human RBC suspensions in conditions of hypoxia (pO2 < 10 mmHg), acidic environment (pH 6.8), and elevated lactate concentration (lactate 5 mMol l-1), without or with flunarizine at concentrations of 5, 10, and 50 mg l-1. The effects of flunarizine on RBC density and morphology were also recorded. Hypoxia, low pH, and lactate exposure together increased both human and rat RBC suspension viscosity. Flunarizine at concentrations of 5 and 10 mg l-1 prevented the increases in viscosity. The drug caused dose-dependent shifts toward lower cell density while inducing a characteristic cupped shape (stomatcytic morphology), suggesting a mechanism involving calmodulin inhibition. The results support the hypothesis that flunarizine improves tumour blood flow and oxygenation by enhancing flow properties of RBC's in solid tumours.

Animals↗
PubMed1992

Syndrome of inappropriate secretion of antidiuretic hormone in a patient with carcinoma of the nasopharynx.

A patient with a primary undifferentiated carcinoma of the nasopharynx manifested the clinical syndrome of inappropriate antidiuretic hormone secretion (SIADH). Immunohistochemical techniques demonstrated the presence of vasopressin, neurophysin, and their precursor (propressophysin) in the cancer cells. In situ hybridization additionally confirmed the expression of propressophysin messenger RNA in these cells. To the knowledge of the authors, this represents not only the first case of SIADH caused by carcinoma of the nasopharynx, but also the first report of pathologic confirmation of the syndrome with the use of both molecular and immunologic probes.

Arginine Vasopressin↗