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Biomedical subjects

L W Davis

Publications and source records attributed to L W Davis.

At least 73 records · Page 4Linked to original sources

Randomized preoperative and postoperative radiation therapy for patients with carcinoma of the head and neck: preliminary report.

Two hundred and ninety-eight patients with squamous cell carcinoma of the oral cavity, oropharynx, supraglottic larynx, hypopharynx or maxillary sinus have been randomized for preoperative radiation therapy and surgery vs. surgery and postoperative radiation therapy plus, in the case of patients with lesions of the oral cavity and oropharynx, radical radiation therapy. Data have been analyzed on 243 patients in this interim report. The differences between the three groups with respect to local control and survival are not statistically significant at this time. Additional accrual and continued follow-up are necessary to make definite treatment comparisons.

Carcinoma, Squamous Cell↗

Evaluation of carcinoma of the uterine cervix before radiotherapy.

In 1974 the Patterns of Care Study began a prospective nationwide survey of radiotherapeutic cancer care in the United States. Cancer of the uterine cervix was one of the diseases surveyed. Pretreatment evaluation data were collected from 170 randomly chosen radiation therapy facilities. The frequency of use of tests in workup varied substantially according, for example, to the severity of disease and the availability of tests. For carcinoma of the uterine cervix, we found that the following tests were used routinely: physical examination, including taking a history; complete blood cell count; serum chemistry analysis; chest roentgenogram; and intravenous pyelogram. Frequent but not routine tests included dilation and curettage and evaluation of the involvement of the bladder and rectum. Other test were used infrequently.

Dilatation and Curettage↗

Measuring the quality of medical care: a beginning.

Quality of medical care is fundamental; however, the recognition of quality is a complex task. The Patterns of Care Study is examining radiotherapeutic care in cancer throughout the United States, using a new methodology which can be applied to other medical disciplines. The system is described and illustrated as applied to the management of carcinoma of the cervix. Considerable variations in treatment have been identified. These variations can be studied and, where necessary, modified by appropriate educational programs; thus, the quality of medical care can be improved.

Decision Making↗

The Radiation Therapy Oncology Group: a progress report.

The Radiation Therapy Oncology Group (RTOG), founded in 1971, comprises 35 university hospitals which are participating in 21 active protocols, four registries and eight pilot studies, including Phase I/II studies. Case accession has grown to over 1000 in 1977 with 19,801 patients being entered in the RTOG initial registration. Goals of the RTOG include: advancing knowledge of the role of radiation therapy in disease management; improving control of primary and regional disease; reducing morbidity and complications from treatment; and collaborating with other oncology disciplines to obtain data on multimodality therapy.

Clinical Trials as Topic↗

The association of the IGA levels of serum and whole saliva with the progression of oral cancer.

Elevated IgA concentrations in the serum and whole saliva of patients with neoplastic disease have been reported. However, there does not seem to be any information available on the correlation of the secretory immunoglobulins of these patients with the progress of their disease. The whole saliva and sera of 102 cases of squamous carcinoma of the oral mucosa were studied. Patients were subclassified into age-matched groups of primary untreated cancer (21), recurrent cancer (18), and "cured" patients who had been free of disease for at least 9 months (16). A separate group of laryngeal (14) patients was included. Sixteen (16) patients treated by radiation therapy alone were also included to test the effects of radiation on whole saliva IgA. An age-matched group of patients (17) with moderate to severe periodontal disease served as controls. Unstimulated whole saliva was collected for 15 minutes and stored at 0 degrees C. IgA was quantitated by radial immunodiffusion on Hyland and Meloy Laboratory low level plates with 7S and 11S standards. Serum IgA was measured on Hyland plates with serum standards. Protein content of saliva was assayed by the Lowry method. Flow rate was quantitated for the 15-minute collection period. Primary oral and laryngeal cancer patients had a two-fold increase of serum and salivary IgA compared to controls. Recurrent cancer patients had even greater elevation of salivary IgA. Cured patients showed a persistent elevation of serum but a return to normal of salivary IgA. Radiation therapy did not markedly influence the level of salivary IgA. A followup study of 26 patients confirmed this pattern of a drop in whole salivary IgA with cure and a spike with recurrence. It would appear that IgA levels of whole saliva and serum are elevated in oral cancer patients, and that salivary IgA levels may prove useful in distinguishing patients with possible recurrent disease.

Adult↗

Computer generated isodose curves for high energy x-ray machines. Experimental verification and time-saving strategies.

Calculation of isodose patterns for high energy therapy units using Cunningham's BEAM program requires accurate information on the beam profile in air. This may be obtained by scanning across the x-ray beam using a very small silicon diode detector. Data obtained on a particular unit may not be applicable to any other unit. Computer calculations of isodose curves for high energy x-ray machines must use a 0.25 cm. or smaller lateral grid of dose calculation points to ensure accurate reproduction of the sharp fall-off of the dose at the beam edge. Computer calculation time to obtain the isodose curves using this size lateral grid is prohibitively long. The computing time can be appreciably reduced by: (1) changing the width of the annular sectors used in calculating the contribution of scattered radiation to the dose to 0.5 cm.; and (2) calculating the dose at 0.25 cm. lateral intervals within 1 cm. of the beam edge, but changing the spacing of the grid to 1 cm. inside the field. These programming strategies do not produce any significant change in the isodose curves but lead to a significant reduction in computer time.

Computers↗