Biomedical subjects

R K Davis

Publications and source records attributed to R K Davis.

At least 37 records · Page 2Linked to original sources

PubMed1990

Thyroid cancer: a computer-assisted review of 5287 cases.

Retrospective computer analysis of all reportable cases of thyroid cancer for the Rocky Mountain Cancer Data Systems between 1973 and 1983 was undertaken. Follow-up data were available for periods of 5 to 10 years. All major histologic findings are reviewed with regard to distribution, prognostic factors, mortality rates, and some treatment modalities. Interesting observations determined by this study include: (1) the significantly greater mortality rates seen in patients with thyroid cancer after 50 years; (2) the lack of increased mortality rates in young patients with differentiated cancer; (3) the poorer prognosis of male patients of equivalent age to female patients in all histologic types of cancer in the first 5 years; (4) the lack of sexual difference in influencing mortality rates after the first 5 years in differentiated cancers and lack of sex as a prognostic indicator in undifferentiated cancers; (5) the excellent prognosis of patients with localized differentiated and medullary cancers and a better-than-expected prognosis in the undifferentiated group; (6) the clear need for combined therapy (surgery and irradiation) in regional medullary cancer; (7) the observation that localized thyroid lymphoma had a higher mortality rate than had regional thyroid lymphoma; and (8) a significantly higher mortality rate in patients older than 79 years with differentiated cancer.

Adenocarcinoma↗

PubMed1990

Unilateral parathyroidectomy: the role of thallium-technetium subtraction scans.

The rationale for using the thallium-technetium subtraction scan as a preoperative localizing study in previously untreated patients with primary hyperparathyroidism is presented. The concept of unilateral parathyroidectomy is also presented, and the role of preoperative localizing studies in this approach to parathyroid surgery is carefully analyzed.

Adenoma↗

PubMed1990

Thermochemotherapy in inoperable head and neck cancer.

A combined hyperthermia and chemotherapy approach was used to treat five patients with locally advanced or recurrent squamous cell carcinoma of the head and neck whose tumors had failed to respond to chemotherapy. In two patients, tumor had recurred after initial combined modality therapy (surgery/radiation) and had failed to respond to one course of cisplatin/5-fluorouracil (cisplatin/5-FU) chemotherapy. The three remaining patients were enrolled onto a phase II evaluation of induction chemotherapy with cisplatin/fluorouracil for advanced head and neck carcinomas and had failed to achieve a partial remission after one treatment cycle. Palpable cervical tumors were heated to 40 degrees to 42 degrees C for 30 to 40 minutes, during which time cisplatin (100 mg/m2) was infused intravenously. A 5-day infusion of 5-fluorouracil (1000 mg/m2/d) followed. Despite less than a partial response to previous cisplatin/fluorouracil chemotherapy alone, two patients had complete clinical resolution of the heated tumor volume with two cycles of the combined thermochemotherapy approach. One patient achieved a partial remission with this approach. The remaining two patients died shortly after the initial thermochemotherapy treatment, as a result of progressive tumor growth. The two complete responders were subsequently treated with radiation (1 patient) and radical neck dissection (1 patient) and remained without evidence of disease 2 and 26 months after the completion of therapy, respectively. The toxicity of this combined modality approach was acceptable and appeared to be no greater than had been experienced during earlier treatment with chemotherapy alone. Further studies using a combination of these treatment modalities for locally advanced head and neck carcinomas are warranted.

Aged↗

PubMed1990

Comparison of photosensitizers in saline and liposomes for tumor photodynamic therapy and skin phototoxicity.

The uptake and distribution, skin phototoxicity, and direct tumor ablative potential of three porphyrin photosensitizers: hematoporphyrin derivative (HPD), dye hematoporphyrin ether (DHE), polyhematoporphyrin esters (PHE), and of Rhodamine-123 (Rh-123) have been studied in the AJ-CR inbred albino female mouse implanted with C-1300 neuroblastoma. Photosensitizer delivery was studied using saline and liposome carriers. The ratio of tumor uptake of the porphyrin compounds compared to the tumor-bed musculature and skin was favorable with both saline and liposome delivery. Rhodamine-123 precipitated in saline but was delivered effectively throughout the body in liposomes. There was no selective uptake by tumor cells of Rh-123 in this tumor model. Skin phototoxicity with the porphyrin compounds was mildly decreased using liposomes carriers while Rh-123 demonstrated no skin phototoxicity. DHE had the greatest tumoricidal effect among the porphyrin compounds. PHE has the potential of increased effect due to the ability to use higher light dosages in the activation of this porphyrin. Rhodamine-123 had no tumor effect in this animal model. Clinical implications of phototherapy with these four compounds are addressed.

Animals↗

PubMed1990

Selective management of early glottic cancer.

Seventy patients with stage I and II glottic cancer were treated at the University of Utah School of Medicine hospitals from 1980 through 1987. Forty-four patients had stage I cancer and 26 patients had stage II. The overall survival in the stage I group was 82%. Primary site control was 93% with only three deaths due to laryngeal cancer. Local control rates were 93% with CO2 laser excision, 80% with CO2 laser and irradiation, and 67% with radiation alone. Stage II glottic patients had an overall survival of 61.5% with a local control rate of 76%. Twenty-one of 24 patients were treated by full-course irradiation. Of the eight patients who recurred at the primary site, all were irradiation failures who had initial bulky disease and impaired vocal cord mobility. Selective CO2 laser excision was highly effective, whereas radiation therapy results were somewhat disappointing. Open partial laryngectomy should be considered in bulky stage II disease patients.

Adult↗

PubMed1990

Photodynamic therapy in otolaryngology-head and neck surgery.

Photodynamic therapy is an exciting area of current research. As discussed in this chapter, some successful clinical applications of this entity have been developed. Selective use of photodynamic therapy currently is of benefit to highly selected patients and holds the potential of help with some problems not currently well treated (like field cancerization). The potential utility of photodynamic therapy coupled with other cancer therapies is very intriguing. The whole area of photodynamic therapy in viral disease is just being opened to clinical investigation. As laser technology improves and as laboratory experience with known photosensitizers continues and new photosensitizers are developed, more significant clinical contributions will surely be made.

Head and Neck Neoplasms↗

PubMed1989

Prognostic indicators in head and neck cancer patients receiving combined therapy.

In 1983 we initiated a prospective nonrandomized study of the value of preoperative chemotherapy in previously untreated patients with stages III and IV squamous cell carcinoma of the head and neck. In 1983 and 1984, 50 patients were entered in the study. Prior to therapy all patients were evaluated by a representative from the Medical Oncology, Radiation Therapy, and Head and Neck Surgery Divisions, University of Utah School of Medicine, Salt Lake City. In addition to the standard preoperative evaluation, pretreatment computed tomographic scans were performed on all patients. Follow-up computed tomographic scans were performed after the second cycle of chemotherapy and at the completion of treatment. Initial therapy in all patients consisted of induction chemotherapy with cisplatin (day 1, 100 mg/m2) and fluorouracil (days 1 through 5, 1000 mg/m2). Several factors were examined for their utility in predicting response to therapy and survival. Factors evaluated included: (1) extent and timing of chemotherapeutic response; (2) computed tomographic quantitated primary tumor size; (3) size of computed tomographic quantitated regional (neck) metastases; (4) performance status; (5) cancer stage; (6) total lymphocyte count; and (7) serum liver function tests. The factor found to be most useful in predicting improved survival was the extent of response to chemotherapy. The remaining factors, performance status, regional lymph node status, serum gamma-glutamyltransferase levels, and cancer stage, were also found to correlate with length of survival but were much less important than the response to chemotherapy.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1988

Effects of photosensitizer (hematoporphyrin derivative-HPD) and light dose on vascular targets in the albino mouse ear.

Photodynamic damage to normal tissues, including skin, appears to occur by photooxidative damage to the normal microvasculature as the primary target sensitized by HPD bound to the vascular wall or endothelial cell. Initial damage to the microvasculature was measured by the increase in vascular permeability (VP) as measured by Evans Blue dye (EB) extravasation as a function of HPD and laser light (632 nm) dose. Albino, Swiss-Webster mice (female 122-25 g, 5 mice per group) were injected intraperitoneally (IP) with incremental doses of HPD (Photofrin II, Photofrin Medical, Inc.) (1, 10, 20, 30, 40 and 50 mg/kg). After 48 hours the left ear of each mouse was masked as a control and the right ear was irradiated at 632 nm using the Aurora-Lexel Argon-dye laser (Cooper Laser Sonics, Inc.) with an intensity of 50 mW/cm2 and light doses of 0, 25, 50, 75, and 100 J/cm2 directed to a 3-mm spot on the mouse ear. No EB leakage occurred in the absence of HPD at any light dose or in the absence of light at any HPC dose. Vascular permeability increased as a function of HPD dose up to 30 mg/kg. AT 50 mg/kg HPD, there was a decrease in VP. At each HPD dose above 10 mg/kg, the VP increased as a function of light dose up to 75 J/cm2. Further increase in light dose was without effect. The amount of HPD porphyrin recovered from irradiated ears decreased as a function of light dose. There appeared to be an irreversible photo destruction of the porphyrin exposed to light.

Capillary Permeability↗

PubMed1987

Computerized nuclear morphometry: a reproducible cytopathologic marker of head and neck cancer.

Computerized nuclear morphometry (CNM) has been compared with the standard histopathologic grading of squamous cell carcinoma in patients who have undergone chemotherapy for head and neck cancers. Statistics were significant between the histopathologic and CNM readings that were done. CNM represents an objective method of quantitating the histopathologic readings of nuclear pheomorphism and cancer differentiation to allow these criteria to be used as prognostic indicators in squamous cancers. CNM readings of individual biopsy specimens from patients were shown to characterize each tumor. This may represent a cytopathologic method for tracking a cancer through whatever course of therapy is given.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1987

Non-Hodgkin's lymphoma of the head and neck: CT evaluation of nodal and extranodal sites.

Forty-five patients with non-Hodgkin's lymphoma (NHL) of the extracranial head and neck who had undergone CT as part of their evaluation were reviewed to assess the impact of CT on clinical management. The sites of tumor deposition were subdivided by location: I, nodal; II, extranodal, lymphatic (Waldeyer's ring); and III, extranodal, extralymphatic (orbit, sinonasal, deep facial spaces, mandible, salivary gland, skin, and larynx). The CT appearance of NHL in each of the three locations was analyzed for characteristic CT signatures. Nodal NHL was suspected when CT showed multiple, large, homogeneous lymph nodes, often in unusual nodal chains of the head and neck. Extranodal, lymphatic NHL of Waldeyer's ring was indistinguishable from squamous cell carcinoma of this area unless synchronous tumor deposit in an extranodal, extralymphatic location was also present. When NHL was in nodes and/or Waldeyer's ring, CT-derived information was of limited clinical value since treatment was unfocused (chemotherapy and/or large-field radiotherapy). The CT appearances of extranodal, extralymphatic NHL was generally not distinguishable from other malignancies of these areas. However, CT-derived information regarding deep-tissue tumor size and extent was critical to planning the radiotherapy ports.

Adult↗

PubMed1987

Treatment of hypopharyngeal carcinoma: a 10-year review of 1,362 cases.

A computer search of cancer patients enrolled in the Rocky Mountain Cancer Data System between 1973 to 1983 revealed 1,362 patients with hypopharyngeal cancer, 1,208 of whom could be staged by the American Joint Committee on cancer staging criteria. Stage I and II patients comprised 17.5% while 71% were either stages III or IV. The distant metastatic rate in advanced stage patients was 24%. Survivals for all treated patients were 65% at 1 year, 33.5% at 3 years, and 25% at 5 years. Three-year survivals were 54.5% for the surgery only group, 41.6% for the combined therapy group, and 17.7% for the irradiation only group. Five-year survivals for the surgery only group were 39.8%, combined therapy, 31.8%, and irradiation only 11.5%. These figures are actuarially corrected. Twenty-two percent of combined therapy patients had preoperative irradiation versus 78% who had postoperative irradiation. There was no statistically significant difference seen between these two groups.

Carcinoma↗

PubMed1986

Otosurgical model in the guinea pig (Cavia porcellus).

The guinea pig is a useful model for otologic research. Common problems encountered in working with individual animals include preexisting chronic middle ear disease, anesthetic deaths, and a lack of knowledge of the surgical anatomy and landmarks of the middle and inner ear. The methods detailed in this article will benefit those interested in a reliable, inexpensive, otosurgical animal model.

Anesthesia↗

PubMed1986

The tailored CT evaluation of persistent facial nerve paralysis.

The clinical, radiographic, and pathologic records of 39 patients with peripheral facial nerve dysfunction seen from October 1981 through July 1984 are reviewed. The extent of preradiologic clinical localization of suspected lesions and their subsequent pathologic confirmation is correlated to the number, sequence, and type of radiographic evaluations performed.

Adolescent↗

PubMed1986

Laser photocoagulation of vascular malformations of the tongue.

Vascular malformations of the tongue (hemangiomas, lymphangiomas, AV fistulae, etc.) compromise a significant portion of head and neck angiodysplastic lesions. Complications requiring treatment include bleeding, pain, and difficulties related to increased tongue volume. Treatment modalities have included embolization, excision, cryotherapy, sclerosis, radiation, and chemotherapy. The more aggressive therapies often result in major functional disability to loss of lingual tissue. A series of nine patients has been treated for one or more of the complications of lingual vascular malformations with either argon of Nd:YAG laser photocoagulation. The therapeutic objective was provision of symptomatic relief with conservation of functioning lingual tissue. Results have varied from good to excellent with markedly decreased bleeding frequency as well as reduction in lesion size. No serious complications, such as bleeding or invasive infection, have been noted. Laser phototherapy is beneficial in the palliation of selected benign lingual vascular malformations.

Adolescent↗

PubMed1985

Computed tomography of cervical lymph nodes. Staging and management of head and neck cancer.

Forty patients with head and neck cancer had a computed tomographic (CT) scan followed by lymphadenectomy and pathologic confirmation. The overall accuracy of clinical examination of the neck was 70% vs 93% by CT. The CT correctly "upstaged" the neck in nine patients. One was upstaged from NO to N1, and four each from NO to N2 and N1 to N2. It correctly "downstaged" the neck in one patient (from N2 to N1). Eight patients had extranodal disease on CT confirmed by pathology. The CT findings were correct in ten of 11 previously treated patients. Because CT is more accurate than the clinical examination, it should be included in the staging of not only the primary tumor but also nodal disease of the neck. It can have an important role in the management of head and neck cancer.

Adult↗

PubMed1985

Multimodality therapy for unresectable squamous cell carcinoma of the head and neck.

Eighteen patients with unresectable Stage III or IV squamous cell carcinoma of the head and neck were treated with induction therapy consisting of sequential methotrexate and 5-fluorouracil. This was followed by full course radiation therapy and radical neck dissection for those with residual neck disease. Those with local control were then treated with vinblastine, bleomycin, and cisplatin (VBP). Although 79% of patients achieved a partial or complete response to chemotherapy, only 50% of patients achieved local control. Marked mucositis limited the dose and schedule of radiation therapy. The methotrexate and 5-fluorouracil combination appears to be too toxic for multimodality therapy of advanced head and neck cancer.

Adult↗

PubMed1985

Infection and tumor of the masticator space: CT evaluation.

The masticator space is a distinct deep facial space, bounded by the superficial layer of deep cervical fascia and containing the four muscles of mastication and the ramus and posterior body of the mandible. Trismus often complicates evaluation of masticator space disease. However, computed tomography (CT) clearly delineates the normal and pathologic anatomy of this region. The CT appearance of the masticator space was demonstrated in a retrospective review of 32 patients with either infection or tumor involving this space. Masticator space infections were found to have characteristic CT appearances and patterns of spread. CT was especially useful in differentiating inflammation from frank abscess, detecting mandibular osteomyelitis, and directing surgical drainage to the precise deep-tissue space involved. In cases of tumor, the primary utility of CT was in defining tumor extent accurately and in helping to assess resectability and determine radiation therapy ports.

Abscess↗

PubMed1985

The pectoralis myocutaneous flap for salvage of necrotic wounds.

The authors have utilized six pectoralis major myocutaneous flaps in attempts to salvage extensive necrotic wounds of the pharynx and neck. The flap was employed in the following situations: massive necrosis of the entire neck skin with both carotid artery systems exposed, radiation necrosis of the neck skin with exposure of carotid artery, dehiscence of gastric pull-up from pharynx with resultant carotid exposure, failed trapezius flap in a radionecrotic oral cavity, and two cases of pharyngocutaneous fistula with extensive soft tissue necrosis. These flaps achieved healing in all cases. One death occurred 3 weeks following complete cutaneous healing secondary to a ruptured carotid pseudoaneurysm. One flap underwent total skin loss but the entirety of the muscle survived and the fistula was successfully closed with the back of the muscle being subsequently skin grafted. One case of dehiscence of the flap from oral mucosa resulted in a minor exposure of mandible with limited osteoradionecrosis controlled by topical means. This flap has performed extremely well in these precarious and difficult situations that previously may not have been salvageable. It has also been effective in abbreviating the required hospitalization and wound care. We conclude that the pectoralis myocutaneous flap should be the primary choice for the management of extensive postsurgical wound necrosis.

Aged↗