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Biomedical subjects

C T Chung

Publications and source records attributed to C T Chung.

49 records · Page 3Linked to original sources
PubMed1980

External irradiation for malignant thyroid tumors.

Thirty-eight patients with residual or recurrent primary thyroid cancers which did not take up 1-131 were treated with external beam irradiation. Excluding 5 patients with malignant lymphoma, there were 23 patients with local disease and 10 with distant metastases. Doses ranged from 3,500 to 7,000 rads (35-70 Gy) among the 23 with local disease; local tumor control was achieved in 8. Six are alive and well 2-11 years later. External beam irradiation should be considered in locally advanced, incompletely resected, recurrent and metastatic thyroid malignancies of all histological types without 1-131 uptake. Reviewed are the age and sex distribution, histology, stage, extent of surgery, and dose and radiotherapy technique as they affect survival and patterns of failure.

Adenocarcinoma↗
PubMed1980

Identification, purification, and partial characterization of an organic anion binding protein from rat liver cell plasma membrane.

Uptake of bilirubin, sulfobromophthalein (BSP), and other organic anions by the liver is a process with kinetics consistent with carrier mediation. The molecular basis of this transport mechanism is unknown. In the search for the putative organic anion carrier or receptor, the interaction of BSP with rat liver cell plasma membrane (LPM) has been studied. Specific binding of [(35)S]BSP to LPM was determined using a filtration assay. Results revealed high affinity (K(a) = 0.27 muM(-1)), saturable (6.3 nmol/mg protein) binding, which was eliminated after preincubation with trypsin. Although [(35)S]BSP was strongly bound to LPM, the binding was rapidly reversible, preventing direct identification and study of a specific binding site(s). To avoid this problem, a photoaffinity probe was devised, in which [(35)S]BSP is covalently bound to LPM after exposure to ultraviolet light. Subsequent sodium dodecyl sulfate gel electrophoresis and fluorography revealed radioactivity predominantly associated with a single 55,000-mol wt protein. A protein with identical electrophoretic mobility was purified from deoxycholate solubilized LPM after affinity chromatography on glutathione-BSP-agarose gel. This protein migrated as a single band on sodium dodecyl sulfate gel electrophoresis and on urea gel isoelectric focusing. It contained 1-2 residues of sialic acid per 55,000-dalton protein, and was immunologically distinct from rat albumin and ligandin. It bound bilirubin with a K(d) of 20 muM, as determined by tryptophan fluorescence quenching. Although the high affinity of this LPM protein for organic anions suggests that it may function as a hepatocellular organic anion receptor, its role in transport of these compounds is unknown.

Animals↗
PubMed1979

Irradiation of primary brain-stem tumors.

Of 40 patients treated for brain-stem tumors, 20 had lesions of the thalamus and midbrain (group A) and 20 had lesions of the pons and medulla (group B). Performance status measured 1 month after irradiation improved in 16 of 20 group A and 11 of 20 group B patients and was a valuable prognostic factor. The survival rate at 5 years was 40% (8/20) in group A and 30% (6/20) in group B. All recurrences appeared within 3 years and were predominantly locoregional. Treatment factors, including dose and field size, are analyzed.

Adolescent↗
PubMed1979

High dose preoperative irradiation of the lower neck and supraclavicular fossae.

Preoperative irradiation of 5,000 rad in 5 weeks before total laryngectomy with radical neck dissection was compared for two groups of patients: (1) those treated to a smaller volume through lateral opposed fields (37 patients) and (2) those treated to a larger volume by adding a third field directed to the lower neck and supraclavicular fossae (46 patients). There were no significant differences in tolerance to irradiation or in postoperative complications. However, locoregional tumor control improved significantly from 63% to 90% (P less than 0.02) with the three-field technique, and all four stomal recurrences were in the two-field group. Deaths from intercurrent disease and from distant metastases without local recurrence account for the failure to improve the overall survival rate.

Adult↗
PubMed1978

Voice change after radiotherapy. Some preliminary results.

A one-third octave spectral analysis was performed on two sentences spoken by 5 patients with laryngeal cancer, 5 with head/neck cancer not involving the vocal cords, and 12 normal subjects. Recordings were made prior to and at weekly intervals during radiotherapy as well as at periodic intervals post-treatment. Patients with laryngeal cancer exhibited lower spectral levels than normal throughout radiotherapy as well as several months post-treatment. By one year after treatment, the spectral levels of these patients were largely in the normal range. Patients with head/neck cancer not involving the vocal cords exhibited greater than normal sound pressure levels throughout most of the spectrum. These levels remained high even at one month post-treatment. Irradiation of normal vocal cord tissue also seems to result in higher spectral levels.

Aged↗
PubMed1978

Complications of high dose preoperative irradiation for advanced laryngeal-hypopharyngeal cancer.

The authors studied 162 patients with advanced cancer of the laryngopharynx who were treated over the same period of time by standard techniques. High dose preoperative supervoltage irradiation to 5000 rads/5 weeks through large opposed lateral fields and a lower anterior neck field is not accompanied by a prohibitive increase in mortality or morbidity for patients with stage III-IV largynogopharyngeal cancer. Rescue surgery for recurrence after definitive irradiation can be accomplished.

Adult↗
PubMed1977

Use of computerized axial tomography of the head and neck region.

The use of the computerized axial tomography has been well received in the field of otolaryngology. Five cases are presented illustrating the capability of the total body scanner (Delta scanner) to contribute to radiologic diagnosis below the level of the base of the skull. The advantages of non-invasibility and three dimensionality are compared to the disadvantages of added cost, added radiation exposure, comparatively long exposure time and relatively poor detail. Because of the overall usefulness of this diagnostic tool, evolution of rapid scanning devices with greater detail is awaited with interest.

Adult↗
PubMedDate not supplied

High dose preoperative irradiation for advanced laryngeal-hypopharyngeal cancer.

Combined therapy, consisting of 5000 rads delivered in five weeks by total laryngectomy +/- radical neck dissection, was compared with treatment by irradiation (6000-7000 rads) with surgical salvage when clinically possible for radiation failure. Patients were categorized according to site of primary cancer (glottic, supraglottic and pyriform sinus) and staged (T, N, M). Survival was equally good in the two programs for glottic and supraglottic lesions, N0 or N1. The combined treatment program was judged superior for supraglottic and pyriform sinus lesions, N2 or N3.

Adult↗
PubMedDate not supplied

Carcinoma of the anterior tongue.

We have reviewed 126 patients with squamous cell carcinoma of the anterior tongue. Our experience suggests that carcinoma of the anterior tongue is a highly aggressive disease. It is no less aggressive and dangerous than carcinoma of the posterior tongue. The clinically negative neck is a problem. Many clinical stage I and II cancers are, in fact, stage III when analyzed by the pathologist. This difficulty in clinical staging results in a significant management problem when stage III carcinomas are treated as stage I and stage II disease. Management, if it is to cure, must be aggressive. An adequate, wide surgical resection will control early carcinoma of the anterior tongue. Advanced cancers of the anterior tongue, clinical stages III and IV, should be widely excised; the cervical lymph nodes on the side of the primary lesion must be treated by surgery and radiation therapy. Treatment of the opposite side of the neck is indicated based on a high rate of metastases to contralateral lymph nodes in this series. Those patients treated with irradiation who had recurrence did so predominantly at the primary site of disease. Patients treated surgically tended to have recurrence in the regional cervical lymphatics.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Interruption of combined therapy: a factor in decreased survival.

Occasionally, during the course of combined (radiation plus surgery) treatment of head and neck malignancies, the patient experiences a profound response to radiotherapy alone and elects to decline the second phase of treatment, namely, surgery. After a variable interval, radiotherapy is reinstituted to a "curative" level. A series of 14 laryngeal and oropharyngeal carcinomas, treated in this disjointed fashion, has been examined with respect to long-term survival. The prognosis is extremely unfavorable, thus supporting a basic philosophy of continuing with the prescribed surgical treatment despite a dramatic response to noncancericidal doses of radiotherapy. The site and stage of tumor, radiation dosage, interval to completion of therapy, and incidence of local and distant metastases are examined. It appears that every effort should be made to provide continuity in the combined therapeutic protocol if the advantages of this mode of therapy are to be effective.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Management of craniopharyngioma.

PURPOSE: The management of craniopharyngioma does not have a consensus. Extensive surgery may be associated with major complications. The purpose of this study was to evaluate local tumor control and survival after limited surgery and postoperative radiotherapy. METHODS AND MATERIALS: Thirty patients with craniopharyngioma were treated at SUNY Upstate Medical University in Syracuse, NY from 1967 to 2000. The group consisted of 13 males and 17 females, and the median age was 35 years. The median follow-up was 71 months. Only two patients underwent complete tumor resection. Eighteen patients underwent subtotal resection, and 10 underwent decompressive surgery (ventriculoperitoneal shunt or cyst aspiration). Most (20/ 28) patients who had less than total resection received immediate postoperative radiotherapy. Four patients received conventional radiotherapy for recurrence. Gamma knife radiosurgery was used as part of the primary treatment in two patients and at the time of local tumor recurrence in three patients. RESULTS: The local control rate, including after salvage treatment, was 91% and 83% at 5 and 10 years, respectively. Salvage was radiotherapy, gamma knife or surgery. Ultimate local tumor control appeared better for patients who underwent subtotal resection (100% and 89% at 5 and 10 years, respectively) than for those who did not undergo resection (61% and 61% at 5 and 10 years, respectively). The overall survival was 93% and 83% at 5 and 10 years, respectively. Two patients underwent gross total resection, and one patient experienced recurrence 6 years after the surgery and was treated by gamma knife radiosurgery. Both patients are well without recurrence at 3 and 7 years after the initial surgery. Survival also appeared to be improved for the group who underwent subtotal resection (100% and 90% at 5 and 10 years, respectively) versus those who did not undergo surgery (73% and 73% at 5 and 10 years, respectively). The dose of radiotherapy > or = 50 Gy had no impact on local control or survival. Ten patients experienced surgery-related complications, and five had radiotherapy-related complications, including visual, cranial nerve, motor, and endocrine deficits. CONCLUSION: The extent of surgery appears to be an important prognostic factor for predicting outcome, although this may represent selection bias. Long-term disease control is excellent after subtotal resection and postoperative radiotherapy. Encouraging initial results have been seen with gamma knife radiosurgery, and the potential for gamma knife radiosurgery to replace more extensive surgical resection should be further explored.

Adolescent↗