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Biomedical subjects

H D Suit

Publications and source records attributed to H D Suit.

At least 19 recordsLinked to original sources
PubMed1979

Proton radiation as boost therapy for localized prostatic carcinoma.

A 160-MeV proton beam has been modified to irradiate patients with localized tumors by using convention treatment schedules. This proton beam has the physical advantage of megavoltage x-rays of reducing the radiation dose to normal tissues adjacent to the tumor volume. A perineal proton technique used as boost therapy (2,000 to 2,500 rads) was evaluated in the definitive irradiation of 17 patients with localized prostatic carcinoma. This technique allows repeated daily treatment of the carefully defined target volume with a precision of +/- 2 mm. Total dose to the prostatic tumor, but not to the posterior rectum, has been increased by 500 to 700 rads. After 12 to 27 months of observation, no noteworthy rectal reaction has developed in a patient, easily managed urethral strictures have developed in two patients, and all but one are locally controlled.

Adenocarcinoma↗
PubMed1979

Proton irradiation of malignant melanoma of the ciliary body.

This is our first case of malignant melanoma of the ciliary body treated with proton beam irradiation, a technique that we developed for irradiating choroidal melanomas. After 21 months of follow-up no growth of the tumour has been observed, and shrinkage of the tumour was noted on the follow-up photographs and by ultrasonography. The 32P uptake test, which was positive before treatment, turned negative 14 months after irradiation. The described technique of proton beam irradiation might offer an alternative for the treatment of ciliary body melanomas when the present techniques of iridocyclectomy cannot be applied because of the size of the lesion.

Ciliary Body↗
PubMed1979

Time-temperature relationship th hyperthermic treatment of malignant and normal tissue in vivo.

The effect of hyperthermia on normal and tumor tissue was studied following water bath heating of a methylcholanthrene-induced fibrosarcoma (FSaI) isotransplanted into the feet of C3H mice. The time-temperature relation for the 50% tumor control dose over the temperature range of 41.5--45.5 degrees showed a log linear relationship which followed a biphasically modified Arrhenius plot. At temperatures above 43 degrees, there was a 50% reduction in heating time to obtain the 50% tumor control dose for each 1 degree increase in temperature, corresponding to an activation energy of 140 kcal/mol. At temperatures below 43 degrees, the curve was steeper, with a tendency to double the treatment time for each 0.5 degree reduction in temperature (activation energy, approximately 230kcal/mol). Normal tissue damage in the tumor-bearing foot was estimated at two levels with a 50% response dose assay. Severe normal tissue damage showed a time-temperature relationship similar to the tumor response, thus indicating no variation in therapeutic ratio at different temperatures. However, for slight tissue damage, the therapeutic ratio increased with decreasing temperatures, yielding a better therapeutic ratio at lower temperatures. The time-temperature relationship obtained in the FSaI fibrosarcoma is supported by other studies and points to a general time-temperature relationship for hyperthermic tumor destruction.

Animals↗
PubMed1979

Enhancement of the thermal response of animal tumors by Corynebacterium parvum.

The effect of Corynecbacterium parvum treatment on the thermal response of animal tumors was studied. Tumors were methylcholanthrene-induced (FSa-II) and spontaneous (FSa-I) fibrosarcomas in C3Hf/Sed mice. C. parvum was given i.v. and was followed by local hyperthermia at 43.5 degrees 3 days later. Cell survival determined by lung colony assays showed that preadministration of C. parvum insignificantly enhanced the thermal response of both tumors. Studies of delay of tumor growth for FSa-II demonstrated that the enhancement ratio decreased with increasing time of treatment and reached a minimum of approximately equal to 1.7. The enhancement ratio for the time at hyperthermia which achieved tumor control in one-half of the treated tumors was 1.7. Together with our previous results on normal tissue responses, the therapeutic gain factor for obtaining 50% tumor control was found to be 1.1 (1.7/1.55) for the weekly immunogenic FSa-II tumor, while it was 2.3 for moderately immunogenic FSa-I as reported previously.

Animals↗
PubMed1978

Proton irradiation of choroidal melanomas. Preliminary results.

Choroidal malignant melanomas in nine patients were treated with proton beam irradiation at the Harvard Cyclotron Laboratory, Cambridge, Mass. Each patient received five proton beam treatments in eight to ten days, totalling 4,730 to 8,570 rads at the tumor. No complications occurred during the treatment or follow-up period, which, at the time of this writing, ranges from one to 24 months, with an average of 12 months. No further growth of the tumor has been observed in any patient. Different signs of tumor regression have been noted. Resolution of the serous retinal detachments that accompanied some tumors is the earliest finding. Pigment changes over the surface of the tumor and adjacent pigment epithelium is a usual initial tumor response. Fluorescein angiography initially showed decreased leakage of dye; later, destruction of the tumor's vasculature and elimination of fluorescein leakage became evident. Only large choroidal vessels remained patient. Ultrasonography revealed decreased height of the tumors postirradiation, and the radioactive phosphorus (32P) uptake test, repeated in one patient, turned negative on postirradiation measurements.

Aged↗
PubMed1978

A preliminary study of intralesional, intralymph node, intravenous and intraperitoneal Corynebacterium parvum treatments in patients with advanced cancer.

Twenty-one patients with squamous cell carcinoma of oral cavity and/or cervical lymph node and four patients with soft tissue sarcomas were given intralesional (2-4 mg/m2) and intralymph node (2-4 mg/m2) C. parvum injections followed by 5 intravenous (2-4 mg/m2) C. parvum treatments and conventional therapies. Seven patients with Stage III ovarian carcinomas were given intraperitoneal (2-4 mg/m2) C. parvum injections followed by conventional therapies. The local and systemic effects of the C. parvum treatments were described and the anti-tumor effects were evaluated in this series of patients.

Adult↗
PubMed1977

Soft part tumors.

Results of management of rhabdomyosarcoma of childhood have improved in a dramatic manner during the recent 10 years as a consequence of the treatment by three modality approach which relies on an intensive multi-drug multicycle chemotherapy regimen combined with radiation therapy and or surgery. Both local results and total disease-free survival rates are markedly better with this more comprehensive approach. A staging system for sarcoma of soft tissue has just been developed by the A.J.C. Histopathological grade is the important parameter: stage 1,2, and 3 are tumors of histological grades 1, 2, and 3 respectively (an outline of the system is presented). Treatment results of 100 patients with sarcoma of soft tissue (extremities 89, torso 11) treated by radical dose radiation therapy (less than 6300 rad) and limited surgery at M.D. Anderson Hospital are presented. For both local control and disease free survival, results decreased with advancing stage and anatomic site was not a factor per se. Radiation therapy under tourniquet induced hypoxia was not found to be significantly more effective than conventional radical dose therapy. The necessity of planning treatment such that if subsequent surgery is required, the fields will provide the best distribution of unirradiated or low dose tissue for preparation of flaps, etc.

Adult↗
PubMed1977

A clinical and pathological staging system for soft tissue sarcomas.

A system for staging the clinical status of patients with soft tissue sarcomas is presented, based on the clinical characteristics of the primary tumor (size, extension), the involvement of lymph nodes, the presence of metastases, and the grade of the tumor. This represents the TNM system with grade of tumor (G) added. The system evolved was based on examination of 1215 cases of 13 types of soft tissues sarcomas, primarily in the extremities (fibrosarcoma, liposarcoma, etc.). Nine stages are described, and they are correlated with survival in the cases reviewed. The staging system now can be used for case evaluation for therapy determination and for intercomparison of series of patients as to incidence of different kinds of tumors, effects of treatment, and survival.

Adult↗
PubMed1977

Proton irradiation of small choroidal malignant melanomas.

Five patients with choroidal malignant melanomas were treated with proton irradiation with a cyclotron. We developed an accurate method of aiming the proton beam within the eye. Four to five tantalum rings, 2 mm in diameter, were sutured to the sclera at the edges of the tumor, which is localized by indirect ophthalmoscopy and transillumination. The rings were used as markers for stereotactic radiography to align precisely the tumors with the proton beam. The patients were given a total tumor dose of 4,730 to 6,670 rads, delivered in five equal fractions, over a period of eight to nine days. All patients tolerated the treatments well without any adverse effects. The tumor response to therapy could not be evaluated at the completion of treatment since there was no immediate observable reaction of the tumor or of the surrounding retina. Although there has been no definite regression in any patient, we observed a change in the "color" of the tumor in the first two patients and resolution of two serous retinal detachments.

Choroid Neoplasms↗
PubMed1977

Hyperthermic effects on animal tissues.

TCD50 values for thermally resistant tumors have been significantly reduced. The therapeutic ratio has been improved for some tumor-normal tissue situations and treatment protocols, but not for others. The oxygen enhancement ratio (OER) for hyperthermic damage may be congruent to 1; if this is true for tumor cells in vivo, the combination of hyperthermia and radiation should improve the therapeutic ratio to the extent that hypoxic cells are critical. There does not appear to be a differential response to hyperthermia by the normal foot or tumor growing in the foot pad for the following two parameters: (a) relationship between heating time to produce the specified response and the level of heating, and (b) effect of fractionation of hyperthermia.

Animals↗