Juan V. Fayos

Stereotaxic radiotherapy technique for small intracranial lesions.

A stereotaxic radiotherapy technique that permits accurate delivery of highly localized dose to a small intracranial target has been developed. The technique facilitates precise integration of the diagnostic and therapeutic procedures including target localization, treatment planning, simulation, repetitive patient irradiation, and daily treatment verification. A conventional linear accelerator and computed tomography scanner as well as special diagnostic and therapeutic guides are used. A suitable dosimetric distribution is achieved using arc therapy with small radiation fields and 10-MV x rays.

Radiation therapy of carcinoma of the tonsillar region.

From 1960 through 1976, 353 consecutive patients with carcinoma of the tonsillar region were primarily treated with radiation therapy. The mean age of patients was 58 years with males predominating (78%). Patients were classified according to a TNM and stage classification. Most of the tumors were large, and the specific site of origin could not be determined in 33% of the patients. The predominant identifiable sites were the soft palate and uvula, 18%, the anterior tonsillar pillar, 18%, and the tonsillar fossa, 13%. Patients were treated with radiation to doses of 6700 rad given in 48 days and 33 fractions using Cobalt 60 radiation. We found a 91.7% control rate for patients with T1 disease and 76.9%, 49.5%, and 25% for T2, T3, and T4 patients, respectively. The overall local control rate was 62.3%. Surgery was used most often in recurrences for Stage III patients. Salvage surgery was carried out in 93 patients. Surgery was more successful in controlling the disease in patients in whom the primary was controlled by irradiation. Overall, the tumors in 43% of the patients who had surgery were subsequently controlled as a result of this treatment. Metastasis occurred rapidly, with 75 of the patients exhibiting metastases by 18 months. Complications were not related to dose but were slightly higher in patients who had surgery (5%). We conclude that radiation therapy is the preferred treatment for Stage I and II squamous cell carcinoma of the tonsillar region. No satisfactory results were obtained in Stage IV; other approaches should be tried.

Dosimetry of small radiation fields for 10-MV x rays

Dosimetry for 10-MV x rays has been extended to radiation fields smaller than 4 X 4 cm which may be suitable for radiation therapy of small lesions, e.g., intracranial tumors, benign or malignant. Special consideration in this study was given to (i) the variation of dose with field size (collimator and phantom scatter), (ii) the central axis percentage depth doses, and (iii) the moving-beam therapy dose distribution. We conclude that simple dosimetric techniques can provide adequate physics background for stereotaxic radiosurgery with small radiation fields and high-energy x rays.

The role of radium implants in cancer of the oral cavity and oral pharynx

Abstract Eighty-five patients with squamous cell carcinoma of the oral cavity tonsillar region or base of the tongue received a radium implant. Implants were done as a supplement to external irradiation except in three patients in whom it was the sole form of treatment. The median dose was 8500 rad given in about 8 weeks, 6000–6500 rad given by opposing lateral fields using 60 Co radiation; 25% of the patients received doses higher than 8600 rad. The implant boosted the dose to the primary. Most of the patients who had radium implants had advanced disease. The overall control rate of the primary was 45.9%, the highest control achieved with smaller lesions. Surgery was performed in 26 patients for recurrence at the primary; five developed osteonecrosis of the jaw bone. The survival at 4 and 5 years was approximately equal for Stages I and II (80%); it was 40% for Stages III and IV.

Head and Neck Cancer: Reliability of American Joint Committee's staging system as prognostic indicator

The present American Joint Committee (AJC) staging system for the head and neck cancer does not satisfy the criteria as a prognostic or therapeutic indicator when patients are treated initially with radiation therapy. There are certain groups of patients allocated to advanced AJC stages where the prognosis is more favorable and, thus, should not be grouped with the poor prognosis stages. Recognition of these groups is important for any treatment planning or reporting of the end results.

Epithelial carcinoma of the ovary

Abstract A total of 176 patients with untreated epithelial cancer of the ovary received postoperative irradiation at the Alice Crocker Lloyd Radiation Therapy Center of the University of Michigan from 1955 to 1973. Irradiation was delivered to the pelvis alone or to the pelvis and part of the abdomen, depending on the extent of the disease and the location of the residual tumor. No patient received whole abdominal irradiation. Post-irradiation chemotherapy was administered to patients with advanced disease. Twenty-six patients with Stage III disease were treated according to a protocol consisting of pre- and post-irradiation administration of chlorambucil. The overall 5-year actuarial survival rate was 42%. The 5-year survival rates for patients with Stage I through IV disease were 77%, 31%, 23%, and 0% respectively. Patients whose tumor was grossly removed at the initial surgery did better (63 % 5-year survival rate) than patients whose tumor was only partially removed (26% 5-year survival rate). The pathologic grade of the tumor was a major factor determining the prognosis. The 5-year survival rates were 76 % for patients with well-differentiated carcinomas, 33% for those with moderately differentiated carcinomas, and 14% for those with poorly differentiated carcinomas. Thirty-four (20%) of the patients were found to have at least a second primary tumor either at the time of the initial surgery or some other time. Autopsy results for 25 patients in this series are presented.

Computer Controlled Hyperthermia Unit for Cancer Therapy

A versatile hyperthermia control system, based on a microcomputer, provides automated temperature regulation (1 channel) and monitoring (3 channels) and control of microwave output (both on/off and power level), and displays temperature (degree C) and microwave output (watts) graphically in real time; all data are stored on floppy diskette.