Intraoperative electron beam radiation therapy (IOEBRT) for carcinoma of the exocrine pancreas.

The abdominal cavities of 50 patients were explored in a specially constructed intraoperative radiotherapy operating amphitheater at the Medical College of Ohio. Twenty-six patients were treated with intraoperative and postoperative precision high dose external beam therapy, 12 with intraoperative irradiation but no external beam therapy, and 12 with palliative surgery alone. All but two patients completed the postoperative external beam radiation therapy as initially prescribed. The median survival time for patients treated with palliative surgery alone was 4 months, and that for patients treated with intraoperative radiotherapy without external beam therapy was 3.5 months. Patients undergoing intraoperative irradiation and external beam radiation therapy had a median survival time of 10.5 months. Four patients died within 30 days of surgery and two patients died of gastrointestinal hemorrhage 5 months posttreatment.

Radiotherapy in the treatment of pancreatic cancer.

In the last two decades, we have witnessed revolutionary advances in pancreatic imaging as well as increased availability of megavoltage radiotherapy equipment and sophisticated radiotherapy planning devices. Several advances in the radiotherapy of pancreatic cancer have been made for the patient with resectable disease. Postoperative radiotherapy combined with chemotherapy confers a survival advantage after 'curative' resection. Preoperative and intraoperative intraoperative radiotherapy may do the same, but this requires further evaluation. Preoperative irradiation may improve the resectability rate, but the clinical data are still very limited. For locally unresectable disease, PHD radiotherapy with adjuvant 5-FU should now be the standard treatment in suitable cases with a median survival time of about one year. High LET radiation beams have failed to produce improved survival in two prospective randomized studies. Intraoperative radiotherapy is an effective means of pain control and enhances control of local disease, but has not been shown to improve survival rate significantly. Interstitial radiotherapy also improves local control, but it is associated with a high mortality rate and an even higher major complication rate. Wide-area radiation therapy and preoperative radiotherapy both seem to show promise in this group of patients. Patients with metastatic disease should be treated palliatively on an individual basis.

A pilot study investigating intraoperative electron beam irradiation in the treatment of ovarian malignancies.

Intraoperative electron beam radiation therapy (IOEBRT) in the treatment of ovarian malignancies was investigated at the Clement O. Miniger Radiation Oncology Center (COMROC). Nine patients were operated in the COMROC IOEBRT operating amphitheater and five were found to have disease sufficiently limited to allow for IOEBRT. The patients' ages ranged from 13 to 80 (median 53) years. Five patients had serous cystadenocarcinoma, one papillary adenocarcinoma, one mixed germ cell tumor, one squamous cell carcinoma, and one granular cell tumor of the ovary. The median survival of the non-IOEBRT group was 13 (range 12-29) months, while the IOEBRT group's median survival was 14 (range 18-46) months. All of the patients tolerated IOEBRT well without addition to the surgical morbidity.

A study of effective attenuation coefficient for calculating tissue compensator thickness.

Dose uniformity throughout the treatment volume is essential to precision radiation therapy. Tissue compensators are often used as a means to eliminate dose nonuniformity resulting from surface contour irregularities. This paper evaluates the accuracy of using an effective attenuation coefficient for calculating the thickness of missing tissue. This coefficient is found to vary strongly with thickness of missing tissue when the initial depth is situated in the buildup region. The use of a single attenuation coefficient produces errors as high as 54% in the calculated compensator thickness when 10-MV x rays are used. At depths greater than the depth of maximum dose, the attenuation coefficient remains a function of field size, not the initial depth.

Treatment of cancer of the pancreas by intraoperative electron beam therapy: physical and biological aspects.

Radiation therapy has had a significant and an expanded role in the management of cancer of the pancreas during the last decade. In particular, for locally advanced disease, radiation therapy has improved the median survival of patients to 1 year. Intraoperative electron beam therapy has been applied to unresectable and resectable pancreatic cancer in an attempt to enhance local control of disease and to improve patient survival. This paper presents a survey of the role of radiation therapy in treatment of cancer of the pancreas, provides information on the radiobiological aspects of this treatment modality and details the physical and dosimetric characteristics of intraoperative radiation therapy with electrons. Presented are the design specifics of an applicator system, central axis beam data, applicator parameters, dose distribution data, shielding, treatment planning and means of verification. Emphasis is placed on the collaboration and cooperation necessary for all members of the intraoperative radiation therapy team including surgeons, radiation therapists, medical physicists, anesthesiologists, technologists, and nurses.

Prostaglandin synthetase and prostaglandin E2 levels in human breast carcinoma.

Prostaglandin synthetase activity and tissue prostaglandin E2 levels were measured in 53 human breast carcinoma specimens. Each set of data is log-normally distributed. There is a weak but statistically significant correlation between prostaglandin synthetase activity and tissue prostaglandin E2 levels of individual specimens. In addition, in a series of four rat mammary tumors, a rough correlation between prostaglandin synthetase activity and tissue prostaglandin E2 levels was observed. The data suggest a multifactorial explanation for abnormalities of prostaglandin metabolism in human breast cancer.

Estrogen receptor levels in multiple biopsies from patients with breast cancer.

The results of estrogen receptor assays of more than one sample of breast carcinoma in sixty-two patients are reviewed. There was an overall disagreement of 28 per cent between two simultaneous samples, and in the asynchronous group there was a statistically significant difference (p is less than 0.05) in the interval between those who remained positive and those who became negative. As a practical policy, decisions regarding endocrine ablation should be made on contemporary estrogen receptor status rather than on the status of the primary lesion.

Chromatographic patterns of prostaglandins using different lots of silicic acid.

The chromatographic patterns of prostaglandin E2 chromatographed on various lots of silicic acid are presented. Two lots of Mallinckrodt silicic acid tested give totally unsatisfactory separation of PGE2. Sigma silicic acid SIL-R gives better separation than any of the Mallinckrodt lots tested. Increasing the size of the "E" fraction of solvent can give satisfactory separation on Mallinckrodt silicic acid.

Estrogen receptor levels in hormonally progressive mammary tumors.

Tumor samples from 4 different stages of hormonal progression in the MT-W9 series of rat mammary tumors were analyzed for estrogen receptors by the dextran-coated charcoal method in order to further explore the clinical implications of the estrogen receptor assay. The findings indicate that although the presence of estrogen receptors is not an exclusive characteristic of hormonal dependency, their absence is indicative of a later stage of hormonal progression which might be of more immediate clinical consequence because hormonally autonomous tumors have faster growth rates than hormonally dependent tumors. It is also suggested that it may be necessary to initiate chemotherapy as an adjuvant to endocrine therapy for metastatic breast cancer patients with hormonally dependent tumors in order to avoid the eventual proliferation of hormonally autonomous tumor cells which are present in hormonally dependent tumors.