Radiation and chemotherapy. Treatment of localized pancreatic carcinoma.

Patients unable to undergo a pancreatoduodenectomy for adenocarcinoma of the pancreas are often treated with radiation therapy. A randomized trial by the Gastrointestinal Tumor Study Group has shown an advantage in combining it with chemotherapy. A similar size retrospective study at a large community radiation therapy center assessed this finding in the nonprotocol setting. The study population consisted of 86 patients treated with primary radiation therapy between 1982 and 1992; 62 of them also received chemotherapy. The overall probability of survival was 39% and 13% at 12 and 24 months respectively. Patients receiving chemotherapy had a significantly (p = .018) longer survival (44% versus 25% at 12 months). Results confirm the Study Group's findings and suggest that they be applied to the community setting.

On the mechanism for enhancement of tumor radiation to hyperbaric oxygen in sodium pentobarbital anesthetized rodents.

Pentobarbital anesthesia has been observed to increase markedly the effectiveness of respiration of oxygen at 3 atmospheres of pressure absolute to increase the response of early generation isotransplants of C3H mouse tumors to two-dose irradiation. A possible mechanism of this phenomenon is suppression of oxygen utilization by the pentobarbital and hence increasing mean pO2 and oxygen diffusion lengths. Measurements of QO2 of suspension of MCaIV and FSaII cells from freshly excised tumor tissue have been measured for cells suspended in PBS, Hank's buffered with HEPES +/- glutamate. The oxygen utilization by these tumor cells in vitro (when measured at congruent to 10 minutes after excision) is low, viz. 1 nmole/min/mg protein as compared with 6-9 nmoles/min/mg protein for established cell lines cultured in vitro. The suppression of QO2 by 2mM pentobarbital is less than 10%. This is a concentration of pentobarbital that is judged to be close to that which obtains in the tissues of the animals in the radiation response assays. Pentobarbital at .2mM did not change the cell survival characteristics of Chinese V79 cell spheroids irradiated in vitro. The results of these experiments do not indicate the suppression of oxygen utilization is an important contributor to the observed phenomenon of the increased response of tumors irradiated in mice respiring oxygen at high pressure. The role of hypothermia produced by the anesthesia is under further study.