- Pregnancy/lactation - The effects of the study drugs on the developing human fetus are unknown. For this reason and because bevacizumab, gemcitabine, and radiation therapy used in this trial are known to be teratogenic in animal studies, women and men of child-bearing potential must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) from the time of study entry until 6 months after the completion of study participation. Should a woman become pregnant or suspect she is pregnant while participating in this study, she should inform her treating physician immediately. A serum pregnancy test for those females of childbearing potential must be done prior to their receiving study drugs. Due to the combined effects of chemotherapy and radiation, breastfeeding is not allowed for 6 months after the completion of study participation.