ARM II (INDUCTION COHORT): Patients receive anti-PD-L1 monoclonal antibody MPDL3280A IV over 30-60 minutes on day 1. Courses repeat every 3 weeks in the absence of disease progression or unacceptable toxicity. Beginning on day 1 of course 3, patients also undergo SAR 2-3 times per week (with a minimum of 40 hours and a maximum of 96 hours between fractions) over 1.5-2 weeks for a total of 5 fractions.