Just found a study that discusses whether BAT does what you were talking about. In one study of 12 patients only one of them had tumor regression. Definitely something they could look into and maybe make it more widely available some day. They keep coming out with new treatments.

Here is a short synopsis of what they found

Given that tumor regression seems to occur in a minority of patients treated with BAT, identifying biomarkers that predict sensitivity could enhance the utility of this therapy.