Figure 2.

Tumor regressed after the combined treatment with RT and pembrolizumab. A. On June 25, 2016 (a month after starting treatment with RT), an enhanced CT scan showed the dramatically decreased volumes of tumors, compared with the images before combined treatment (May 18, 2016), not only in irradiated field but also in non-irradiated fields; more importantly, the CT scan images on July 27, 2016 demonstrated that all metastases, including the mass in the RT field and other metastatic lesions out of the RT fields, had completely resolved, consistent with a systemic complete response by RECIST criteria. B. The first detection of ctDNA abundance in May 18, 2016 showed 3.77% (ctDNA abundance = ctDNA in peripheral blood / total free DNA in peripheral blood); there was a remarkable decrease of ctDNA abundance (2.28%) measured in June 23, 2016; and only 0.38% ctDNA abundance could be detected in Sep. 14, 2016.