Negativation of PD-L1 Postoperatively in Initially Inoperable Stage III Non-Small Cell Lung Cancer Treated with Pembrolizumab: Two Case Reports

Stage III non-small cell lung cancer is a border line stage between localized and metastatic disease. PDL-1 is gaining an important role in the therapeutic arsenal of lung cancer, the most frequent cancer worldwide. We report for the first time a negativation of PDL-1 status in 2 cases of stage IIIA NSCLC with conversion to operable disease after using immunotherapy. The first patient was a 59-year old female diagnosed incidentally to have stage IIIA inoperable NSCLC that was treated with combination chemo-immunotherapy, and converted to operable disease with a negative PD-L1 in the postoperative setting. The second case is that of a 56-year old male that also had an inoperable stage IIIA NSCLC treated with chemotherapy first line followed by pembrolizumab at progression, then operated after surgical conversion, with negative PD-L1 postoperatively. In front of these findings, further work should be done to elucidate if the reverse of the PDL-1 status and the conversion to operability were due to the use of immunotherapy or to an incidental finding. If confirmed, it may have a therapeutic impact.