Can FDG-PET after neoadjuvant chemotherapy plus nivolumab predict residual disease in non-small cell lung cancer?

Neoadjuvant therapy with nivolumab improves event-free survival (EFS) in patients with resectable non-small cell lung cancer, and a pathological complete response is a predictor of longer EFS. We assessed metabolic responses using 18F-fluorodeoxyglucose-positron emission tomography (FDG-PET) before and after neoadjuvant treatment to explore its surrogacy for pathological complete response (pCR). We describe three patients with squamous cell lung carcinoma who underwent neoadjuvant therapy with nivolumab plus chemotherapy, followed by surgery. In Cases 1 and 2, preoperative tumour response were PR per RECIST and demonstrated marked metabolic response on FDG-PET after neoadjuvant therapy, with both resected tumours showing a pCR. On the other hand, Case 3 showed a tumour response before surgery (PR per RECIST), however, the tumour, maintained FDG uptake (19.5 → 15.1), and the resected tumour remained residual cells (RVT, 15%). Thus, reduction of FDG uptake on FDG-PET can predict the pathological response to neoadjuvant therapy with nivolumab.