Sarah Verhoeff

117 [89Zr]Zr-DFO-avelumab PET/CT in early stage NSCLC patients Avelumab treatment and response In total 19 out of 20 patients with early-stage NSCLC started avelumab treatment. One patient showed rapid disease progression before avelumab initiation and induction chemotherapy was preferred over avelumab. Figure 1 shows the follow-up of patients after avelumab initiation. 17 (89%) patients received two cycles of neo-adjuvant avelumab and two patients only one cycle of avelumab due to adverse events. Treatment responses of patients with stage IV NSCLC are reported in Supplementals. Figure 1. Swimmer plot. Each bar reflects a single patient with early-stage NSCLC from study entry. The most frequent reported treatment-related adverse events during avelumab treatment were respiratory complains (e.g., cough, dyspnea) and fatigue (suppl, Table 1). Due to grade 2 adverse events, two patients with neo-adjuvant avelumab treatment received only one cycle of avelumab. 18 of 19 (95%) patients underwent surgical resection after neo-adjuvant avelumab treatment. One patient received curative radiotherapy instead of surgery because the location of the tumor was associated with a higher risk of surgical complications. All surgical procedure were performed as planned, no conversions from video-assisted thoracotomy to open procedures occurred. Pathological response Pathological response was evaluated for 18 patients who underwent surgery after neo-adjuvant avelumab treatment (Figure 2). Major pathological response was observed in two patients. 6