Follow-up
DISEASE PROGRESSION, RECURRENCE
Patients who continued to surgery after completion of ≥ 1 cycle of avelumab will have regular follow-up visits every 3 months until 2 years after study inclusion, including blood withdrawal and radiological examination. In case of a recurrence or disease progression, a diagnostic confirmatory tissue biopsy is performed. In case of disease progression, all subsequent treatment modalities applied will be recorded until 2 years after surgery. In addition, included patients who did not receive avelumab will be followed as well as part of the intention-to-treat analysis.