First discovered in 1997 the torque teno virus (TTV) can be found in the vast majority of the human population throughout their lifetime. The TTV levels correlate with infectious diseases and organ rejection and are therefore currently being investigated as a tool to optimize the management of patients after solid organ transplantation (SOT). While TTV levels are already tested to guide immunosuppressive therapy its significance for oncologic patients is unclear. In recent years immune checkpoint inhibitors (ICIs) are increasingly implemented in multimodal therapy approaches for patients with non-small-cell lung cancer (NSCLC). Since ICI and TTV levels depend on T-cell function, the TTV load may be a relevant biomarker for the treatment response as well as complication risk after ICI therapy. Current standard imaging using PERCIST and RECIST criteria is prone to misinterpretation of treatment response of ICI therapy due to pseudoprogression and nodal immune flaring. This study aims to prospectively analyze TTV levels in NSCLC patients before, during and after neoadjuvant chemo-immunotherapy and correlate inter- and intraindividual changes in TTV levels with response rates observed on PET/CT restaging and histopathological response rates as well as postoperative outcome.

Inclusion Criteria:

- Histologically or cytologically verified NSCLC stage II-IV (OMD) according to UICC TNM8 edition considered operable in curative intent after neoadjuvant systemic therapy containing immune checkpoint inhibition by local multidisciplinary tumor board (MDT) decision.

ECOG < or = 1 Staging with PET/CT and cMRI/CCT Written informed consent

Exclusion Criteria:

-

Male and female patients aged > 18 years. Women of childbearing potential are eligible and must provide a negative serum or urine pregnancy test and follow instructions for contraception.

IPD will be shared with scientific institutions upon reasonable request.