TETs	Thymic epithelial tumors
ATTs	Advanced thymic tumors
IT	Induction therapy
RR	Radiological response
PFS	Progression-free survival
OS	Overall survival
PR	Partial response
CR	Complete response
PET	Positron emission tomography
RECIST	Response Evaluation Criteria in Solid Tumors
WHO	World Health Organization
NOS	Newcastle–Ottawa Scale
CI	Confidence interval
SE	Standard error
NSCLC	Non-small cell lung cancer
PRISMA	Preferred Reporting Items for Systematic Reviews and Meta-Analyses
PROSPERO	Prospective Register of Systematic Reviews