Diagnostic criteria
We confirmed post-molar GTN using 2021 FIGO criteria6. The presence of metastases in GTN patients was also detected using tools for investigation according to 2021 FIGO criteria6 as follows: (1) chest X-ray is appropriate for diagnosing lung metastases and can be used for counting the number of lung metastases to evaluate the risk score; (2) lung CT may not be used for the risk score; (3) liver metastases may be diagnosed using CT scan or MRI; (4) brain metastases may be diagnosed using MRI or CT scan.