Follow up
Similar follow-up protocol was used at each center. The patients were
seen initially 1 month after surgery, then every 3 months for the first
year, every 6 months for the second year and annually thereafter. The
follow-up visits consisted of a physical examination and laboratory
studies. Imaging modalities including chest radiography, abdominal CT or
ultrasonography were applied at least every 6 months or when clinically
indicated.
The primary outcome measures in this study were overall survival (OS),
cancer-specific survival (CSS), recurrence-free survival (RFS),
metastasis-free survival (MFS) and disease free survival (DFS). Duration
of follow-up was the time from surgery to the date of death or last
clinic visit.