Data Collection and Follow-Up

We recorded the general data of all subjects at enrollment, including age, education level, occupation, annual income, body mass index, the number of sexual activities per month, tumor size, differentiation degree, FIGO stage, lymph node metastasis, and serum squamous cell carcinoma antigen (SCC-Ag). On the morning of the second day after enrollment, 10 mL fasting venous blood was drawn from the elbow of all included subjects and then placed in RNase-free Eppendorf tubes (1.5 mL). After centrifugation at 150 g for 10 min, the serum was separated and transferred into a special cryopreservation tube, followed by storage in a −80°C freezer. According to the FIGO clinical staging criteria for CC, patients with CC were classified as IB-II and III-IV, and tumor size was assigned as ≤4 cm and >4 cm. The level of SCC-Ag in the serum was measured using enzyme-linked immunosorbent assay kits (SBJ-H1977; SenBeiJia, Nanjing, China).

All enrolled CC patients underwent a 5-year clinical follow-up and the overall survival was computed in months from the date of the first operation to death. We excluded the patients who died due to diseases unrelated to CC or accidents. The follow-up information of all participants was updated every 3 months for the first 3 years and every 6 months in the 4th and 5th years. The death of the participants was reported and ascertained by the family and further verified by reviewing public records.