Data Source
The data of this study derive from the clinical diagnosis and treatment
for cervical cancer in mainland China (Four C) database, a cervical
cancer-specialized disease database (n=46,313) that covers consecutive
patients with cervical cancer in 37 hospitals in mainland China treated
between January 2004 and December 2016. The Ethics Committee of Nanfang
Hospital, Southern Medical University, approved this retrospective study
(ethics number NFEC-2017-135). Written informed consent was waived by
the ethics committee, as the information of human medical documents was
retrospectively gathered and analyzed and patient data were
unidentifiable in this study. The identifier of the clinical trial is
CHiCTR1800017778 (International Clinical Trials Registry Platform Search
Port,http://apps.who.int/trialsearch/).
Using standardized data collection and quality control procedures,
trained gynecological oncology staff collected the clinical data from
patient files and the medical record management system in the hospitals.
The details of the data sources and methods were the same those as
previously reported12, 13. For patients undergoing
surgical treatment, the collected data, including demographic details,
preoperative examination results, surgical information, pathological
results, preoperative and postoperative adjuvant treatment details,
complications, hospitalization time, expenses, and follow-up, contained
almost all the information during the treatment of cervical cancer. In
this database, the FIGO stage was recorded and corrected by tumor size
according to the FIGO 2009 staging system. Tumor size was evaluated by
pathological records. To ensure the accuracy of the collected data, two
uniformly trained staff members used EpiData software (EpiData
Association, Odense M, Denmark) to input and proofread the same data
from each hospital.
All follow-up procedures were carried out by trained gynecological
oncology staff at each center to keep the patients’ personal data
confidential and to provide disease management guidance. The follow-up
information, including survival status, time of death, recurrence time,
recurrence site, and treatment after recurrence, was gathered through
the return visit system or telephone follow-up. Oncological outcomes
were assessed according to the recorded information, and the last day of
the return visit or telephone follow-up was defined as the last
follow-up. The follow-up rate of oncological outcomes in this database
is 72·7%.