1.1 Patients
This retrospective analysis was carried out in 2020, when the inpatient records of locally advanced rectal cancer patients who treated with preoperative chemoradiotherapy in the first affiliated hospital of Kunming medical university were screened from January 1, 2014 to December 31, 2019 and the patients' information including identity number, name, age, gender, ECOG PS , telephone number, clinical TNM stage, tumor location, histology, MRI information (including cTNM stage, CRM, EMVI) and survival information were obtained and analyzed. For there was not any obtained data could identify the involved patient, the data collecting and the follow-up were approved by the ethics committee of the first affiliated hospital of Kunming medical university .
1.1.1 Inclusion criteria
Patients aged from 18-80 years; ECOG 0-2; proved to be middle-low rectum adenocarcinoma; with clinical stage T3-4 or TanyN+(International Union Against Cancer, version 8); without other fatal diseases like severe cardiac or pulmonary diseases; without previously treatment; treated with preoperative concurrent chemoradiotherapy and radical operation 8-12 weeks later; with normal liver, renal and bone marrow function and complete follow-up information.were included.
1.1.2 Exclusion criteria
Patients younger than 18 or older than 80; ECOG ≥3; without histology information, with severe diseases of cardiac, respiratory or other system; with abnormal liver, renal or bone marrow function; without complete chemoradiotherapy; without sequential operation or without complete follow-up information were excluded.
1.2 Treatment
The chemotherapy regimen was separately to administer Capecitabine(Xeloda, Roche) orally, (825mg/m2, twice a day, half an hour after diet, from Monday to Friday during radiotherapy), the radiotherapy was using IMRT technology and as to the clinical target volume, it was defined as the upper boundary was the lower edge of the L5 vertebral body, and the lower boundary was the lower edge of the tumor (3cm), including the anterior sacral soft tissue, drainage area of the internal iliac lymph node and the mesenteric region. Besides, according to the invasion and lymph node metastasis of the tumor, the external iliac, inguinal and common iliac lymph node regions were included if necessary, the important organs, such as small intestine, bladder and femoral head, were delineated and the total dose was 45-50.4Gy, 1.8-2.0Gy/ fraction, 5 fractions/week, and continued radiotherapy for 5-6 weeks. All the treatment including the chemoradiotherapy, and the subsequent therapy were performed according to the guidelines, such as the NCCN and ESMO guidelines.
Adverse effects were observed and graded according to the Common Terminology Criteria for Adverse Events (version 3.0), severe events were treated according to the clinical guidelines like NCCN guidelines, and the dose of capecitabine or radiotherapy could be adjusted by physicians according to the adverse effects if necessary. Subsequently, post-study treatment was given at the discretion of the physician and patient according to the guidelines.
1.3 Follow-up and Assessments
All enrolled patients’ information were gotten from the inpatient record system, all the selected patients were followed up by telephone for PFS, OS, responses and adverse events, and tumors assessments were performed via pathological information of operation and magnetic resonance imaging(MRI), confirmed through reviewing the data from picture archiving and communication system(PACS) and the hospital information system(HIS) by two experienced pathologists or radiologists, Among that, PFS was defined as the time from treatment beginning to the earliest occurrence of disease progression or death from any cause, especially, the data of patients who had not experienced progression or died at data cutoff would be censored at the last tumor assessment, while OS was assessed from the date of treatment beginning to the date of death as the result of any cause, or data were censored at the last date that the patient was confirmed to be alive. Tumor response according to RECIST 1.1 was assessed at baseline and 8 weeks after chemoradiotherapy. The process was similar to another research of us which was published on September 2015.[9]
1.4 Statistical Analysis
The primary end points were PFS and OS between PCR and non-PCR patients. single factor analysis for which were performed to explore the potential differences between groups with age (≤60 vs. >60), gender (male vs. female), PS (0-1 vs. 2), clinical T stage (T1-3 vs. T4), clinical N stage(N0-1 vs. N2) ,CRM invasion( CRM+ vs. CRM-), EMVI(EMVI+ vs. EMVI-), treatment reaction(downstage vs. not) by Kaplan-Meier survival analysis and log-rank test. Then, the cox-regression analysis were done to identify the interested factors and adjust the infection of the other confounding factors to the interested factors. Finally, statistical analyses were performed via using IBM ® SPSS® version 19.0.