The risk of postoperative complications is higher in stage I-III colorectal cancer patients with previous abdominal surgery: a propensity score matching analysis.

PURPOSE: The aim of this study is to investigate whether previous abdominal surgery (PAS) affected stage I-III colorectal cancer (CRC) patients who underwent radical resection. METHODS: Stage I-III CRC patients who received surgery at a single clinical center from Jan 2014 to Dec 2022 were retrospectively included in this study. Baseline characteristics and short-term outcomes were compared between the PAS group and the non-PAS group. Univariate and multivariate logistic regression analyses were used to find risk factors for overall complications and major complications. A 1:1 ratio propensity score matching (PSM) was used to minimize the selection bias between the two groups. Statistical analysis was performed using SPSS (version 22.0) software. RESULTS: A total of 5895 stage I-III CRC patients were included according to the inclusion and exclusion criteria. The PAS group had 1336 (22.7%) patients, and the non-PAS group had 4559 (77.3%) patients. After the PSM, there were 1335 patients in each group, and no significant difference was found in all baseline characteristics between the two groups (P > 0.05). After comparing the short-term outcomes, the PAS group had a longer operation time (before PSM, P < 0.01; after PSM, P < 0.01) and more overall complications (before PSM, P = 0.027; after PSM, P = 0.022) whether before or after PSM. In univariate and multivariate logistic regression analyses, PAS was an independent risk factor for overall complications (univariate analysis, P = 0.022; multivariate analysis, P = 0.029) but not for major complications (univariate analysis, P = 0.688). CONCLUSION: Stage I-III CRC patients with PAS might experience longer operation time and have a higher risk of postoperative overall complications. However, it did not appear to significantly affect the major complications. Surgeons should take steps to improve surgical outcomes for patients with PAS.

DNA methylation dynamics in the rat EGF gene promoter after partial hepatectomy.

Epidermal growth factor (EGF), a multifunctional growth factor, is a regulator in a wide variety of physiological processes. EGF plays an important role in the regulation of liver regeneration. This study was aimed at investigating the methylation level of EGF gene throughout liver regeneration. DNA of liver tissue from control rats and partial hepatectomy (PH) rats at 10 time points was extracted and a 354 bp fragment including 10 CpG sites from the transcription start was amplified after DNA was modified by sodium bisulfate. The result of sequencing suggested that methylation ratio of four CpG sites was found to be significantly changed when PH group was compared to control group, in particular two of them were extremely striking. mRNA expression of EGF was down-regulated in total during liver regeneration. We think that the rat EGF promoter region is regulated by variation in DNA methylation during liver regeneration.