[Advances in tumor regression patterns and safe distance of distal resection margin after neoadjuvant therapy for rectal cancer].

Neoadjuvant therapy has been widely applied in the treatment of rectal cancer, which can shrink tumor size, lower tumor staging and improve the prognosis. It has been the standard preoperative treatment for patients with locally advanced rectal cancer. The efficacy of neoadjuvant therapy for rectal cancer patients varies between individuals, and the results of tumor regression are obviously different. Some patients with good tumor regression even achieve pathological complete response (pCR). Tumor regression is of great significance for the selection of surgical regimes and the determination of distal resection margin. However, few studies focus on tumor regression patterns. Controversies on the safe distance of distal resection margin after neoadjuvant treatment still exist. Therefore, based on the current research progress, this review summarized the main tumor regression patterns after neoadjuvant therapy for rectal cancer, and classified them into three types: tumor shrinkage, tumor fragmentation, and mucin pool formation. And macroscopic regression and microscopic regression of tumors were compared to describe the phenomenon of non-synchronous regression. Then, the safety of non-surgical treatment for patients with clinical complete response (cCR) was analyzed to elaborate the necessity of surgical treatment. Finally, the review studied the safe surgical resection range to explore the safe distance of distal resection margin.

[A prospective cohort study on the clinical value of pelvic peritoneal reconstruction in laparoscopic anterior resection for middle and low rectal cancer].

Objective: To investigate the safety and efficacy of pelvic peritoneal reconstruction and its effect on anal function in laparoscopy-assisted anterior resection of low and middle rectal cancer. Methods: A prospective cohort study was conducted. Consecutive patients with low and middle rectal cancer who underwent laparoscopy-assisted transabdominal anterior resection at Naval Military Medical University Changhai Hospital from February 2020 to February 2021 were enrolled. Inclusion criteria: (1) the distance from tumor to the anal verge ≤10 cm; (2) laparoscopy-assisted transabdominal anterior resection of rectal cancer; (3) complete clinical data; (4) rectal adenocarcinoma diagnosed by postoperative pathology. Exclusion criteria: (1) emergency surgery; (2) patients with a history of anal dysfunction or anal surgery; (3) preoperative diagnosis of distant (liver, lung) metastasis; (4) intestinal obstruction; (5) conversion to open surgery for various reasons. The pelvic floor was reconstructed using SXMD1B405 (Stratafix helical PGA-PCL, Ethicon). The first needle was sutured from the left anterior wall of the neorectum to the right. Insertion of the needle was continued to suture the root of the sigmoid mesentery while the Hemo-lok was used to fix the suture. The second needle was started from the beginning of the first needle, after 3-4 needles, a drainage tube was inserted through the left lower abdominal trocar to the presacral space. Then, the left peritoneal incision of the descending colon was sutured, after which Hemo-lok fixation was performed. The operative time, perioperative complications, postoperative Wexner anal function score and low anterior resection syndrome (LARS) score were compared between the study group and the control group. Three to six months after the operation, pelvic MRI was performed to observe and compare the pelvic floor anatomical structure of the two groups. Results: A total of 230 patients were enrolled, including 58 who underwent pelvic floor peritoneum reconstruction as the study group and 172 who did not undergo pelvic floor peritoneum reconstruction as the control group. There were no significant differences in general data between the two groups (all P>0.05). The operation time of the study group was longer than that of control group [(177.5±33.0) minutes vs. (148.7±45.5) minutes, P<0.001]. There was no significant difference in the incidence of perioperative complications (including anastomotic leakage, anastomotic bleeding, postoperative pneumonia, urinary tract infection, deep vein thrombosis, and intestinal obstruction) between the two groups (all P>0.05). Eight cases had anastomotic leakage, of whom 2 cases (3.4%) in the study group were discharged after conservative treatment, 5 cases (2.9%) of other 6 cases (3.5%) in the control group were discharged after the secondary surgical treatment. The Wexner score and LARS score were 3.1±2.8 and 23.0 (16.0-28.0) in the study group, which were lower than those in the control group [4.7±3.4 and 27.0 (18.0-32.0)], and the differences were statistically significant (t=-3.018, P=0.003 and Z=-2.257, P=0.024). Severe LARS was 16.5% (7/45) in study group and 35.5% (50/141) in control group, and the difference was no significant differences (Z=4.373, P=0.373). Pelvic MRI examination 3 to 6 months after surgery showed that the incidence of intestinal accumulation in the pelvic floor was 9.1% (3/33) in study group and 46.4% (64/138) in control group (χ(2)=15.537, P<0.001). Conclusion: Pelvic peritoneal reconstruction using stratafix in laparoscopic anterior resection of middle and low rectal cancer is safe and feasible, which may reduce the probability of the secondary operation in patients with anastomotic leakage and significantly improve postoperative anal function.

[Discussion on the mechanism of anal sphincter insufficiency caused by radiotherapy in patients with rectal cancer].

At present, radiotherapy as an auxiliary treatment for rectal cancer is widely used in clinic. Although radiotherapy has significant effect on reducing tumor stage, improving anus preservation rate and less tumor recurrence, radiotherapy will damage the anal function and seriously affect the quality of life of patients. Anal sphincter plays an important role in anal function. There are three main damage effects of radiotherapy on anal sphincter: first, the increased deposition of collagen in internal anal sphincter (IAS); second, the destroyed ultrastructure of external anal sphincter (EAS); third, degenerative lesions of the perianal nerve. This article reviews these three points, in order to provide a certain theoretical basis for how to reduce the incidence of anal dysfunction caused by radiotherapy.

Expression of miR-217 and HIF-1α/VEGF pathway in patients with diabetic foot ulcer and its effect on angiogenesis of diabetic foot ulcer rats.

OBJECTIVE: To investigate the expression of miR-217 and HIF-1α/VEGF pathway in patients with diabetic foot ulcer (DFU) and its effect on angiogenesis in DFU rats. METHODS: The serum levels of miR-217, HIF-1α and VEGF were detected in DFU and simple diabetes mellitus (DM) patients, and healthy controls. DFU rat models were established and treated with miR-217 inhibitors and/or HIF-1α siRNA. The ulcer healing of DFU rats was observed. Besides, ELISA method was performed to detect the serum level of HIF-1α, VEGF and inflammatory factors, immunohistochemical (IHC) method to test the micro-vessel density (MVD), as well as qRT-PCR and Western blot to determine expressions of miR-217, HIF-1α, VEGF, VEGFR2, eNOS, MMP-2, and MMP-9 in tissues. RESULTS: The serum levels of miR-217 were up-regulated while HIF-1α and VEGF were down-regulated in DFU patients and rats when compared with DM and healthy controls (all P < 0.05). Dual-luciferase reporter gene assay confirmed that HIF-1α was the direct target gene of miR-217. DFU rats treated with miR-217 inhibitors had decreased foot ulcer area and accelerated ulcer healing, with significantly reduced inflammatory factors (IL-1ß, TNF-α and IL-6), as well as elevated HIF-1α and VEGF (all P < 0.05); meanwhile, they remarkably increased the MVD in foot dorsum wound tissues and the protein expressions of HIF-1α, VEGF, VEGFR2, eNOS, MMP-2, and MMP-9 (all P < 0.05). CONCLUSION: Inhibiting miR-217 could up-regulate HIF-1α/VEGF pathway to promote angiogenesis and ameliorate inflammation of DFU rats, thereby effectively advancing the healing of ulcerated area.