[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.

[Predictive factors of pathological complete response after neoadjuvant chemoradiotherapy for middle-low rectal cancer].

Objective: To explore the predictive factors of pathological complete response (pCR) after neoadjuvant chemoradiotherapy for middle-low rectal cancer. Methods: A case-control study was conducted. The inclusion criteria were as follows: (1) colonoscopy, digital examination or magnetic resonance imaging (MRI) showed a distance from the lower edge of the tumor to the dentate line of no more than 10 cm; (2) complete clinicopathological data were available; (3) preoperative biopsy revealed adenocarcinoma; (4) preoperative pelvic MRI or endorectal ultrasonography was performed; (5) no distant metastasis was found. Exclusion criteria: (1) preoperative radiotherapy and chemotherapy were not administrated according to the standard; (2) simultaneous multiple primary cancer and familial adenomatous polyposis were observed. According to the above criteria, clinicopathological data of 245 patients with middle-low rectal cancer undergoing preoperative neoadjuvant chemoradiotherapy in Changhai Hospital of Navy Medical University from January 2012 to December 2019 were retrospectively collected. Univariate analysis and multivariate logistic analysis were used to identify the clinical factors predicting pCR. pCR is defined as complete disappearance of cancer cells under the microscope in cancer specimens (including lymph nodes) after neoadjuvant chemoradiotherapy. Results: A total of 72 patients with pCR were enrolled in this study. Univariate analysis showed that preoperative T stage, tumor circumference, tumor morphology, carbohydrate antigen (CA) 19-9, interval between the end of neoadjuvant therapy and operation were associated with pCR (all P<0.05). The above 5 variables were included in multivariate logistic analysis and the results revealed that the T stage (OR=5.743, 95% CI: 2.416-13.648, P<0.001), tumor circumference (OR=7.754, 95% CI: 3.822-15.733, P<0.001), tumor morphology (OR=0.264, 95% CI: 0.089-0.786, P=0.017) and the interval between the end of neoadjuvant therapy and operation (OR=0.303, 95% CI: 0.147-0.625, P=0.001) were independent predictive factors of pCR, while CA 19-9 level was not an independent factor (OR=1.873, 95% CI:0.372-9.436, P=0.447). Conclusion: By knowing the clinical features of preoperative T stage, tumor circumference, tumor morphology and the interval between neoadjuvant chemoradiotherapy and operation, patients with higher likelyhood of pCR after neoadjuvant chemoradiotherapy may be identified.

Retrospective study of the functional and oncological outcomes of conformal sphincter preservation operation in the treatment of very low rectal cancer.

BACKGROUND: Conformal sphincter preservation operation (CSPO) is a new surgical procedure for very low rectal cancers (within 4-5 cm from the anal verge). CSPO preserves more of the dentate line and distal rectal wall and also avoids injuring nerves in the intersphincteric space, resulting in satisfactory anal function after resection. The aim of this study was to analyze the short-term surgical results and long-term oncological and functional outcomes of CSPO. METHODS: Consecutive patients with very low rectal cancer, who had CSPO between January 2011 and October 2018 at Changhai Hospital, Shanghai were included. Patient demographics, clinicopathological features, oncological outcomes and anal function were analyzed. RESULTS: A total of 102 patients (67 men) with a mean age of 56.9 ± 10.8 years were included. The median distance of the tumor from the anal verge was 3 (IQR, 3-4) cm. Thirty-five patients received neoadjuvant chemoradiation (nCRT). The median distal resection margin (DRM) was 0.5 (IQR, 0.3-0.8) cm. One patient had a positive DRM. All circumferential margins were negative. There was no perioperative mortality. The postoperative complication rate was 19.6%. The median duration of follow-up was 28 (IQR, 12-45.5) months. The local recurrence rate was 2% and distant metastasis rate was 10.8%. The 3-year overall survival and disease-free survival rates were 100% and 83.9%, respectively. The mean Wexner incontinence and low anterior resection syndrome scores 12 months after ileostomy reversal were 5.9 ± 4.3, and 29.2 ± 6.9, respectively. CONCLUSIONS: For patients with very low rectal cancers, fecal continence can be preserved with CSPO without compromising oncological results.

Correlation of RGS4 and P16 expressions with pediatric nephroblastoma and its significance on prognosis.

OBJECTIVE: To investigate the correlation of regulator of G-protein signaling 4 (RGS4) and P16 expressions with pediatric nephroblastoma and its significance on prognosis. PATIENTS AND METHODS: A total of 80 children with primary nephroblastoma who underwent surgical resection in our hospital from March 2009 to March 2012 were selected as objects of study. The expressions of RGS4 and P16 in cancer and cancer-adjacent tissues of patients were detected by reverse transcription-polymerase chain reaction (RT-PCR), Western blot and immunohistochemistry. All patients were followed up for 5 years. The relationship of RGS4 and P16 to nephroblastoma staging and patients' prognosis was analyzed. RESULTS: The results of RT-PCR and Western blot displayed that the expressions of RGS4, P16 mRNA and protein in cancer tissue, were significantly lower than those in cancer-adjacent tissue (p < 0.05). Immunohistochemistry result revealed that the positive rates of RGS4 and P16 in cancer tissue were distinctly lower than those in cancer-adjacent tissue (76.54% vs. 34.32%, p < 0.05). RGS4 and P16 protein expressions were not associated with tumor, node metastasis (TNM) and pathological typing of nephroblastoma, but they were lowly expressed in patients with high metastasis (p < 0.05). The expressions of RGS4 and P16 were absent in pediatric nephroblastoma, and overall survival (OS) was significantly reduced (p < 0.05). CONCLUSIONS: The absence of RGS4 and P16 in pediatric nephroblastoma tissue is correlated with poor prognosis of patients. RGS4 and P16 are of significance for the prognosis of pediatric nephroblastoma.