[Clinical features and prognosis of anastomotic leak after anterior resection for rectal cancer following neoadjuvant chemoradiotherapy]

Objective: To explore clinical features and prognosis of anastomotic leak (AL) after anterior resection following neoadjuvant chemoradiotherapy for rectal cancer patients. Methods: A retrospective cohort study was performed. Data were retrieved from colorectal cancer database of the Sixth Affiliated Hospital, Sun Yat-sen University. The clinical data of 470 patients with rectal cancer who underwent anterior resection after neoadjuvant chemoradiotherapy at our department from September 2010 to December 2018 were enrolled. Clinical features and outcome of postoperative AL were analyzed. The primary outcomes were the short-term and long-term incidence and severity of AL (ISREC grading standard was adopted). The secondary outcomes were the prognostic indicators of AL, including the secondary chronic presacral sinus, anastomotic stenosis and persistent stoma. Patients received regular follow-up every 3-6 months after surgery, including physical examination, blood test, colonoscopy and image; those received follow-up once a year after postoperative 2-year; those who did not return to our hospital received telephone follow-up. Data of this study were retrieved up to January 2020. Univariate χ(2) test and multivariate logistic analysis were used to identify risk factors of AL and prognostic factors of persistent stoma. Results: There were 331 males (70.4%) with the average age of (53.5±11.6) years. Distance from tumor to anal verge ≤ 5 cm was found in 228 (48.5%) patients. The diverting stoma was performed in 440 (93.6%) patients. After a median follow-up of 28 months, AL was found in 129 (27.4%) patients, including 67 (14.3%) patients with clinical leak (ISREC grade B-C). The median time for diagnosis of AL was 70 days (2-515 days) after index surgery. Common symptoms included sacrococcygeal pain (27.9%, 36/129), purulent discharge through anus (25.6%, 33/129), and rectal irritation (17.8%, 23/129). Sixty five point one percent (84/129) of the defect site was at the posterior wall of the anastomosis. Transanal incision and drainage or lavage (27.9%, 36/129) and percutaneous drainage under ultrasound or CT (17.1%, 22/129) were the most common management. Chronic presacral sinus tract could not be evaluated in 12 patients because imaging was performed more than 1 year after the operation. Evaluation beyond 1 year showed that 73 of 458 eligible patients (15.9%) were found with chronic presacral sinus, accounting for 62.4% (73/117) of patients with AL; 69 of 454 (15.2%) were diagnosed with anastomotic stenosis, of whom 49 were secondary to AL; 59 of 470 (12.6%) had persistent stoma due to AL. Univariate analysis showed that male, operative duration > 180 minutes, intraoperative blood loss >150 ml, and pelvic radiation injury were associated with AL (all P<0.05). Multivariate analysis showed that male (OR=1.72, 95% CI: 1.04-2.86, P=0.036), intraoperative blood loss > 150 ml (OR=1.82, 95% CI: 1.11-2.97, P=0.017), and pelvic radiation injury (OR=4.90, 95% CI: 3.09-7.76, P<0.001) were independent risk factors of AL after anterior resection. For patients with AL, clinical leak (ISREC grade B-C) (OR=9.59, 95% CI: 3.73-24.69, P<0.001), age ≤55 years (OR=3.35, 95% CI: 1.35-8.30, P=0.009), distance from tumor to anal verge ≤ 5 cm (OR=3.33, 95% CI: 1.25-8.92, P=0.017), and pelvic radiation injury (OR=3.29, 95% CI: 1.33-8.14, P=0.010) were independent risk factors of persistent stoma. Conclusions: AL after anterior resection following neoadjuvant chemoradiotherapy for rectal cancer patients is common. Among patients with AL, the proportion of those needing persistent stoma is high. Pelvic radiation injury is significantly associated with occurrence of AL and subsequent persistent stoma. Sphincter-preserving surgery for rectal cancer should be selectively used based on the risk of pelvic radiation injury, which is beneficial to reduce the incidence of AL and improve the quality of life.

A novel mechanism driving poor-prognostic gastric cancer: overexpression of the transcription factor Krüppel-like factor 16 promotes growth and metastasis of gastric cancer through regulating the Notch pathway

Gastric cancer (GC) is one of the most common malignant tumors worldwide and has high rates of morbidity and mortality. This study investigated the role of Krüppel-like factor 16 (KLF16) in GC. Real-time polymerase chain reaction, Western blotting, and immunohistochemistry were used to examine the expression of KLF16 in gastric cells and tissues. Gene overexpression and silencing were applied to study the involvement of KLF16 in GC cell growth and metastasis along with its underlying mechanism. The results indicate that KLF16 overexpression is significantly associated with nodal status, distant metastasis, staging, degree of differentiation, vascular invasion, and patient survival. Multivariate Cox proportional hazards regression model analysis revealed that the overexpression of KLF16 is an independent prognostic biomarker of GC. The in vitro study revealed that up-regulated KLF16 accelerates cell growth and metastasis, whereas the inhibition of KLF16 suppresses these cellular activities. The results of an animal study also indicated that the overexpression and silencing of KLF16 accelerate and repress xenograft proliferation and metastasis. Further studies of affected cell growth and metastasis revealed that KLF16 modulates the cell cycle and epithelial-mesenchymal transition through transcriptional regulation of microfibrillar-associated protein 5. Collectively, these results reveal that KLF16 overexpression is a potential prognostic biomarker and therapeutic target for the treatment of GC.

Aberrant Expression of NCAPG is Associated with Prognosis and Progression of Gastric Cancer

Introduction

Gastric cancer (GC), one of the most prevalent malignancies, is the third-leading cause of cancer-related deaths globally. The aim of this study is to investigate the involvement of non-structural maintenance of chromosomes condensin I complex subunit G (NCAPG) in the prognosis of GC.

Methods

Western blotting and immunostaining were employed to measure the NCAPG level in gastric tissues and cells. Kaplan–Meier analysis was applied to analyze the prognostic value of NCAPG in GC. RNA interference was applied to investigate the influence of the NCAPG silencing on GC cell growth and spread.

Results

NCAPG overexpression was associated with several clinicopathologic characteristics, including nodal status (P = 0.0378), distant metastasis (P = 0.0088), staging (P = 0.0230), vascular invasion (P = 0.0012), and disease-free survival (P = 0.004). Kaplan–Meier analysis revealed that NCAPG overexpression was positively correlated to poor GC patients disease-free and overall survival (P = 0.004 and P < 0.001, respectively). Univariate Cox regression analysis showed that the overexpression of NCAPG was a prognostic biomarker of GC (P = 0.005). In cultured GC cells, the knockdown of NCAPG suppressed cell proliferation, migration and invasion. Meanwhile, further studies revealed that the NCAPG silencing induces the G0/G1 cell cycle arrest and accordingly represses cell division. Finally, Western blotting showed that NCPAG knockdown dysregulated cell cycle- and epithelial–mesenchymal transition-related molecules.

Conclusion

Overall, the results reveal that NCAPG overexpression is a candidate prognostic biomarker and potential therapeutic target in GC.

[Analysis on operational safety of chronic radiation intestinal injury]

Objective: To investigate the safety and efficacy of surgical treatment for chronic radiation intestinal injury. Methods: A descriptive cohort study was performed. Clinical data of 73 patients with definite radiation history and diagnosed clinically as chronic radiation intestinal injury, undergoing operation at Department of Colorectal Surgery, the Sixth Affiliated Hospital of Sun Yat-sen University from January 1, 2012 to February 28, 2019, were reviewed and analyzed retrospectively. Patients did not undergo operation or only received adhesiolysis were excluded. All the patients had preoperative examination and overall evaluation of the disease. According to severity of intestinal obstruction and patients' diet, corresponding nutritional support and conservative treatment were given. Surgical methods: The one-stage bowel resection and anastomosis was the first choice for surgical treatment of chronic radiation intestinal injury. Patients with poor nutritional condition were given enterostomy and postoperative enteral nutrition and second-stage stoma closure and intestinal anastomosis if nutritional condition improved. For those who were unable to perform stoma closure, a permanent stoma should be performed. Patients with severe abdominal adhesion which was difficult to separate, enterostomy or bypass surgery after adhesiolysis would be the surgical choice. For patients with tumor metastasis or recurrence, enterostomy or bypass surgery should be selected. Observation parameters: the overall and major (Clavien-Dindo grades III to V) postoperative complication within 30 days after surgery or during hospitalization; mortality within postoperative 30 days; postoperative hospital stay; time to postoperative recovery of enteral nutrition; time to removal of drainage tube. Results: Of the 73 patients who had been enrolled in this study, 10 were male and 63 were female with median age of 54 (range, 34-80) years. Preoperative evaluation showed that 61 patients had intestinal stenosis, 63 had intestinal obstruction, 11 had intestinal perforation, 20 had intestinal fistula, 3 had intestinal bleeding, and 6 had abdominal abscess, of whom 64(87.7%) patients had multiple complications. Tumor recurrence or metastasis was found in 15 patients. A total of 65(89.0%) patients received preoperative nutritional support, of whom 35 received total parenteral nutrition and 30 received partial parenteral nutrition. The median preoperative nutritional support duration was 8.5 (range, 6.0-16.2) days. The rate of one-stage intestine resection was 69.9% (51/73), and one-stage enterostomy was 23.3% (17/73). In the 51 patients undergoing bowel resection, the average length of resected bowel was (50.3±49.1) cm. Among the 45 patients with intestinal anastomosis, 4 underwent manual anastomosis and 41 underwent stapled anastomosis; 36 underwent side-to-side anastomosis, 5 underwent end-to-side anastomosis, and 4 underwent end-to-end anastomosis. Eighty postoperative complications occurred in 39 patients and the overall postoperative complication rate was 53.4% (39/73), including 39 moderate to severe complications (Clavien-Dindo grade III-V) in 20 patients (27.4%, 20/73) and postoperative anastomotic leakage in 2 patients (2.7%, 2/73). The mortality within postoperative 30 days was 2.7% (2/73); both patients died of abdominal infection, septic shock, and multiple organ failure caused by anastomotic leakage. The median postoperative hospital stay was 13 (11, 23) days, the postoperative enteral nutrition time was (7.2±6.9) days and the postoperative drainage tube removal time was (6.3±4.2) days. Conclusions: Surgical treatment, especially one-stage anastomosis, is safe and feasible for chronic radiation intestine injury. Defining the extent of bowel resection, rational selection of the anatomic position of the anastomosis and perioperative nutritional support treatment are the key to reduce postoperative complications.

[Pathological insights of radiotherapy-related damage to surgical margin after preoperative radiotherapy in patients with rectal cancer]

Objective: To investigate the effect of irradiation to anastomosis from preoperative radiotherapy for patients with rectal cancer by studying the pathological changes. Methods: In this retrospective study, patients enrolled in the FOWARC study from January 2011 to July 2014 in the Sixth Affiliated Hospital of Sun Yat-Sen University were included. In the FOWARC study, enrolled patients with local advanced rectal cancer were randomly assigned to receive either neoadjuvant chemo-radiotherapy or chemotherapy. Among these patients, 23 patients were selected as radiation proctitis (RP)group, who fulfilled these conditions: (1) received neoadjuvant chemo-radiotherapy followed by sphincter-preserving surgery; (2) developed radiation proctitis as confirmed by preoperative imaging diagnosis; (3) had intact clinical samples of surgical margins. Twenty-three patients who had received neoadjuvant chemo-radiotherapy but without development of radiation proctitis were selected as non-radiation proctitis (nRP) group. Meanwhile, 23 patients received neoadjuvant chemotherapy only were selected as neoadjuvant chemotherapy (CT) group. Both nRP and CT cases were selected by ensuring the basic characteristics such as sex, age, tumor site, lengths of proximal margin and distal margin all maximally matched to the RP group. Both proximal and distal margins were collected for further analysis for all selected cases. Microscopy slices were prepared for hematoxylin & eosin staining and Masson staining to show general pathological changes, and also for immunohistochemistry with anti-CD-34 as primary antibody to reveal the microvessel. Microvessel counting in submucosal layer and proportion of macrovessel with stenosis were used to evaluate the blood supply of the proximal and distal end of anastomosis. A modified semi-quantitative grading approach was used to evaluate the severity of radiation-induced injury. Either ANOVA analysis, Kruskal-Wallis rank-sum test or χ(2) test was used for comparison among three groups, and Mann-Whitney U test was used for comparison between two groups. Results: Compared to group of neoadjuvant chemotherapy only, patients receiving neoadjuvant chemo-radiotherapy had lower microvessel count in both proximal and distal margins (M(Q(R)): proximal, 25.5 (19.6) vs. 50.0 (25.0), Z=3.915, P=0.000; distal, 20.5 (17.5) vs. 49.0 (28.0), Z=3.558, P=0.000), higher proportions of macrovessel with stenosis (proximal, 9.5% (23.8%) vs. 0, Z=3.993, P=0.000; distal, 11.5%(37.3%) vs. 0 (2.0%), Z=2.893, P=0.004), higher histopathologic score (proximal, 4.0 (2.0) vs. 1.0 (2.0), Z=6.123, P=0.000; distal, 5.0 (3.0) vs. 2.0 (1.0), Z=4.849, P=0.000). In patients receiving neoadjuvant chemo-radiotherapy, compared to nRP group, RP group had lower microvessel count in both proximal and distal margins (proximal, 19.0 (23.0) vs. 30.4 (38.0), Z=2.845, P=0.004; distal, 19.0 (13.0) vs. 30.0(29.1), Z=2.022, P=0.043), higher proportions of macrovessel with stenosis (proximal, 23.0% (40.0%) vs. 0(11.0%), Z=3.248, P=0.001; distal, 27.0% (45.0%) vs. 3.0% (19.0%), Z=2.164, P=0.030). Rate of anastomotic leakage for CT, nRP and RP group were 8.7% (2/23), 30.4% (7/23), and 52.2% (12/23), and the differences among three groups were statistically significant (χ(2)=10.268, P=0.007). Conclusion: Radiation-induced injury existed on both margins of the resected rectal site after preoperative radiotherapy, and those diagnosed as radiation proctitis had more severe microvascular injury.