Radiation intestinal injury is one of the most common complications after abdominal pelvic radiotherapy, which seriously affects the quality of life for patients. According to the site of occurrence, it is divided into radiation enteritis, colitis and proctitis. The pathological characteristics of radiation intestinal injury mainly include interstitial fibrosis, mucosal edema, ulcers, and inflammatory cell infiltration, and significant vascular lesions as well. It showed telangiectasia and hemorrhage under endoscopy. Under ultrasound examination, it showed diffusive thickening of the intestinal wall and increased blood flow signals. In addition, it also has other features such as increased thickness of the distal sigmoid colon and rectal wall, and increased width of the presacral space. The key factors in the incidence and development of radiation intestinal injury include angiostatin, PDGF, CXCL16, etc. The mechanisms to be clarified include abnormally heightened angiostatin through which signal pathways specifically affect vascular endothelial cells and inhibit angiogenesis and vascular homeostasis, how CXCL16 expressed by macrophages interacting with receptor promotes the transformation of fibroblasts and vascular smooth muscle cells into myofibroblasts, etc. Therapy targeted on basics of vascular damage will be a promising field of radiation intestinal injury research.

Radiation intestinal injury is one of the most common complications after abdominal pelvic radiotherapy, which seriously affects the quality of life for patients. According to the site of occurrence, it is divided into radiation enteritis, colitis and proctitis. The pathological characteristics of radiation intestinal injury mainly include interstitial fibrosis, mucosal edema, ulcers, and inflammatory cell infiltration, and significant vascular lesions as well. It showed telangiectasia and hemorrhage under endoscopy. Under ultrasound examination, it showed diffusive thickening of the intestinal wall and increased blood flow signals. In addition, it also has other features such as increased thickness of the distal sigmoid colon and rectal wall, and increased width of the presacral space. The key factors in the incidence and development of radiation intestinal injury include angiostatin, PDGF, CXCL16, etc. The mechanisms to be clarified include abnormally heightened angiostatin through which signal pathways specifically affect vascular endothelial cells and inhibit angiogenesis and vascular homeostasis, how CXCL16 expressed by macrophages interacting with receptor promotes the transformation of fibroblasts and vascular smooth muscle cells into myofibroblasts, etc. Therapy targeted on basics of vascular damage will be a promising field of radiation intestinal injury research.

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 χ² 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 (χ²=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.

Objective:To preliminarily evaluate the feasibility and safety of laparoscopic Parks procedure for chronic radiation proctopathy (CRP).Methods:A descriptive cohort study was carried out. The clinical and follow-up data of 19 patients who received laparoscopic Parks procedure due to CRP in the Sixth Affiliated Hospital of Sun Yat-sen University from July 2013 to March 2019 were retrospectively analyzed. Inclusion criteria: (1) serious late complications occurred after pelvic radiotherapy, e.g.serious intractable hematochezia (hemoglobin <70 g/L), intractable anal pain (numerical rating scale >7), rectostenosis, perforation, and fistula. (2) imaging examinations including colonoscopy, pelvic MRI and/or chest, abdomen and pelvic CT were performed before surgery to confirm the lesions. Exclusion criteria: (1) preoperative or intraoperative diagnosis of tumor recurrence; (2) only ostomy was performed after laparoscopic exploration; (3) after neoadjuvant radiotherapy for rectal cancer; (4) incomplete medical records. Surgical procedures: (1) Laparoscopic exploration: tumor recurrence was excluded, and the range of radioactive damage in the intestine was determined. Marks were made on the proximal sigmoid colon without grossly obvious edema, thickening or radioactive injuries. (2) Abdominal operation: the right mesentery of sigmoid colon and rectum was opened, inferior mesenteric vein and inferior mesenteric artery were divided and the Toldt gap was expanded inwards and cephalad. The outside of left hemicolon was freed, the gastrocolic ligament was opened, the splenic flexure was fully mobilized, and the rectum was separated from the rear, side and front to the lowest point. Then perineal operation was performed. (3) Perineal operation: the whole layer of rectum wall was cut thoroughly at 1cm below the lesion's lower margin, the space around the rectum was fully separated, the rectum and sigmoid colon was pulled out through the anus and cut off at the site of the grossly normal intestine, the diseased bowel was removed and a coloanal anastomosis was made. (4) A protective stoma was performed. Conditions of operation, complication and symptom relief were summarized. A descriptive statistic method was used to analyze the results.Results:All the 19 patients were female with a median age of 53 (interquartiles, 50, 56) years old, of whom 18 patients had primary cervical cancer. Surgical indications: 9 cases were rectovaginal fistula; 9 cases were intractable anal pain, among whom 7 were complicated with deep rectal ulcer; and 1 case was intractable hematochezia with deep rectal ulcer. Eighteen cases completed laparoscopic Parks procedure, while 1 case was converted to laparotomy. The median operative time was 215 (131, 270) minutes, the median bleeding volume was 50 (50, 100) ml, and the median hospital stay was 12 (11, 20) days. There was no perioperative death. Ten cases had postoperative complications, including 3 cases of serious complications (CD grade IIIb and above) within 30 days after operation, of whom one case developed pelvic infection caused by rectovaginal, rectovesical and rectourethral fistula and acute renal failure (IVa); 2 cases developed orifice prolapse and parastomal hernia (IIIb). Seven cases had anastomosis-related complications, including 4 cases of grade A anastomotic leakage and 3 cases of anastomotic stenosis. Symptoms of CRP in the whole group were significantly relieved or disappeared after one year of the operation. Five cases achieved stoma closure.Conclusions:Laparoscopic Parks procedure for chronic radiation proctopathy is safe and feasible, and can effectively improve symptoms. However, the incidence of anastomotic complications is high, so the surgical indications should be strictly controlled.

Objective:To preliminarily evaluate the feasibility and safety of laparoscopic Parks procedure for chronic radiation proctopathy (CRP).Methods:A descriptive cohort study was carried out. The clinical and follow-up data of 19 patients who received laparoscopic Parks procedure due to CRP in the Sixth Affiliated Hospital of Sun Yat-sen University from July 2013 to March 2019 were retrospectively analyzed. Inclusion criteria: (1) serious late complications occurred after pelvic radiotherapy, e.g.serious intractable hematochezia (hemoglobin <70 g/L), intractable anal pain (numerical rating scale >7), rectostenosis, perforation, and fistula. (2) imaging examinations including colonoscopy, pelvic MRI and/or chest, abdomen and pelvic CT were performed before surgery to confirm the lesions. Exclusion criteria: (1) preoperative or intraoperative diagnosis of tumor recurrence; (2) only ostomy was performed after laparoscopic exploration; (3) after neoadjuvant radiotherapy for rectal cancer; (4) incomplete medical records. Surgical procedures: (1) Laparoscopic exploration: tumor recurrence was excluded, and the range of radioactive damage in the intestine was determined. Marks were made on the proximal sigmoid colon without grossly obvious edema, thickening or radioactive injuries. (2) Abdominal operation: the right mesentery of sigmoid colon and rectum was opened, inferior mesenteric vein and inferior mesenteric artery were divided and the Toldt gap was expanded inwards and cephalad. The outside of left hemicolon was freed, the gastrocolic ligament was opened, the splenic flexure was fully mobilized, and the rectum was separated from the rear, side and front to the lowest point. Then perineal operation was performed. (3) Perineal operation: the whole layer of rectum wall was cut thoroughly at 1cm below the lesion's lower margin, the space around the rectum was fully separated, the rectum and sigmoid colon was pulled out through the anus and cut off at the site of the grossly normal intestine, the diseased bowel was removed and a coloanal anastomosis was made. (4) A protective stoma was performed. Conditions of operation, complication and symptom relief were summarized. A descriptive statistic method was used to analyze the results.Results:All the 19 patients were female with a median age of 53 (interquartiles, 50, 56) years old, of whom 18 patients had primary cervical cancer. Surgical indications: 9 cases were rectovaginal fistula; 9 cases were intractable anal pain, among whom 7 were complicated with deep rectal ulcer; and 1 case was intractable hematochezia with deep rectal ulcer. Eighteen cases completed laparoscopic Parks procedure, while 1 case was converted to laparotomy. The median operative time was 215 (131, 270) minutes, the median bleeding volume was 50 (50, 100) ml, and the median hospital stay was 12 (11, 20) days. There was no perioperative death. Ten cases had postoperative complications, including 3 cases of serious complications (CD grade IIIb and above) within 30 days after operation, of whom one case developed pelvic infection caused by rectovaginal, rectovesical and rectourethral fistula and acute renal failure (IVa); 2 cases developed orifice prolapse and parastomal hernia (IIIb). Seven cases had anastomosis-related complications, including 4 cases of grade A anastomotic leakage and 3 cases of anastomotic stenosis. Symptoms of CRP in the whole group were significantly relieved or disappeared after one year of the operation. Five cases achieved stoma closure.Conclusions:Laparoscopic Parks procedure for chronic radiation proctopathy is safe and feasible, and can effectively improve symptoms. However, the incidence of anastomotic complications is high, so the surgical indications should be strictly controlled.