[Cross-sectional study of low anterior resection syndrome in patients who have survived more than 5 years after sphincter-preserving surgery for rectal cancer].

Objective: In this study, we aimed to investigate the prevalence of low anterior resection syndrome (LARS) in patients who had survived for more than 5 years after sphincter-preserving surgery for rectal cancer and to analyze its relationship with postoperative time. Methods: This was a single-center, retrospective, cross-sectional study. The study cohort comprised patients who had survived for at least 5 years (60 months) after undergoing sphincter- preserving radical resection of pathologically diagnosed rectal adenocarcinoma within 15 cm of the anal verge in the Department of Gastrointestinal Surgery, Peking University People's Hospital from January 2005 to May 2016. Patients who had undergone local resection, had permanent stomas, recurrent intestinal infection, local recurrence, history of previous anorectal surgery, or long- term preoperative defecation disorders were excluded. A LARS questionnaire was administered by telephone interview, points being allocated for incontinence for flatus (0-7 points), incontinence for liquid stools (0-3 points), frequency of bowel movements (0-5 points), clustering of stools (0-11 points), and urgency (0-16 points). The patients were allocated to three groups based on these scores: no LARS (0-20 points), minor LARS (21-29 points), and major LARS (30-42 points). The prevalence of LARS and major LARS in patients who had survived more than 5 years after surgery, correlation between postoperative time and LARS score, and whether postoperative time was a risk factor for major LARS and LARS symptoms were analyzed. Results: The median follow-up time of the 160 patients who completed the telephone interview was 97 (60-193) months; 81 (50.6%) of them had LARS, comprising 34 (21.3%) with minor LARS and 47 (29.4%) with major LARS. Spearman correlation analysis showed no significant correlation between LARS score and postoperative time (correlation coefficient α=-0.016, P=0.832). Multivariate analysis identified anastomotic height (RR=0.850, P=0.022) and radiotherapy (RR=5.760, P<0.001) as independent risk factors for major LARS; whereas the postoperative time was not a significant risk factor (RR=1.003, P=0.598). The postoperative time was also not associated with LARS score rank and frequency of bowel movements, clustering, or urgency (P>0.05). However, the rates of incontinence for flatus (3/31, P=0.003) and incontinence for liquid stools (8/31, P=0.005) were lower in patients who had survived more than 10 years after surgery. Conclusions: Patients with rectal cancer who have survived more than 5 years after sphincter-preserving surgery still have a high prevalence of LARS. We found no evidence of major LARS symptoms resolving over time.

[Correlation between pelvic relapses of rectal cancer after radical and R0 resection: A regression model-based analysis].

Objective: To propose a new staging system for presacral recurrence of rectal cancer and explore the factors influencing radical resection of such recurrences based on this staging system. Methods: In this retrospective observational study, clinical data of 51 patients with presacral recurrence of rectal cancer who had undergone surgical treatment in the Department of Gastrointestinal Surgery, Peking University People's Hospital between January 2008 and September 2022 were collected. Inclusion criteria were as follows: (1) primary rectal cancer without distant metastasis that had been radically resected; (2) pre-sacral recurrence of rectal cancer confirmed by multi-disciplinary team assessment based on CT, MRI, positron emission tomography, physical examination, surgical exploration, and pathological examination of biopsy tissue in some cases; and (3) complete inpatient, outpatient and follow-up data. The patients were allocated to radical resection and non-radical resection groups according to postoperative pathological findings. The study included: (1) classification of pre-sacral recurrence of rectal cancer according to its anatomical characteristics as follows: Type I: no involvement of the sacrum; Type II: involvement of the low sacrum, but no other sites; Type III: involvement of the high sacrum, but no other sites; and Type IV: involvement of the sacrum and other sites. (2) Assessment of postoperative presacral recurrence, overall survival from surgery to recurrence, and duration of disease-free survival. (3) Analysis of factors affecting radical resection of pre-sacral recurrence of rectal cancer. Non-normally distributed measures are expressed as median (range). The Mann-Whitney U test was used for comparison between groups. Results: The median follow-up was 25 (2-96) months with a 100% follow-up rate. The rate of metachronic distant metastasis was significantly lower in the radical resection than in the non-radical resection group (24.1% [7/29] vs. 54.5% [12/22], χ2=8.333, P=0.026). Postoperative disease-free survival was longer in the radical resection group (32.7 months [3.0-63.0] vs. 16.1 [1.0-41.0], Z=8.907, P=0.005). Overall survival was longer in the radical resection group (39.2 [3.0-66.0] months vs. 28.1 [1.0-52.0] months, Z=1.042, P=0.354). According to univariate analysis, age, sex, distance between the tumor and anal verge, primary tumor pT stage, and primary tumor grading were not associated with achieving R0 resection of presacral recurrences of rectal cancer (all P>0.05), whereas primary tumor pN stage, anatomic staging of presacral recurrence, and procedure for managing presacral recurrence were associated with rate of R0 resection (all P<0.05). According to multifactorial analysis, the pathological stage of the primary tumor pN1-2 (OR=3.506, 95% CI: 1.089-11.291, P=0.035), type of procedure (transabdominal resection: OR=29.250, 95% CI: 2.789 - 306.811, P=0.005; combined abdominal perineal resection: OR=26.000, 95% CI: 2.219-304.702, P=0.009), and anatomical stage of presacral recurrence (Type III: OR=16.000, 95% CI: 1.542 - 166.305, P = 0.020; type IV: OR= 36.667, 95% CI: 3.261 - 412.258, P = 0.004) were all independent risk factors for achieving radical resection of anterior sacral recurrence after rectal cancer surgery. Conclusion: Stage of presacral recurrences of rectal cancer is an independent predictor of achieving R0 resection. It is possible to predict whether radical resection can be achieved on the basis of the patient's medical history.

[Anastomotic vessels between superior mesenteric artery and inferior mesenteric artery: controversies and advances].

The anastomotic vessels between the superior mesenteric artery and the inferior mesenteric artery are vital to maintain the blood supply of the anastomosis and residual colon after colectomy. However, current studies of anastomotic vessels are facing four major obstacles: confusing nomenclature, large variability in data, diversification of research methods and incomplete information records. The existence of marginal artery has been widely proved, and its significance for blood supply is well recognized by relevant studies. In contrast, the Riolan's arch, whose connotations constantly changed over history, can not refer to a specific structure accurately. Researchers should abolish the controversial names such as Riolan's arch, select appropriate research methods and record the anastomotic vessels in detail, so as to improve the comparability between different results. The study of anastomotic vessels can help us to identify potential vascular disease, select the appropriate surgical approach, and provide appropriate treatment of the vessels in the operating area, so as to provide a theoretical foundation and practical basis for fine surgical maneuvers.

[Influence of different sphincter-preserving surgeries on postoperative defecation function].

Advances in surgical techniques and treatment concept have allowed more patients with low rectal cancer to preserve sphincter without sacrificing survival benefit. However, postoperative dysfunctions such as fecal incontinence, frequency, urgency, and clustering often occur in patients with low rectal cancer. The main surgical procedures for low rectal cancer include low anterior rectum resection (LAR), intersphincteric resection (ISR), coloanal anastomosis (Parks) and so on. The incidence of major LARS after LAR is up to 84.6%. The postoperative function of ISR is even worse than LAR. Moreover, the greater the extent of resection ISR surgery, the worse the postoperative function. There are few studies on the function of Parks procedure. Current evidence suggests that the short-term function of Parks procedure is inferior to LAR, but function can gradually recovered over time. Colorectal surgeons have attempted to improve postoperative defecation by modifying bowel reconstructions. Current evidence suggests that J pouch or end-to-side anastomosis during LAR does not reduce the incidence of defecation disorders. Pouch reconstruction during ISR cannot reduce the incidence of severe LARS either. In general, the protection of postoperative defecation function in patients with low rectal cancer still has a long way to go.

[Research progress of colorectal surgery in 2021 and future prospects].

In recent years, with the wide application of immune score and liquid biopsy to guide the accurate diagnosis and precise treatment of colorectal cancer, colorectal surgery develops more rationally and scientifically. The strategy of organ function protection in colorectal surgery gradually attracts more and more attention. The continuous development of comprehensive treatments, such as targeted therapy and immunotherapy, provides more choices for colorectal cancer patients. Several significant progress in surgical strategies for benign colorectal diseases challenges the traditional concepts as well. The advances in medical science and the innovation of concepts and ideas set high new standards for the development of colorectal surgery in China. Efforts are required to improve the standardization of diagnosis and treatment of colorectal disease. There is still a long way to go to explore patient-centered new technologies, new concepts and new fields of accurate diagnosis and precise treatment in colorectal surgery.

[Research progress of sexual dysfunction following rectal cancer surgery].

Sexual dysfunction with the incidence of 5%-90% is a common postoperative complication of rectal cancer and the ratio of men and women is similar. Sexual function is innervated by the abdominal-pelvic autonomic nerve. Different sexual dysfunctions can be caused by different parts and degrees of injury in autonomic nerve during operations of rectal cancer. With the development of pelvic autonomic nerves preservation in rectal cancer radical resection, postoperative sexual function can be protected. There may be many factors increasing the incidence of postoperative sexual dysfunction in rectal cancer, such as postoperative psychological factors, stoma, abdominal-perineal resection and radiotherapy. The effects of laparoscopic surgery, robotic surgery, transanal total mesorectal excision and lateral lymph node dissection on postoperative sexual function remain controversial. Based on the multidisciplinary cooperation model, attention should be paid to psychological intervention of patients and their partners. In clinical practice, for male using phosphodiesterase-5 inhibitors, vacuum erectile devices, injection of vasodilators through the penis or urethra, and for female local application of estrogen and lubricants in the vagina are effective treatment for postoperative sexual dysfunction of rectal cancer. In addition, stem cell therapy has a promising prospect for sexual dysfunction.

[Research progress of single-incision laparoscopic radical gastrectomy].

Gastric cancer is one of the most common malignant diseases in the world, which has a high incidence in our country and threatens people's health seriously. Laparoscopic radical gastrectomy is one of the main methods of surgical treatment for gastric cancer, whose clinical application has a history of near 30 years. With the in-depth understanding of minimally invasive surgery and the improvement of patients' cosmetic demand, single-incision laparoscopic surgery has emerged. Since the first report of single-incision laparoscopic radical gastrectomy in 2010, its safety has been preliminarily confirmed. While this result still needs to be further verified by more prospective randomized controlled studies. Compared with traditional laparoscopic radical gastrectomy, single-incision laparoscopic radical gastrectomy has the advantages of less trauma, less postoperative pain and faster postoperative recovery. So it has been favored by surgeons. However, the steeper learning curve and difficult operation of single-incision laparoscopic radical gastrectomy limit its promotion in clinical applications. At present, there are still controversies and confusions in the single-incision laparoscopic radical gastrectomy. This article elucidates the advances and existing problems of single-incision laparoscopic radical gastrectomy.

[Fat1 inhibits cell proliferation via ERK signaling pathway in esophageal squamous cell carcinoma].

Objective: To clarify the mechanism of Fat1 on the proliferation of esophageal squamous cell carcinoma (ESCC). Methods: KYSE450 cells were transfected with Plko.1-puro-GFP-shRNA-Fat1 plasmid and real time polymerase chain reaction (PCR) was used to verify the efficiency of Fat1 knockdown. The effects of Fat1 and extracellular regulated protein kinase (ERK) pathway inhibitor U0126 on the proliferation of ESCC cells were detected by methyl thiazolyl tetrazolium (MTT). Colony formation assay was used to detect the colony formation ability. Cell cycle was detected by live cell imaging. Western blot was used to observe the level of target protein. Mouse xenograft assay was applied to detect the effect of Fat1 knockdown on KYSE450 cell tumor growth. Immunohistochemistry was used to detect the expressions of related proteins in tumor sections. Results: The efficiency of Fat1 knockdown was (77.1±6.9)% in Fat1 sh1 group and (77.7±7.1)% in Fat1sh2 group. Compared with the control group, the cell proliferation and the expression of p-ERK1/2 were significantly increased in Fat1 sh1 and Fat1sh2 group (P<0.05). After U0126 treatment, the effect of Fat1 knockdown on the proliferation of KYSE450 cells disappeared, and the expression of p-ERK1/2 in KYSE450 cells decreased to a level similar to that in the control group. The number of cell clones in the control group was (72±8), lower than (155±28) and (193±9) in the Fat1sh1 and Fat1sh2 groups, respectively (P<0.05). In KYSE450 cell, division time was shortened from 1 622±32 min in control group to 1 408±29 min in Fat1 sh1 group, the difference was statistically significant (P<0.05). Compared with the control group, the tumor volume of Fat1 knockdown group increased significantly. The tumor weight of control group and Fat1 knockdown group were (0.224±0.028) g and (1.532±0.196) g, respectively, at 4 weeks after inoculation, and the difference was statistically significant (P<0.05). Conclusion: Fat1 inhibits cell proliferation via ERK signaling in ESCC.

[Pros and cons of perioperative therapy in the protection of organ function in rectal cancer].

The goal of rectal cancer treatment should be to better protect organ function and improve patients' quality of life on the basis of ensuring radical resection. The current evidence has proved the superiority of perioperative chemoradiotherapy in reducing local recurrence and improving long-term survival. From the perspective of organ function protection, however, perioperative chemoradiotherapy has both disadvantages and advantages. Despite the great help in improving long-term outcomes, adverse reactions of chemoradiotherapy can aggravate defecation, urination and sexual dysfunction. Also, for patients with significant or complete remission, if the treatment strategy of local resection or close follow-up is selected, organ function can be preserved to the greatest extent. The key to the choice of treatment is to evaluate preoperatively whether pathological complete response is achieved. It should be kept in mind that preserving organ itself is not the same as protecting organ function. For patients who need perioperative chemoradiation, the optimal treatment methods should be chosen based on the patient's condition. Surgeons should fully evaluate organ function before operation, select the appropriate treatment strategy, pay special attention to the protection of important organs and nerves during surgeries, and carry out close postoperative follow-up and organ function rehabilitation as soon as possible, so as to reduce the incidence of dysfunction and the impact on the quality of life.

[Investigation on the status quo of diagnosis and treatment related to the protection of defecation function in sphincter-preserving resections for rectal cancer: a cross-sectional study of Chinese colorectal surgeons].

Objective: To understand the current status of diagnosis and treatment regarding the protection of defecation function in Chinese surgeons performing sphincter-preserving resections (SPR) for rectal cancer in order to discover the problems existing in the function protection during SPR and provide support and reference for the standardized clinical management of rectal cancer. Methods: A cross-sectional survey was performed. Colorectal surgeons who obtained the medical qualifications and volunteered to participate in this study were included, and respondents with incomplete information were excluded. From October 18 to 22, 2020, randomized sampling was conducted among Chinese colorectal surgeons from Chinese Association of Colorectal Surgeons, Chinese Colorectal Cancer Committee, Chinese Sexology Association Anal functional Surgery Committee and National Health Commission Capacity Building and Continuing Education Committee. The questionnaire included basic information of the respondents, assessment of defecation function before SPR, intraoperative details, postoperative follow-up, evaluation and intervention of patients with low anterior resection syndrome (LARS). Observation indicator: results of the questionnaire survey. Result: A total of 231 questionnaires were collected, and 230 were effective, with an effective rate of 99.6%. Among these participants, 217 (94.3%) were males; 107 (46.5%) had medical doctor degrees; 129 (56.1%) were national commission members in colorectal surgery; 137 (59.6%) performed more than 50 SPR operations per year; 211 (91.7%) assessed defection function by auxiliary examinations before SPR. Rigid sigmoidoscopy (n=116, 55.0%) and anorectal manometer (n=81, 38.4%) were the most commonly used method. Among the 230 respondents, 64.8% (n=149) of surgeons used 2D laparoscopy for SPR surgery most commonly, and 51.3% (n=118) of surgeons performed direct colorectal anastomosis for reconstruction, and 98.3% (n=226) used staplers during anastomosis. All the surgeons indicated that they would follow up patients after SPR, and outpatient clinic was the most common method (84.4%, 184/230). When LARS occurred, 50.0% (115/230) of surgeons chose defecation function scale and 78.7% (181/230) actively provided guidance and intervention for patients. Conclusions: Chinese colorectal surgeons still have shortcomings in the protection of defecation function during SPR for rectal cancer. They do not make enough preoperative functional evaluation and postoperative functional recovery estimate for patients. The knowledge and use of defecation function scales and interventions on LARS are expected to be standardized.

[Research progress of different bowel reconstructions for postoperative functional protection during low anterior resections of rectal cancer].

Straight coloanal anastomosis (SCA), colonic J-pouch anastomosis (CJP), transverse coloplasty pouch anastomosis (TCP), and side-to-end anastomosis (SEA) are the most commonly used procedures of bowel reconstructions in the low anterior resections (LAR) of rectal cancer. Different bowel reconstruction procedures greatly affect postoperative bowel function, urinary function and sexual function. SCA is the most traditional procedure. CJP has been studied extensively and well-developed reconstruction method; however, recent studies have shown that CJP has the highest morbidity of complications, so the clinical application of CJP is limited. SEA is not inferior to CJP and SCA in the short-term and long-term defecation function, urination function, and sexual function, with reliable operational safety, so it is expected to become an alternative to SCA and CJP. The research on TCP is lacking, but there are some related clinical trials currently underway, and the results are worth expecting. The improvement and innovation of bowel reconstructions provide a bright prospect for better functional prognosis in patients with rectal cancer.

[Safety and efficacy of adjuvant chemotherapy with oxaliplatin and S-1 for patients with locally advanced gastric cancer after D2 lymph nodes dissection].

Objective: To investigate the safety and efficacy of oxaliplatin combined with S-1 (SOX) as adjuvant chemotherapy after D2 radical gastrectomy for locally advanced gastric cancer. Methods: A descriptive case series study was applied. Case inclusion criteria: (1) locally advanced gastric cancer confirmed by endoscopic biopsy or surgical specimen pathology as gastric adenocarcinoma; (2) receiving D2 radical gastric resection followed by SOX regimen adjuvant chemotherapy. Case exclusion criteria: (1) postoperative pathological TNM stage I or IV; (2) acute complications and emergency surgeries; (3) receiving neoadjuvant therapy; (4) concurrent malignancies and complications compromising patients' treatment or survival; (5) without receiving adjuvant SOX chemotherapy. A total of 94 patients with stage II-III gastric cancer who underwent D2 radical gastrectomy and postoperative adjuvant SOX chemotherapy at department of Gastrointestinal Surgery, Peking University People's Hospital from January 2014 to December 2019 were retrospectively enrolled. Chemotherapy-related adverse events, overall survival (OS) and progression-free survival (PFS) were analyzed. Kaplan-Meier survival analysis was performed and log rank test was used to analyze the difference between groups. P<0.2 or clinically significant indicators in univariate analysis were included in Cox regression model for multivariate survival analysis. Results: Among these 94 patients, there were 65 males and 29 females with an average age of (58.2±12.1) years; 33 patients with hypertension, diabetes mellitus, or cardiovascular and cerebrovascular diseases, 11 patients with family history of gastrointestinal tumors; 59 patients with tumors locating in the antrum or pylorus, 16 patients in the gastric body, 19 patients in the gastric fundus or cardia; 29 patients underwent total gastrectomy, 5 patients underwent proximal subtotal gastrectomy, and 60 patients underwent distal subtotal gastrectomy. In this study, 73 patients (77.7%) completed at least 5 cycles of adjuvant SOX regimen chemotherapy. Grade 3-4 adverse reactions included thrombocytopenia (23.4%, 22/94), nausea and vomiting (18.1%, 17/94) and peripheral neurotoxicity (6.4%, 6/94). Eighty-nine patients (94.7%) completed follow-up with a median follow-up time of 32 months. The 3-year and 5-year OS rates were 89.8% and 83.7%, respectively, and the 3-year and 5-year PFS rates were 81.4% and 78.1%, respectively. Taking 5 chemotherapy cycles as the cut-off point, the 3-year OS rate and 3-year PFS rate were 72.2% and 53.9% in the adjuvant chemotherapy < 5 cycles group, and 93.7% and 87.1% in the adjuvant chemotherapy ≥5 cycles group, respectively; the differences were statistically significant (P=0.029, P=0.006). Univariate analysis showed that the adjuvant chemotherapy < 5 cycles group was associated with worse 3-year OS (P=0.029). Multivariate analysis showed that insufficient chemotherapy cycle (HR=9.419, 95% CI: 2.330-38.007, P=0.002) was an independent risk factor for 3-year OS. Meanwhile, univariate analysis showed that the adjuvant chemotherapy <5 cycles (P=0.006), preoperative CEA > 4.70 µg/L (P=0.035) and adjacent organ resection (P=0.024) were associated with worse 3-year PFS. Multivariate analysis showed that adjuvant chemotherapy <5 cycles (HR=10.493, 95% CI: 2.466-44.655, P=0.001) and adjacent organ resection (HR=127.518, 95% CI: 8.885-1 830.136, P<0.001) were independent risk factors for 3-year PFS. Conclusions: Oxaliplatin combined with S-1 as an adjuvant chemotherapy regimen for locally advanced gastric cancer has high efficacy and low incidence of adverse reactions. At least 5 cycles of SOX regimen adjuvant chemotherapy can significantly improve prognosis of patients with stage II-III gastric cancer.

[Guidance of magnetic resonance imaging for target area delineation of postoperative presacral recurrence of rectal cancer].

Objective: Presacral recurrence of rectal cancer have altered the adjacent structures of original pelvic organs due to the previous radical surgery of rectal cancer, and the boundary between recurrent tumor tissues and pelvic internal structures is not clear. Conventional CT examination has poor soft tissue resolution, which makes it difficult to accurately delineate the target area of radiotherapy. This study aimed to explore the guiding role of magnetic resonance imaging (MRI) in delineating the target area of presacral recurrence after radical resection of rectal cancer. Methods: A descriptive case series research method was adopted. From May 2014 to May 2019, the clinical data of 30 patients with presacral recurrence after radical resection of rectal cancer were collected, who were admitted to Peking University People's Hospital, confirmed by pathology or discussed by multidisciplinary team (MDT), with complete MRI, CT and case information. According to the gross tumor volume (GTV) with presacral recurrence outlined in CT and MRI images, including presacral recurrent lesions (GTVT) and metastatic lymph nodes (GTVN), the GTV volume was calculated, and the tumor boundary and diameter were measured. The differences between MRI and CT were compared. Results: The volume of GTVT-CT was larger than that of GTVT-MR in all the 30 patients. The median volume of GTVT-CT was 67.86 (range 5.12-234.10) cm(3), which was significantly larger than 43.02 (range 3.42-142.50) cm(3) of GTVT-MR with statistically significant difference (Z=-4.288, P<0.001). The mean volume of GTVN outlined by CT and MRI was (0.43±0.11) cm(3) and (0.40±0.10) cm(3) respectively without statistically significant difference (t=1.550, P=0.132). The mean values of boundary and radial line of the presacral lesions on CT images were all longer than those on MRI images. The vertical diameter of GTVT on CT and MRI images was (6.66±2.92) cm and (5.17±2.40) cm (t=5.466, P<0.001); the anterior boundary was (3.24±2.51) cm and (2.69±2.48) cm (t=4.685, P<0.001); the anteroposterior diameter was (4.92±2.02) cm and (4.04±1.57) cm (t=6.210, P<0.001); the left boundary was (3.05±1.00) cm and (2.64±0.78) cm (t=2.561, P=0.016); the right boundary was 2.66 (0.00-4.23) cm and 1.82 (-1.10-3.59) cm (Z=-3.950, P<0.001); the transverse diameter was (5.01±1.78) cm and (3.82±1.29) cm (t=4.648, P<0.001), respectively, whose differences were all statistically significant. MRI was superior to CT in judging the involvement of anterior organs, such as intestine, prostate, bladder and the posterior sacrum. Fifteen patients received radiotherapy according to the target area guided by MRI and 10 patients obtained clinical symptom relief. Conclusion: Compared with CT, the GTV of postoperative presacral recurrence of rectal cancer outlined in MRI images is smaller, and MRI can determine the boundary between tumor and surrounding normal tissues more precisely, so it can show the invasion range of tumor more accurately and guide the accurate implementation of radiotherapy.

[Diagnosis and treatment of pneumatosis cystoides intestinalis].

Pneumatosis cystoides intestinalis (PCI) is a rare disease, which is characterized by the accumulation of gas cysts located in the submucosa or subserosa of the gastrointestinal tract. It can occur in the whole or part of the gastrointestinal tract from the esophagus to the rectum, but clinically the main involved sites are the colon and small intestine. PCI can also appear in other sites such as mesentery, the greater omentum and the hepatogastric ligament. In recent years, with the renewal of imaging method, the detection rate of PCI has been on the rise. Most patients with PCI have no obvious symptoms or only non-specific symptoms of the digestive tract like abdominal distension, abdominal pain, diarrhea, hematochezia, etc. The atypical clinical symptoms of PCI can easily lead to missed diagnosis or misdiagnosis. A small amount of patients would have complications like peritonitis and even perforation of the digestive tract. The therapeutic principle for these patients is different from that for patients with acute abdomen. The prognosis of PCI depends on its severity and comorbidities. In this article, a literature review would be conducted on the epidemiological characteristics, etiology and pathogenesis, clinical manifestations, diagnosis and treatment of PCI, which might help clinical doctors with diagnosis and treatment of the disease.

[Evidence-based standardized diagnosis and treatment of small gastrointestinal stromal tumors].

The actual incidence of small gastrointestinal stromal tumors (GIST) increases gradually. Although the biological behavior of most of small GIST is benign or indolent, a few small GIST can develope to recurrence and metastasis with biological invasive behavior. Identification of biological behavior and malignant potential is the cornerstone of treatment. For non-gastric small GIST, surgery is always the treatment of choice. Regarding gastric small GIST, close follow-up is acceptable for patients without risk factors detected by endoscopic ultrasonography. Surgery should be suggested for those with high risks, or significant growth of tumor during follow-up. Complete resection with function preservation is the principle of surgery. Besides, individualized treatment should also be taken into consideration.

[Surgical treatment of presacral recurrent rectal cancer].

Presacral recurrent rectal cancer (PRRC) which involves the presacral fascia or/and sacral bone is one of the classification of locally recurrent rectal cancer. Presacral fascia or/and sacral bone involvement and posterior fixation make treatment difficult. In recent years, there are many researches on the diagnosis, surgical treatment and surgical methods of PRRC. The major therapeutic principle of PRRC is to perform radical resection with combined therapy under the evaluation of the multidisciplinary team (MDT). Among the surgical methods, abdominal resection or abdominoperineal resection, sacrectomy and abdominosacral resection are the common surgical methods for the treatment of PRRC. Recent articles revealed that limited sacrectomy could also result in good efficacy, provided strict indications for this procedure. With the development of minimally invasive technology, the application of laparoscopic technology in PRRC has been increasingly emphasized. In summary, the surgical principle of PRRC has shifted from solely pursuring radical resection to obtaining good efficacy as well as reduced morbidity with individualized management. In this article, the research progress of surgical methods of presacral recurrent rectal cancer in recent years are reviewed in order to provide reference to clinical diagnosis and treatment.

[Clinicopathological features and prognosis in patients with presacral recurrent rectal cancer].

Objective: To investigate the clinicopathological features and prognostic factors in patients with presacral recurrent rectal cancer (PRRC). Methods: PRRC was defined as recurrence of rectal cancer after radical surgery involving posteriorly the presacral soft tissue, the sacrum/coccyx, and/or sacral nerve root. The diagnosis is confirmed with clinical symptoms (pain of pelvis/back/lower limb, bloody stools, increased frequency of defecation, and abnormal secretions), physical examination of perineal or pelvic masses, radiological findings, colonoscopy with histopathological biopsy, and the evaluation by multi-disciplinary team (MDT). Inclusion criteria: (1) primary rectal cancer undergoing radical surgery without distant metastasis; (2) PRRC was diagnosed; (3) complete inpatient, outpatient and follow-up data. According to the above criteria, clinical data of 72 patients with PRRC in Peking University People's Hospital from January 2008 to December 2017 were retrospectively analyzed. The clinicopathological features and follow-up data were summarized. Cox proportional hazard models was used to analyze the prognostic factors of PRRC. Results: Among 72 patients, 45 were male and 27 were female with a male-to-female ratio of 1.7:1.0. The median age at recurrence was 58 (34 to 83) years and the median interval from surgery to recurrence was 2.0 (0.2 to 17.0) years. The main symptom was pain in 48.6% (35/72) of patients. In addition, gastrointestinal symptoms were found in 25.0% (18/72) of patients. The presacral recurrent sites were presacral fascia in 36 (50.0%) patients, lower sacrum (S3~S5 or coccyx) in 25 (34.7%) patients, and higher sacrum (S1~S2) in 11 (15.3%) patients. Forty-seven (65.3%) patients underwent radical surgery (abdominal resection, abdominoperineal resection, sacrectomy, abdominosacral resection), 12 (16.7%) underwent non-radical surgery (colostomy, cytoreductive surgery), and 13 (18.1%) did not undergo any surgery but only receive palliative chemoradiotherapy and nutritional support treatment. Thirty-three (45.8%) patients received radiotherapy and/or chemotherapy (oxaliplatin, 5-fluorouracil, capecitabine, irinotecan, etc.). All the patients received follow-up, and the median follow-up time was 19 (2 to 72) months. The median overall survival time was 14 (1 to 65) months. The 1- and 3-year overall survival rates were 67.1% and 32.0%, respectively. Univariate analysis showed that age at recurrence (P=0.031) and radical resection (P<0.001) were associated with prognosis. Multivariate analysis demonstrated that radical resection was independent factor of good prognosis (RR=0.140, 95%CI: 0.061-0.322, P<0.001). Conclusions: Patients tend to develop presacral recurrent rectal cancer within 2 years after primary surgery. The main symptom is pain. Patients undergoing radical resection have a relatively good prognosis.

[Comparison of clinical efficacy among different surgical methods for presacral recurrent rectal cancer].

Objective: To investigate the efficacy and prognosis of three surgical methods for presacral recurrent rectal cancer (PRRC). Methods: A retrospective cohort study was carried out. Case inclusion criteria: (1) primary rectal cancer without distant metastasis and undergoing radical surgery; (2) patients undergoing radical surgery after the diagnosis of PRRC; (3) complete inpatient, outpatient and follow-up data. Clinical data of 47 patients meeting the above criteria who underwent operation at the Department of Gastrointestinal Surgery, The Peking University People's Hospital from January 2008 to December 2017 were reviewed and analyzed retrospectively. Of the 47 patients, 31 were male and 16 were female; the mean age was 57 years old; 9 (19.1%) were low differentiation or signet ring cell carcinoma, 38 (80.9%) were medium differentiation; 19 (40.4%) received neoadjuvant therapy. According to operative procedure, 22 patients were in the abdominal/abdominoperineal resection group, 15 in the sacrectomy group and 10 in the abdominosacral resection group. The operative data, postoperative data and prognosis were compared among the three groups. Survival curve was conducted using the Kaplan-Meier method, and log-rank test was used to compare survival difference among three groups. Results: There were no significant differences in baseline data among three groups (all P>0.05). All the 47 patients completed the radical resection successfully. The mean operation time was (4.7±2.1) hours, the median intraoperative blood loss was 600 ml, and the median postoperative hospitalization time was 17 days. Fifteen cases (31.9%) had perioperative complications, of which 3 cases were grade III-IV. There was no perioperative death. The mean operative time was (7.4±1.6) hours in the abdominosacral resection group, (4.9±1.6) hours in the abdominal/abdominoperineal resection group, and (3.0±1.1) hours in the sacroectomy group, with a significant difference (F=25.071, P<0.001). There were no significant differences in intraoperative blood loss, postoperative hospitalization days and perioperative complications among the three groups (all P>0.05). The median follow-up period of all the patients was 24 months, 12 cases (25.5%) developed postoperative dysfunction. The incidence of postoperative dysfunction in the abdominosacral resection group was 5/10, which was higher than 4/15 in the sacrectomy group and 3/22 (13.6%) in the abdominoperineal resection group with statistically significant difference (χ(2)=9.307, P=0.010). The 1-year and 3-year overall survival rates were 86.1% and 40.2% respectively. The 1-year overall survival rates were 86.0%, 86.7% and 83.3%, and the 3-year overall survival rates were 33.2%, 40.0% and 62.5% in the abdominal/abdominoperineal resection group, sacrectomy group and abdominosacral resection group, respectively, whose difference was not statistically significant (χ(2)=0.222, P=0.895). Conclusions: Abdominal/abdominoperineal resection, sacrectomy and abdominosacral resection are all effective for PRRC. Intraoperative function protection should be concerned for patients undergoing abdominosacral resection.

[Controversy and consideration of high and low ligation of inferior mesenteric artery in radical resection of rectal cancer].

Radical resection is one of the most important treatment for rectal cancer, which requires not only removal of adequate bowel and mesorectum around the tumor, but also thorough lymphadenectomy. Besides, postoperative complications are surgeons' concerns as well. According to different ways to manage inferior mesenteric artery, procedures could be divided into two groups: inferior mesenteric artery (IMA) high ligation and low ligation, which lead to various outcomes of the extent of lymph nodes dissection, survival, preservation of intestinal blood supply, incidence of anastomotic leakage, and postoperative functions including defecation function, urinary function and sexual function. Author believes that for those patients with clinical stage T1, low ligation and D2 lymph nodes dissection could be considered. However, for patients with locally advanced carcinomas (clinical stage T2+or N+), especially suspicious metastasis of lymph nodes around IMA root, high ligation and D3 lymph node dissection is suggested to ensure en bloc resection. As for those patients with high risks for compromised intestinal blood supply, preservation of left colic artery plus D3 lymph nodes dissection might be a feasible way. Intraoperative indocyanine green fluorescent imaging might play a role in quality control of lymphadenectomy.