Proposal for a new classification of anorectal abscesses based on clinical characteristics and postoperative recurrence

BACKGROUND Current surgical procedures for anorectal abscesses,including incision and drainage alone or combined concurrent fistulotomy,remain controversial primarily due to the unpredictability of postoperative recurrence or the progression to anal fistula.AIM To evaluate factors that predict postoperative recurrence of anorectal abscesses and propose a new classification to guide surgical procedures.METHODS In this retrospective study,525 patients with anorectal abscesses treated by incision and drainage alone,at a tertiary general hospital from August 2012 to July 2022,were included.A new classification for anorectal abscesses based on their propensity to develop into fistulas,considering 18 other potential risk factors,was established.These factors,from electronic medical records,were screened for significance using theχ^(2)test and subsequently analyzed with multivariate logistic regression to evaluate their relationship with postoperative recurrence of anorectal abscesses.RESULTSOne year post-follow-up,the overall recurrence rate was 39%:81.0%and 23.5%for fistula-prone and non-fistulaproneabscesses,respectively.Univariateχ^(2)analysis showed significant differences in recurrence rates based onanatomical classifications and pus culture results(P<0.05).Fistula-prone abscess,≥7 days between symptomonset and surgery,chronic diarrhea,preoperative antibiotic use,and local anesthesia were risk factors for recurrence,while diabetes mellitus was protective(P<0.05).Moreover,fistula-prone abscess[odds ratio(OR)=7.651,95%CI:4.049–14.458,P<0.001],≥7 days from symptom onset to surgery(OR=2.137,95%CI:1.090–4.190,P=0.027),chronic diarrhea(OR=2.508,95%CI:1.216–5.173,P=0.013),and local anesthesia(OR=2.308,95%CI:1.313–4.059,P=0.004)were independent risk factors for postoperative anorectal abscess recurrence using multivariatelogistic regression.Body mass index≥28(OR=2.935,95%CI:1.203–7.165,P=0.018)was an independentrisk factor for postoperative recurrence of non-fistula-prone abscess.CONCLUSIONThe choice of surgical procedure for treating anorectal abscesses should follow this new classification.Prompt andthorough incision and drainage can significantly reduce postoperative recurrence.

Differing coping mechanisms, stress level and anorectal physiology in patients with functional constipation

AIM: To investigate coping mechanisms, constipation symptoms and anorectal physiology in 80 constipated subjects and 18 controls.METHODS: Constipation was diagnosed by Rome Ⅱ criteria.Coping ability and anxiety/depression were assessed by validated questionnaires. Transit time and balloon distension test were performed.RESULTS: 34.5% patients were classified as slow transit type of constipation. The total colonic transit time (56 h vs 10 h, P＜0.0001) and rectal sensation including urge sensation (79 mL vs 63 mL, P = 0.019) and maximum tolerable volume (110 mL vs95 mL, P = 0.03) differed in patients and controls. Constipated subjects had significantly higher anxiety and depression scores and lower SF-36 scores in all categories. They also demonstrated higher scores of'monitoring' coping strategy (14+6 vs9+3, P = 0.001),which correlated with the rectal distension sensation (P = 0.005), urge sensation (P=0.002), and maximum tolerable volume (P = 0.035). The less use of blunting strategy predicted slow transit constipation in both univariate (P = 0.01) and multivariate analysis (P = 0.03).CONCLUSION: Defective or ineffective use of coping strategies may be an important etiology in functional constipation and subsequently reflected in abnormal anorectal physiology.

Endoscopic submucosal dissection as excisional biopsy for anorectal malignant melanoma:A case report

BACKGROUND Anorectal malignant melanoma(AMM)is a rare disorder with an extremely poor prognosis.Although there is currently no consensus on the treatment methods for AMM,surgical procedures have been the most common treatment methods used until now.We recently encountered a case of AMM that we diagnosed using endoscopic submucosal dissection(ESD).To our knowledge,this is the first case of ESD for AMM,suggesting that ESD can potentially be a diagnostic and treatment method for AMM.CASE S UMA/MARY A 77-year-old woman visited our hospital with a chief complaint of anal bleeding and a palpable rectal mass.Colonoscopy revealed a 20-mm protruded lesion in the lower rectum.After obtaining biopsy specimens from the lesion,although a malignant rectal tumor was suspected,a definitive diagnosis was not made.Endoscopic ultrasonography revealed tumor invasion into the submucosal layer but not the muscular layer.Therefore,we performed an excisional biopsy using ESD.Immunohistochemical examination of the ESD-resected specimen revealed tumor cells positive for Human Melanin Black-45,Melan-A,and S-100.Moreover,the tumor cells lacked melanin pigment;thus,a diagnosis of amelanotic AMM was made.Although the AMM had massively invaded the submucosal layer and both lymphatic and venous invasion were present,we closely monitored the patient without any additional therapy on the basis of her request.Six months after ESD,local recurrence was detected,and the patient consented to wide local excision.CONCL USION It is suggested that ESD is a potential diagnostic and treatment method for AMM.

Retrospective analysis of perianal Paget's disease with underlying anorectal carcinoma

AIM:To analyze clinical and pathological characteristics of an aggressive subtype of perianal Paget's disease(PPD) and explore its rational treatment modalities.METHODS:PPD patients were retrospectively collected in the institutional colorectal database of the Fudan University Shanghai Cancer Center.Detailed patient histories of past medical condition,diagnosis,treatment,and pathological findings were reviewed.Surgical specimen from diagnosis and surgery were reviewed by two independent pathologists for confirmation of diagnoses.Follow up was accomplished by clinical interview by cellphone.RESULTS:In total,eight cases of PPD were analyzed.All patients had underlying anorectal adenocarcinoma,including seven with synchronous lesions and one with metachronous lesions.Moreover,all anorectal lesions had a mucin-producing component.The median age at diagnosis was 65(range 29-81 years),and the male/female ratio was 7:1.The Median follow-up time of all patients was 61.5 mo(range 10-204 mo).One patient treated with abdominoperineal resection(APR) died from lung metastases 10 mo after the APR operation.The other patients are still free of disease at the time of this analysis.CONCLUSION:PPD is a rare malignancy and is easily misdiagnosed.Underlying anorectal cancer was not unusual and was a significant prognostic factor.Rational treatment of both anorectal cancer and PPD lesion is essential for long-term survival.

Neonatal colon perforation due to anorectal malformations: Can it be avoided?

Anorectal malformations (ARM) are common anomalies in neonates. Diagnostic and therapeutic delays in the management of ARM may lead to colonic perforation, and even death. Physical examination of the perineum is often sufficient to diagnose ARM in neonates. Notwithstanding, delayed diagnosis of ARM has become increasingly familiar to surgeons, as evidenced by the number of recent publications on this topic in the literature. In this commentary, we discuss spontaneous colonic perforation due to delayed diagnosis of ARM in neonates, and highlight the importance of early diagnosis in assuring good outcomes with surgical management. At this point, a thorough examination of the perineum during the initial newborn assessment is mandatory, particularly in those patients presenting with abdominal signs or symptoms.

What every gastroenterologist needs to know about common anorectal disorders

Anorectal complaints are very common and are caused by a variety of mostly benign anorectal disorders.Many anorectal conditions may be successfully treated by primary care physicians in the outpatient setting,but patients tend not to seek medical attention due to embarrassment or fear of cancer.As a result,patients frequently present with advanced disease after experiencing significant decreases in quality of life.A number of patients with anorectal complaints are referred to gastroenterologists.However,gastroenterologists' knowledge and experience in approaching these conditions may not be sufficient.This article can serve as a guide to gastroenterologists to recognize,evaluate,and manage medically or non-surgically common benign anorectal disorders,and to identify when surgical referrals are most prudent.A review of the current literature is performed to evaluate comprehensive clinical pearls and management guidelines for each topic.Topics reviewed include hemorrhoids,anal fissures,anorectal fistulas and abscesses,and pruritus ani.

Acute lower gastrointestinal bleeding from a dieulafoy lesion proximal to the anorectal junction post-orthotopic liver transplant

A 67-year-old woman underwent an orthotopic liver transplantation for end stage liver disease secondary to chronic autoimmune hepatitis. She developed sudden massive hematochezia on post-operative day 23 with hemodynamic compromise. The source of hemorrhage was found at colonoscopy after careful irrigation and inspection to be a dieulafoy lesion situated just proximal to the anorectal junction. Hemostasis was achieved with epinephrine injection and thermal coagulation.

Anorectal emergencies

Anorectal emergencies refer to anorectal disorders presenting with some alarming symptoms such as acute anal pain and bleeding which might require an immediate management. This article deals with the diagnosis and management of common anorectal emergencies such as acutely thrombosed external hemorrhoid, thrombosed or strangulated internal hemorrhoid, bleeding hemorrhoid, bleeding anorectal varices, anal fissure, irreducible or strangulated rectal prolapse, anorectal abscess, perineal necrotizing fasciitis(Fournier gangrene), retained anorectal foreign bodies and obstructing rectal cancer. Sexually transmitted diseases as anorectal non-surgical emergencies and some anorectal emergencies in neonates are also discussed. The last part of this review dedicates to the management of early complications following common anorectal procedures that may present as an emergency including acute urinary retention, bleeding, fecal impaction and anorectal sepsis. Although many of anorectal disorders presenting in an emergency setting are not life-threatening and may be successfully treated in an outpatient clinic, an accurate diagnosis and proper management remains a challenging problem for clinicians. A detailed history taking and a careful physical examination, including digital rectal examination and anoscopy, is essential for correct diagnosis and plan of treatment. In some cases, some imaging examinations, such as endoanal ultrasonography and computerized tomography scan of whole abdomen, are required. If in doubt, the attending physicians should not hesitate to consult an expert e.g., colorectal surgeon about the diagnosis, proper management and appropriate follow-up.

A Study of Anorectal Manometry in Patients with Chronic Idiopathic Constipation

To study the changes of anorectal motility in patients with chronic idiopathic constipation, anorectal motility was investigated by water-perfused manometric system in 30 patients with chronic idiopathic constipation and 18 healthy subjects. Our results showed that there was no significant dif- ference between the constipation group and the control group in anal sphincteric resting pressure and anal maximal squeezing pressure. The minimum relaxation volume, the rectal defecatory threshold, the rectal maximal tolerable volume and the rectal compliance in the patients were significantly higher than those in the controls (P< 0. 01 or P< 0. 05). It is concluded that patients with chronic idio- pathic constipation have anorectal motility disturbances.

Anorectal functional outcome after repeated transanal endoscopic microsurgery

AIM： TO evaluate the status of anorectal function after repeated transanal endoscopic microsurgery （TEN）. METHODS： Twenty-one patients undergoing subtotal colectomy with ileorectal anastomosis were included. There were more than 5 large （〉 1 cm） polyps in the remaining rectum （range： 6-20 cm from the anal edge）. All patients, 19 with villous adenomas and 2 with low-grade adenocarcinomas, underwent TEM with submucosal endoscopic excision at least twice between 2005 and 2011. Anorectal manometry and a question- naire about incontinence were carried out at week 1 before operation, and at weeks 2 and 3 and 6 mo after the last operation. Anal resting pressure, maxi- mum squeeze pressure, maximum tolerable volume （MTV） and rectoanal inhibitory reflexes （RAIR） were recorded. The integrity and thickness of the internal anal sphincter （IAS） and external anal sphincter （EAS） were also evaluated by endoanal ultrasonography. We determined the physical and mental health status with SF-36 score to assess the effect of multiple TEM on patient quality of life （QoL）. RESULTS： All patients answered the questionnaire. Apart from negative RAIR in 4 patients, all of the anorectal manometric values in the 21 patients were normal before operation. Mean anal resting pressure decreased from 38±5 mmHg to 19±3 mmHg （38±5 mmHg vs 19±3 mmHg, P = 0.000） and MTV from 165± 19mLto60± 11mL（165± 19mLvs60± 11 mL, P = 0.000） at month 3 after surgery. Anal resting pressure and MTV were 37 ± 5 mmHg （38 ± 5 mmHg vs 37 ± 5 mmHg, P = 0.057） and 159 ± 19 mL （165 ± 19 mL vs 159 ± 19 mL, P = 0.071）, respectively, at month 6 after TEM. Maximal squeeze pressure de- creased from 171 ± 19 mmHg to 62 ± 12 mmHg （171 ± 19 mmHg vs 62 ± 12 mmHg, P = 0.000） at week 2 after operation, and returned to normal values by postoperative month 3 （171 ± 19 vs 166 ± 18, P = 0.051）. RAIR were absent in 4 patients preoperatively and in 12 （χ2 = 4.947, P = 0.026） patients at month 3 after surgery. PAIR was absent only in 5 patients at postoperative month 6 （χ2 = 0.141, P = 0.707）. Endo- sonography demonstrated that IAS disruption occurred in 8 patients, and 6 patients had temporary inconti- nence to flatus that was normalized by postoperative month 3. IAS thickness decreased from 1.9 ± 0.6 mm preoperatively to 1.3 ± 0.4 mm （1.9 ± 0.6 mm vs 1.3 ± 0.4 mm, P = 0.000） at postoperative month 3 and increased to 1.8 ± 0.5 mm （1.9 ± 0.6 mm vs 1.8 ± 0.5 mm, P = 0.239） at postoperative month 6. EAS thickness decreased from 3.7 ± 0.6 mm preoperatively to 3.5 ± 0.3 mm （3.7 ± 0.6 mm vs 3.5 ± 0.3 mm, P = 0.510） at month 3 and then increased to 3.6 ± 0.4 mm （3.7 ± 0.6 mm vs 3.6 ± 0.4 mm, P = 0.123） at month 6 after operation. Most patients had frequent stools per day and relatively high Wexner scores in a short time period. While actual fecal incontinence was exceptional, episodes of soiling were reported by 3 pa- tients. With regard to the QoL, the physical and mental health status scores （SF-36） were 56.1 and 46.2 （50 in the general population）, respectively.CONCLUSION： The anorectal function after repeated TEM is preserved. Multiple TEM procedures are useful for resection of multi-polyps in the remaining rectum.

Laparoscopic abdomino-perineal resection for patients with anorectal malignant melanoma:a report of 4 cases

Anorectal malignant melanoma is a very rare but lethal disease. Patients with anorectal malignant melanoma commonly complain for changes in bowel habits and rectal bleeding. Therefore, anorectal malignant melanoma is often misdiagnosed as hemorrhoids, polyp or rectal cancer. Surgery is the mainstay of treatment for patients with anorectal malignant melanoma. However, whether abdominoperineal resection or wide local excision is the most appropriate surgical approach is still a controversial issue. Recently, with the great development of laparoscopic techniques, more and more operations can be performed by laparoscopic techniques. However, laparoscopic abdominoperineal resection for management of anorectal malignant melanoma has been rarely reported. In this study, we reported 4 patients with anorectal malignant melanoma underwent laparoscopic abdominoperineal resection. The outcomes of these patients were relatively good during a long time follow-up. Meanwhile, we reviewed the relevant studies with particular focus surgical treatment.

Effect of Modified Sinisan (四逆散) on Anorectal Manometry of the Constipation Predominant Type of Irritable Bowel Syndrome

Objective: To explore the mechanism in patients with irritable bowel syndrome (IBS) of the constipation predominant type and observe the therapeutic effects of Sinisan (四逆散, SNS). Methods: Forty -seven IBS patients with the constipation predominant type were randomly divided into the treated group ( n =24) and the control group ( n =23). Another group of 22 healthy subjects was set up for healthy control. The treated group was treated with modified SNS, and the control group was treated with Cisapride, the therapeutic course for both groups was 8 weeks. The changes of symptom scoring and anorectal manometry (the anorectal resting pressure, anal tract systolic pressure, anal tract diastolic pressure, rectal threshold feeling, maximal tolerance volume of rectum, and rectum compliance) of these two groups were recorded respectively and compared with each other. Results: Compared with the healthy control group, the rectal threshold feeling, maximal tolerance volume of rectum and rectal compliance of the treated groups got reduced significantly before treatment ( P <0.05). After treatment, the symptom scoring, rectal threshold feeling and maximal tolerance volume of rectum were improved in both groups ( P <0.05), and the improvement of the treated group was more significant than that of the control group( P <0.01). The total effective rate and recurrence rate of the treated group were superior to those of the control group significantly ( P <0.05, P <0.01).Conclusion: SNS has good effect on IBS of the constipation predominant type.

Anorectal malignant melanomas: Retrospective experience with surgical management

AIM: To present the experience and outcomes of the surgical treatment for the patients with anorectal melanoma from the Cancer Hospital, Chinese Academy of Medical Sciences. METHODS: Medical records of the diagnosis, surgery, and follow-up of 56 patients with anorectal melanoma who underwent surgery between 1975 and 2008 were retrospectively reviewed. The factors predictive for the survival rate of these patients were identified using multivariate analysis. RESULTS: The 5-year survival rate of the 56 patients with anorectal melanoma was 20%, 36 patients underwent abdominoperineal resection (APR) and 20 patients underwent wide local excision (WLE). The rates of local recurrence of the APR and WLE groups were 16.13% (5/36) and 68.75% (13/20), (P = 0.001), and the median survival time was 22 mo and 21 mo, respectively (P = 0.481). Univariate survival analysis demonstrated that the number of tumor and the depth of invasion had significant effects on the survival (P < 0.05). Multivariate analysis showed that the number of tumor [P = 0.017, 95% confidence interval (CI) = 1.273-11.075] and the depth of invasion (P = 0.015, 95% CI = 1.249-7.591) were independent prognostic factors influencing the survival rate. CONCLUSION: Complete or R0 resection is the first choice of treatment for anorectal melanoma, prognosis is poor regardless of surgical approach, and early diagnosis is the key to improved survival rate for patients with anorectal melanoma.

A anorectal fistula treatment with acellular extracellular matrix: A new technique

AIM: To investigate a new technique of the anorectal fistula treatment with acellular extracellular matrix (AEM). METHODS: Thirty patients with anorectal fistula were treated with AEM. All fistula tracts and primary openings were identified using conventional fistula probe. All tracts were curetted with curet and irrigated with hydrogen peroxide and metronidazole. The AEM was pulled into the fistula tract from secondary to primary opening. The material was secured at the level of the primary opening. The excess AEM was trimmed at skin level at the secondary opening. RESULTS: All of the 30 patients had successful closure of their fistula after a 7-14 d follow-up. The healing rate of anal fistula in treatment group was 100%. The ache time, healing time and anal deformation of treatment group were obviously superior to traditional surgical methods. CONCLUSION: Using AEM anal fistula plug in treatment that causes the anorectal fistula is safe and successful in 100% of patients. It can reduce pain, shorten disease course and protect anal function.

Iatrogenic colorectal perforation induced by anorectal manometry:Report of two cases after restorative proctectomy for distal rectal cancer

There are no reports regarding perforation of the colorectum induced by anorectal manometry. We report two cases of colorectal perforation that occurred during manometry in the patients undergoing restorative proctectomy for distal rectal cancer. In the first patient, computed tomography showed an extraperitoneal perforation in the pelvic cavity and a rupture of the rectal wall. A localized perforation into the retroperitoneum was managed conservatively. In the second patient, a 3 cm linear colon rupture was detected above the anastomotic site. A primary closure of the perforated colon and proximal ileostomy were conducted, but the patient died 2 wk later. We hypothesize that the perforation induced by anorectal manometry may be associated with the relative weakening of the proximal bowel wall due to anastomosis, decreased compliance, and abnormal rectal sensation. We suggest that measurement of the maximum tolerable volume should not be routinely performed alter restorative proctectomy for distal rectal cancer.

Rno_circ_0005139 regulates apoptosis by targeting Wnt5a in rat anorectal malformations

BACKGROUND The molecular mechanisms underlying anorectal malformations(ARM)are not fully established.Circular RNAs(circRNAs)are new born non-coding RNAs,and their role in ARM is unclear.We assumed that rno_circ_0005139 influences apoptosis and proliferation by acting as a miR-324-3p sponge,and downregulating Wnt5a in ARM.AIM To identify the differential expression of circRNAs and mRNAs in a rat ARM model.METHODS Sixty-six pregnant Wistar rats were randomly divided into two groups:ARM group(2-imidazolidinethione-induced)and control groups.Embryos were harvested by cesarean delivery,and anorectal tissue was taken on embryonic days 16(E16),17(E17),19(E19),and 21(E21).RNA sequencing and gene microarray analysis was used to identify differentially expressed circRNAs and mRNAs in the ARM in a rat model.We selected 6 circRNAs and 3 mRNAs in the Wnt signal pathway from the result of the RNA sequencing and gene microarray analysis,and quantitative reverse transcription polymerase chain reaction was performed to evaluate their tissue expression.According to bioinformatics prediction,rno_circ_0005139 acted as a miR-324-3p sponge to regulate the expression of Wnt5a.We chose rno_circ_0005139 and Wnt5a as the final candidates.We tested the function of rno_circ_0005139 and the binding sites between rno_circ_0005139 and miR-324-3p,miR-324-3p and Wnt5a by luciferase assays.Co-transfection of rno_circ_0005139 and miR-324-3p was to verify their functional consistency.RESULTS We identified 38 upregulated and 42 downregulated circRNAs on E17(P<0.05),and 301 mRNAs were upregulated and 256 downregulated in the ARM on E17(P<0.05,fold-change>2.0).We found that rno_circ_0006880 and rno_circ_0011386 were upregulated,whereas rno_circ_0000436,rno_circ_0005139,rno_circ_0009285,rno_circ_0014367,Wnt5a,Wnt10b,and Wnt2b were downregulated in ARM tissues.According to bioinformatics prediction,rno_circ_0005139 acted as a miR-324-3p sponge to regulate the expression of Wnt5a.We chose rno_circ_0005139 and Wnt5a as the final candidates.Because the role and molecular mechanism of rno_circ_0005139 are poorly understood,its effect on apoptosis and proliferation was investigated by in vitro plasmid transfection.A luciferase experiment showed that rno_circ_0005139 could bind with miR-324-3p,which negatively regulated Wnt5a expression.The expression of miR-324-3p was significantly higher in ARM anorectal tissues than that in control group on E17 and E19;Wnt5a expression showed the opposite trend.In addition,a miR-324-3p inhibitor attenuated the effects of rno_circ_0005139 knockdown on ARM development.CONCLUSION Rno_circ_0005139 influences cell proliferation and apoptosis by acting as a miR-324-3p sponge,thereby downregulating Wnt5a in ARM.Accordingly,rno_circ_0005139,miR-324-3p,and Wnt5a could be targeted therapeutic factors for ARM.

Multiple synchronous anorectal melanomas with different colors: A case report

BACKGROUND Anorectal melanoma (AM) is an extremely rare malignant tumor originating from anorectal melanocytes with a poor prognosis. AM has been reported to have a much lower incidence than cutaneous or choroid melanoma, accounting for 0.4%-1.6% of all melanomas. CASE SUMMARY We report a 76-year-old female patient diagnosed with anorectal malignant melanoma by colonoscopy and biopsy. Intraoperative examination revealed two distinct anorectal tumors, one melanotic and another amelanotic, as well as two pigmented mucosal zones at the dentate line level. Abdominal perineal resection was performed. A pathological report confirmed all four lesions to be melanomas. Postoperatively, we followed an immunotherapy protocol targeting PD-1 (nivolumab). The patient had 24 mo of disease-free follow-up upon completion of nivolumab treatment. CONCLUSION This is the first reported case presenting coexistence of pigmented and unpigmented AMs in the same patient.

Effect of 5-HT1 agonist (sumatriptan) on anorectal function in irritable bowel syndrome patients

AIM： To evaluate the effect of sumatriptan, a selective 5-HT1 agonist, on anorectal function in irritable bowel syndrome （IBS） patients. METHODS： Twenty-two IBS patients selected according to the Rome II criteria （F 15, M 7; mean age 29.3±6.8, range 22-44 years） were examined. The study was blind, randomized and placebo-controlled with a crossover design. Anorectal manometry and rectal balloon distension test were performed before and after the administration of placebo and sumatriptan. RESULTS： The administration of sumatriptan caused a significant increase in the resting anal canal pressure from 9.2±2.0 kPa to 13.1±3.3 kPa （P〈0.0001） connected with the increase in the anal sphincter length and high pressure zone. After sumatriptan injection a remarkable increase in the threshold for the first sensation from 27±9 mL to 34±12 mL （P〈0.05） and urge sensation from 61±19 mL to 68±18 mL （P〈0.01） was observed. Sumatriptan did not affect either the volume evoking the rectoanal inhibitory reflex or the results of the straining test. CONCLUSION： 5-HT1 receptors participate in the regulation of anorectal function. Elucidation of the role of 5-HT1 receptors in the pathophysiological mechanisms of IBS may have some therapeutic implications.

Trends in the management of anorectal melanoma:A multiinstitutional retrospective study and review of the world literature

BACKGROUND Anorectal melanoma(ARM)is a rare disease with a poor prognosis.Evidence on optimal treatment is limited and surgical management varies widely.We hypothesized that the frequency of abdominoperineal resection used as primary treatment of ARM has decreased over the past several decades.AIM To update our understanding of outcomes for patients with ARM and analyze management trends around the world.METHODS This is a multi-institutional,retrospective study of patients treated for ARM at 7 hospitals.Hospitals included both large,academic,tertiary care centers and smaller,general community hospitals.Using prospectively maintained institutional tumor registries,we identified 24 patients diagnosed with ARM between January 2000 and May 2019.We analyzed factors prognostic for recurrence and survival.We then used Cox regression to measure overall survival(OS)and melanoma-specific survival.We also performed a literature review to assess trends in surgical management and outcomes.RESULTS Of the 24 patients diagnosed with ARM,12(50.0%)had local,8(33.3%)regional,and 4(16.7%)distant disease at diagnosis.Median time to recurrence was 10.4 mo[interquartile range(IQR)7.5-17.2]with only 2 patients(9.3%)not developing recurrence following surgical resection.Median OS was 18.8 mo(IQR 13.5-33.9).One patient is still alive without recurrence at 21.4 mo from diagnosis;no other patient survived 5 years.Primary surgical management with abdominoperineal resection(APR)vs wide excision(WE)did not lead to differences in OS[hazard ratio=1.4(95%CI:0.3-6.8)].Review of the literature revealed geographic differences in surgical management of ARM,with increased use of WE in the United States and Europe over time and more frequent use of APR in Asia and India.There was no significant improvement in survival over time.CONCLUSION There is wide variation in the management of ARM and survival outcomes remain poor regardless of approach.Surgical management should aim to minimize morbidity.

Anorectal dysfunction in patients with mid-low rectal cancer after surgery: A pilot study with three-dimensional high-resolution manometry

BACKGROUND The quality of life in patients who develop low anterior resection syndrome(LARS)after surgery for mid-low rectal cancer is seriously impaired.The underlying pathophysiological mechanism of LARS has not been fully investigated.AIM To assess anorectal function of mid-low rectal cancer patients developing LARS perioperatively.METHODS Patients diagnosed with mid-low rectal cancer were included.The LARS score was used to evaluate defecation symptoms 3 and 6 mo after anterior resection or a stoma reversal procedure.Anorectal functions were assessed by threedimensional high resolution anorectal manometry preoperatively and 3-6 mo after surgery.RESULTS The study population consisted of 24 patients.The total LARS score was decreased at 6 mo compared with 3 mo after surgery(P<0.05),but 58.3%(14/24)lasted as major LARS at 6 mo after surgery.The length of the high-pressure zone of the anal sphincter was significantly shorter,the mean resting pressure and maximal squeeze pressure of the anus were significantly lower than those before surgery in allpatients (P < 0.05), especially in the neoadjuvant therapy group after surgery (n = 18). The focalpressure defects of the anal canal were detected in 70.8% of patients, and those patients had higherLARS scores at 3 mo postoperatively than those without focal pressure defects (P < 0.05). Spasticperistaltic contractions from the new rectum to anus were detected in 45.8% of patients, whichwere associated with a higher LARS score at 3 mo postoperatively (P < 0.05).CONCLUSIONThe LARS score decreases over time after surgery in the majority of patients with mid-low rectalcancer. Anorectal dysfunctions, especially focal pressure defects of the anal canal and spasticperistaltic contractions from the new rectum to anus postoperatively, might be the majorpathophysiological mechanisms of LARS.