Deriving optimal planning organ at risk volume margins in prostate external beam radiotherapy

Planning organ-at-risk volume (PRV) margins can be applied to the bladder and rectum in prostate external beam radiation therapy (EBRT), in order to incorporate the uncertainties resulting from their inter-fraction motion. For each of a total of 16 patients, the bladder and rectum were delineated on CBCT images for five treatment fractions in addition to the planning CT image set. The bladder and rectum boundary displacements across the images were measured and the frequency and size of organ boundary displacements were evaluated. Subsequently, PRV margins were created to cover a specific percentage of organ boundary motion for a specified percentage of the population. In this investigation, two bladder PRV margins were generated to deal with two bladder conditions of low and high-volume variation among fractions. A combined PRV margin was also generated for the rectum by separating the rectum into three parts and deriving independent PRV margins for each segment. Outward coverage and effectiveness metrics allowed evaluation of the margins.

Do clinical trials change practice? A longitudinal, international assessment of colorectal cancer prescribing practices

INTRODUCTION

Over half of the 1.5 million individuals globally who are diagnosed with colorectal cancer (CRC) present with stage II-III disease. Understanding clinician attitudes towards treatment for this group is paramount to contextualise real-world outcomes and plan future trials. The aim of this study was to assess clinician awareness of trials assessing the optimal duration of CRC adjuvant therapy, their attitudes towards shorter treatment and their self-reported practice.

METHODS

A survey was developed using OnlineSurveys® and distributed to clinicians in April 2019, with a follow-up survey disseminated to a subset of respondents in August 2020. Microsoft Excel® and Stata® were used for analysis.

RESULTS

265 clinicians replied to the first survey, with the majority aware of findings from the International Duration Evaluation of Adjuvant Therapy collaboration and contributory trials. Practice change was greatest for patients under 70 with low-risk stage III CRC, with most uncertainty around using 3-months of doublet chemotherapy for high-risk stage II disease. In August 2020, clinicians (n = 106) were more likely to use 3-months of FOLFOX for low-risk stage III disease and 3-months of CAPOX for stage II disease compared to April 2019. There was no indication that the COVID-19 pandemic had enduring changes on treatment decisions beyond those made in response to trial evidence.

DISCUSSION

Clinicians use a risk-stratified approach to treat CRC the adjuvant setting. Lower utilisation of doublet chemotherapy for older and stage II patients has affected the extent of trial implementation. Active dialogue regarding how trial results apply to these groups may improve consensus.

Evisceration of small bowel through spontaneous perforation of rectum: Case report and review of literature

INTRODUCTION

Small bowel evisceration through spontaneous perforation of the rectum is an extremely rare condition in which the small bowel herniates mostly through a defect in the anterior rectal wall.

CASE PRESENTATION

We present the case of a 25-year-old otherwise healthy lady who denied any history of rectal prolapse or trauma.

DISCUSSION

Small bowel evisceration through rectum is a rare surgical emergency with a mortality rate as high as 42.3%. Apart from trauma, chronic constipation, rectal prolapse, presence of a deep Douglas pouch and a sliding hernia formed by the cul-de-sac have also been described as etiological factors.

CONCLUSION

It is extremely difficult to find out the actual cause of "spontaneous" small bowel evisceration, especially in young adults.

PEComa in the rectum: A case report and review of the literature on epithelioid angiomyolipoma

Introduction and importance

Perivascular epithelioid cell tumor (PEComa), especially angiomyolipoma (AML) is a rare mesenchymal tumor in wide array of anatomic locations such as the kidney, lung, uterus, and gastrointestinal tract. AML is commonly found in the kidneys and classified as a classic AML or epithelioid AML. We report a case of epithelioid AML diagnosed in the rectum, treated by robot assisted low anterior resection.

Presentation of case

A 45-year-old woman was referred to our hospital because when an intramural rectal mass was detected on a colonoscopic examination performed during a regular health checkup. Colonoscopic examination revealed an intramural mass, 2 cm in diameter, bulging in the rectal wall, 6 cm from the anal verge. Based on abdominal and pelvic computed tomography images and magnetic resonance imaging findings, the patient was suspected of having gastrointestinal stromal tumor of the rectum. The patient was treated by robot assisted low anterior resection under the diagnosis of GIST. The patient improved without any postoperative complication and was diagnosed as epithelioid AML, a type of PEComa.

Discussion

AML diagnosed in gastrointestinal tract is very rare and among them, epithelioid AML has possibility of malignancy. However, confirmed diagnosis before surgical resection is difficult because PEComa shows nonspecific imaging characteristics. Treatment of choice of epithelioid angiomyolipoma is surgical resection.

Conclusion

Because epithelioid AML has the potential for malignancy, clinicians must be aware of the knowledge of the characteristics and natural history of epithelioid AML.

•

PEComa is collection of tumors arising in wide array of anatomic locations.

•

AML is the most common PEComa and 7% of AML cases are epithelioid type.

•

Our patient had AML clinically resembling GIST in rectum.

•

Surgical removal and biopsy are the only methods of diagnosing PEComa and AML.

•

Clinicians must be mindful of the characteristics of PEComa and AML.

Recurrence After Endoscopic Resection of Small Rectal Neuroendocrine Tumors: A Retrospective Cohort Study

Purpose

According to the European Neuroendocrine Tumor Society consensus guidelines, rectal neuroendocrine tumors (NETs) up to 10 mm in size and without poor prognostic factors could be safely removed with endoscopic resection, suggesting omitting surveillance colonoscopy after complete resection. However, the benefit of surveillance colonoscopy is still unknown. In this study, we aimed to report the outcomes after endoscopic resection of small rectal NETs using our surveillance protocol.

Methods

This retrospective cohort study included patients who underwent endoscopic resection for rectal NETs sized up to 10 mm from January 2013 to December 2019 at our center. We excluded patients without surveillance colonoscopy and those lost to follow-up. We strictly performed surveillance colonoscopy 1 year after endoscopic resection, and every 2 to 3 years thereafter. The primary outcomes were tumor recurrence and occurrence of metachronous tumors during follow-up.

Results

Of the 54 patients who underwent endoscopic resection for rectal NETs during the study period, 46 were enrolled in this study. The complete resection rates by endoscopic mucosal resection, precutting endoscopic mucosal resection, and endoscopic submucosal dissection were 92.3% (12 of 13), 100% (21 of 21), and 100% (12 of 12), respectively. There was no local or distant recurrence during the median follow-up of 39 months. However, we found that 8.7% (4 of 46) of patients developed metachronous NETs. All metachronous lesions were treated with precutting endoscopic mucosal resection.

Conclusion

Surveillance colonoscopy is reasonable after endoscopic resection of small rectal NETs for timely detection and treatment of metachronous lesions. However, larger collaborative studies are needed to influence the guidelines.

Transanal approach after preoperative imatinib treatment of a rectal gastrointestinal stromal tumors with external anal sphincter invasion: A case report

INTRODUCTION AND IMPORTANCE

Rectal gastrointestinal stromal tumors (GISTs) are rare, and preserving anorectal function can be challenging. We report the case of a patient with rectal GIST with external anal sphincter invasion, treated via the laparoscopic and transanal approaches.

CASE PRESENTATION

A 61-year-old man with locally advanced GIST in the right anterolateral wall of the lower rectum was examined. Lower endoscopy revealed a 50-mm submucosal tumor located 4 cm from the anal verge. On immunohistochemistry, the biopsy specimen tested positive for CD34 and C-KIT, and the patient was diagnosed with GIST. Abdominal magnetic resonance imaging (MRI) revealed external anal sphincter infiltration. Because of the large tumor size and proximity to the anal verge, preserving the anus was challenging, and colorectal resection was avoided. Instead, neoadjuvant therapy with imatinib was administered to facilitate local resection of the tumor. Post-treatment MRI showed a reduction in tumor size (30 × 20 × 30 mm), and surgery was performed. We identified an appropriate resection line for diplomatic sphincter resection of the infiltrated area by laparoscopy alone. Thus, we performed a hybrid surgery using the laparoscopic and transanal approaches. The patient had an unremarkable postoperative course and was discharged on postoperative day 23.

CLINICAL DISCUSSION

No study has reported cases of rectal GIST with external anal sphincter invasion wherein anal function was preserved. Here, imatinib was administered preoperatively, and hybrid surgery was performed using the transanal and laparoscopic approaches.

CONCLUSION

Preoperative treatment and surgery preserved anorectal function in a patient with a massive rectal GIST.

Evaluation of radical surgical treatment in the management of 58 locally advanced rectal neuroendocrine neoplasms, one multicenter retrospective study

BACKGROUND

Locally advanced rectal neuroendocrine neoplasms (NENs) are rare, and the therapeutic effects of surgery in improving the prognosis have been questioned in previous reports.

MATERIALS AND METHODS

The research included 58 consecutive patients with locally advanced rectal NENs from three Chinese medical centers between 2000 and 2020. All have received radical surgical treatment. The clinicopathological and survival data were collected. Kaplan-Meier methods and a Cox proportional hazards regression model were used to evaluate the prognosis and identify independent prognostic factors.

RESULTS

All patients were followed up for a median period of 36 (2-125) months. Of the 58 patients, 13 (22.4%) had G1 neuroendocrine tumors (NETs), 15 (25.9%) had G2 NETs, 6 (10.3%) had G3 NETs, and the remaining 24 (41.4%) patients had G3 neuroendocrine carcinomas (NECs). The 1-year and 3-year disease-free survival (DFS) rates were 64.5% and 48.8%, respectively. The 1-year and 3-year overall survival (OS) rates were 90.5% and 75.4%, respectively. Univariate analysis demonstrated that tumor differentiation (p = 0.002), gross morphology (p = 0.009), T stage (p = 0.024), and extramural vascular invasion (p = 0.009) were associated with the OS. The subsequent multivariate analysis confirmed that tumor differentiation [hazard ratio (HR) = 6.002, 95% confidence interval (CI): 1.210-29.767, p = 0.028] and gross morphology (HR = 3.438, 95% CI: 1.038-11.382, p = 0.043) were independent prognostic factors affecting the clinical outcomes.

CONCLUSIONS

Rectal NENs are a heterogeneous group of diseases. The survival benefits obtained from surgery vary widely based on the tumor clinicopathological features. Patients with G3 NECs and ulcerative mass are at high risks of poor prognosis.

Chylous ascites in colorectal surgery: A systematic review

BACKGROUND

Chylous ascites is a rare complication in colorectal surgery with limited evidence.

AIM

To systematically review all available evidence to describe the incidence, clinical presentation, risk factors and management strategies.

METHODS

The systematic review was performed through PubMed, MEDLINE, EMBASE and Cochrane and cross-checked up to November 2020. The data collated included: Demographics, indications (benign vs malignant), site of disease, surgical approach, extent of lymphadenectomy, day to and method of diagnosis of chylous ascites and management strategies.

RESULTS

A total of 28 studies were included in the final analysis (426 cases). Patient age ranged from 31 to 89 years. All except one case were performed for malignancy. Of the 426 cases, 195 were right-colonic, 121 left-colonic, 103 pelvic surgeries and 7 others. The majority were diagnosed during the same inpatient stay by recognition of typical drain appearance and increased volume. Three cases were diagnosed during outpatient visits with increased abdominal distention and subsequently underwent paracentesis. Most cases were managed successfully non-operatively (fasting with prolonged drainage, total parenteral nutrition, somatostatin analogues or a combination of these). Only three cases required surgical intervention after failing conservative management and subsequently resolved completely. Risk factors identified include: Right-colonic surgery/ tumour location, extent of lymphadenectomy and number of lymph nodes harvested.

CONCLUSION

Chylous ascites after colorectal surgery is a relatively rare complication. Whilst the majority of cases resolved without surgical intervention, preventative measures should be undertaken such as meticulous dissection and clipping of lymphatics during lymphadenectomy to prevent morbidity.

Collision carcinoma of the rectum involving neuroendocrine carcinoma and adenocarcinoma: A case report

BACKGROUND

Collision carcinoma is a rare histological pattern, and includes two or more different types of tumors coexisting in the same organ as one neoplasm. Different to the combined type, the two adjacent tumors of collision carcinoma are histologically distinct. Collision carcinoma may occur from any origin or organ, including the cecum, liver, cervix, thyroid, stomach, kidney, and esophagus. In the rectum, adenocarcinoma is the most common pathological type, the combined type is rare, and collision tumors are even rarer. To date, only a limited number of collision carcinoma cases originating from the rectum have been reported. Due to the scarcity of rectal collision carcinoma, more cases need to be reported to fully understand the clinico-pathological features and biological behavior of the tumor.

CASE SUMMARY

Here we report a 40-year-old female who presented with the chief complaints of persistent changes in bowel habits and hematochezia for 10 d. She underwent Miles' operation which revealed a collision carcinoma of the rectum, showing a “side by side” pattern, composed of a high grade neuroendocrine carcinoma, (small cell carcinoma) and moderately differentiated adenocarcinoma, based on its clinico-pathological features and biological behavior. The patient remained disease-free at 12 mo follow-up. We also focused on the related literature and expert opinion.

CONCLUSION

Collision carcinoma is a rare tumor with ambiguous biological behavior. Greater attention should be paid to its clinico-pathologic diagnosis. Regular and adequate follow-up is essential to help rule out metastasis and assess the prognosis.

Risk of Rectovaginal Fistula in Women with Excision of Deep Endometriosis Requiring Concomitant Vaginal and Rectal Sutures, with or without Preventive Stoma: A Before-and-after Comparative Study

STUDY OBJECTIVE

To assess whether a liberal policy of preventive stoma (LPS) reduces the rate of rectovaginal fistulas in women with excision of deep endometriosis requiring concomitant vaginal and rectal sutures in comparison with a more restrictive policy of preventive stoma (RPS) and to assess the risk factors for rectovaginal fistula.

DESIGN

Retrospective before-and-after comparative study.

SETTING

Two referral centers, one with an LPS and the other with an RPS.

PATIENTS

A total of 363 patients with deep endometriosis infiltrating the rectum and the vagina.

INTERVENTIONS

Rectal disc excision or colorectal resection concomitantly with vaginal excision.

MEASUREMENTS AND MAIN RESULTS

Two hundred forty-one and 122 women received surgery at the LPS and RPS centers, respectively. The rate of preventive stomas was 71.4% at the LPS center (n = 172) and 30.3% at the RPS center (N = 37). Rectovaginal fistula was recorded in 31 cases (8.5%): nineteen women were managed at the LPS center, and 12 women underwent surgery at the RPS center. It occurred in, respectively, 9.4%, 10.8%, 10.1%, and 7% of the women managed without and with a stoma at the RPS center and of those managed without and with a stoma at the LPS center (p = .72). The height of the rectal stapled line was significantly lower in the women undergoing a stoma, particularly in those managed at the RPS center (5.4 ± 1.8 cm). Performing rectal sutures within 8 cm from the anal verge increased the risk of rectovaginal fistula more than 3-fold, independently of stoma creation, surgical procedure carried out on the rectum, size of vaginal infiltration, or associated excision of deep endometriosis involving the pelvic nerves (odds ratio 3.4; 95% confidence interval, 1.3-9.1).

CONCLUSION

No statistically significant differences were found in terms of the risk of rectovaginal fistula between women with rectovaginal endometriosis managed by either an LPS or an RPS; however, these findings need to be confirmed by a randomized trial.

Tumor grade 2 as the independent predictor for lymph node metastasis in 10-20 mm sized rectal neuroendocrine tumor

Purpose

Rectal neuroendocrine tumors (NETs) <10 mm are endoscopically resected, while those ≥20 mm are treated with radical surgical resection. The choice of treatment for 10-20 mm sized rectal NETs remains controversial. This study aimed to verify factors predicting lymph node metastasis (LNM) of 10-20 mm sized rectal NET and utilize them to decide upon the treatment strategy.

Methods

Twenty-eight patients with 10-20 mm sized rectal NETs treated at Pusan National University Yangsan Hospital from January 2009 to September 2020 were divided into LNM (+) and LNM (-) groups, and their respective data were analyzed.

Results

Seven patients (25%) had LNM while 21 patients (75%) did not. Endorectal ultrasound findings showed tumor size was significantly larger in the LNM (+) than in the LNM (-) group (15 mm vs. 10 mm, P=0.018); however, pathologically, there was no significant difference in tumor size (13 mm vs. 11 mm, P=0.109). The mitotic count (P=0.011), Ki-67 index (P=0.008), and proportion of tumor grade 2 patients (5 cases, 71% vs. 1 case, 5%; P=0.001) were significantly higher in the LNM (+) group. In multivariate analysis, tumor grade 2 was the independent factor predicting LNM (odds ratio, 61.32; 95% confidence interval, 3.17-1,188.64; P=0.010).

Conclusion

Tumor grade 2 was the independent factor predicting LNM in 10-20 mm sized rectal NETs. Therefore, it could be considered as the meaningful factor in determining whether radical resection is necessary.

Rectal neuroendocrine tumor with extracapsular lymph node metastasis: a case report

The presence of extramural tumor deposits without lymph node structure (EX) is an important prognostic factor in patients with colorectal carcinoma. However, there is no English literature on neuroendocrine tumor (NET) with EX. We report a patient with rectal NET with extracapsular metastasis of a regional lymph node that was considered to be EX. A 51-year-old Japanese woman with diabetes was referred to our hospital for further examination of a submucosal tumor in the lower rectum. She was diagnosed as having rectal NET by immunohistochemical analysis of a biopsy, and underwent laparoscopic low anterior resection with lymph node dissection and covering ileostomy. Pathological findings of the resected specimen showed that the primary tumor was NET-G1 without any lymphatic or venous invasion. A single metastatic deposit was found near the capsule of a NET-negative regional lymph node. She has been free from recurrence for nine months without adjuvant treatments. Extracapsular metastasis of NET on a dissected lymph node in our case was considered to correspond to EX as defined for colorectal carcinoma. This rare case suggests that NET can disseminate to form EX in a similar manner to colorectal carcinoma.

Oncological outcomes according to the treatment modality based on the size of rectal neuroendocrine tumors: a single-center retrospective study

BACKGROUND

Owing to an increased number of colonoscopy screenings, the incidence of diagnosed rectal neuroendocrine tumors (NETs) has also increased. Tumor size is one of the most frequently regarded factors when selecting treatment; however, it may not be the determinant prognostic variable. We aimed to evaluate oncological outcomes according to the treatment modality based on the size of rectal NETs.

METHODS

A retrospective analysis was performed on patients who were treated for rectal NETs between March 2000 and January 2016 at the Asan Medical Center, Seoul, Korea. Patients who underwent endoscopic removal, local surgical excision, and radical resection were included. The primary outcome was recurrence-free survival (RFS). Data were specified and analyzed following the 2019 World Health Organization classification (WHO).

RESULTS

A total of 644 patients were categorized under three groups according to the treatment modality used: endoscopic removal (n = 567), surgical local excision (n = 56), and radical resection (n = 21). Of a total of 35 recurrences, 27 were local, whereas eight were distant. The RFS rate did not differ significantly between the treatment groups in the same tumor-size group ([Formula: see text]1 cm group: P = .636, 1-2 cm group: P = .160). For T1 tumors, RFS rate was not different between local excision and radical resection ([Formula: see text]1 cm group: P = .452, 1-2 cm group: P = .700). Depth of invasion, a high Ki-67 index, and margin involvement were confirmed as independent risk factors for recurrence. Among patients treated with endoscopic removal, endoscopic biopsy was a significant factor for worse RFS (P < .001), while tumor size did not affect the RFS.

CONCLUSION

The current guideline recommends treatment options according to tumor size. However, more oncologically important prognostic factors include muscularis propria invasion and a higher Ki-67 index.

Colonoscopic Polypectomy Preferences of Asian Endoscopists: Results of a Survey-Based Study

Background/Aims

The clinical practice pattern of polypectomy is not well-investigated in Asian countries. We aimed to survey Asian endoscopists about their preferred polypectomy techniques for given conditions and images of polyps.

Methods

A survey was performed using questionnaires composed of two parts a scenario-based questionnaire using scenarios of polyps, which were adopted from the European Society of Gastrointestinal Endoscopy guidelines, and an image-based questionnaire using provided endoscopic images of polyps.

Results

A total of 154 endoscopists participated in this survey. The most preferred resection techniques for diminutive (≤5 mm), small (6–9 mm), and benign-looking intermediate (10–19 mm) nonpedunculated polyps were cold forceps polypectomy, hot snare polypectomy, and endoscopic mucosal resection (EMR), respectively, in both the scenario- and image-based questionnaires. For benign-looking large (≥20 mm) nonpedunculated polyps, EMR and endoscopic submucosal dissection (ESD) were preferred in the scenario- and image-based surveys, respectively. In case of malignant nonpedunculated polyps, EMR and ESD were preferred for intermediate-sized and large lesions, respectively, according to the scenario-based survey. However, ESD was preferred in both intermediate-sized and large malignant nonpedunculated polyps according to the image-based survey. Trainee endoscopists, endoscopists working in referral centers, and endoscopists in the colorectal cancer–prevalent countries were independently associated with preference of cold snare polypectomy for removing small polyps.

Conclusions

The polypectomy practice patterns of Asian endoscopists vary, and cold snare polypectomy was not the most preferred resection method for polyps <10 mm in size, in contrast to recent guidelines. (Gut Liver 2021;15-400)

Prevalence of Group B Streptococcus in Vagina and Rectum of Pregnant Women of Islamic & Non-Islamic Countries: A Systematic Review and Meta-Analysis

Background

Group B streptococcus or streptococcus Agalactia is a gram positive beta hemolytic bacteria which is the main factor in neonatal infections. This study aimed at determining the prevalence of GBS in world and clarifying the rate of this infection in Islamic and non-Islamic countries.

Methods

We performed a systematic search by using different databases including Medline, Scopus, Science Direct, Psycho-Info ProQuest and Web of Science published up to Feb 2019. We undertook meta-analysis to obtain the pooled estimate of prevalence of GBS colonization in Islamic and non-Islamic countries.

Results

Among 3324 papers searched, we identified 245 full texts of prevalence of GBS in pregnancy; 131 were included in final analysis. The estimated mean prevalence of maternal GBS colonization was 15.5% (CI:95% (14.2-17)) worldwide; which was 14% (CI:95% (11-16.8)) in Islamic and 16.3% (CI:95% (14.6-18.1)) in non-Islamic countries and was statistically significant. Moreover, with regards to sampling area, prevalence of GBS colonization was 11.1 in vagina and 18.1 in vagina-rectum.

Conclusion

Frequent washing of perineum based on religious instructions in Islamic countries can diminish the rate of GBS colonization in pregnant women.

Reducing dose to rectum by placement of a rectum-emptying tube in cervical cancer patients treated with brachytherapy

PURPOSE

Only scarce data are available on the possibility to reduce rectal dose by controlling rectum filling before HDR (high dose rate) IGABT (image-guided adaptive brachytherapy) in LACC (locally advanced cervical carcinoma) patients. We compared dosimetric outcomes before and after the evacuation of gasses using a rectum emptying tube.

METHODS AND MATERIAL

Sixty CT (computed tomography) scans from 30 consecutive patients with cancer of the cervix undergoing HDR IGABT after EBRT were reviewed. Patients who underwent at least one gas evacuation were included in the analysis. The three-dimensional dosimetric data of the dosimetric plan performed before and after gas evacuation were compared. Primary endpoint was the difference between D2cc of the rectum before and after the procedure. Expected probability of grade 2-4 overall rectum morbidity was assessed using a probit model from the prospective multicenter EMBRACE study.

RESULTS

Thirty five (58.3%) CT scans from 23 patients (76.7%) requiring gas evacuation were analysed. The mean rectum volume, before and after gas evacuation, was 123.1 cc (sd, ± 60.4) and 66.4 cc (sd, ± 34.8), respectively. For each patient, the volume of the rectum after gas evacuation was lower than before. No major complication occurred during and after the procedure. After gas evacuation, a significant reduction in rectal dose per fraction was observed, on average -4.3 Gy (-38.4%, p < 0.001) for D0.1cc and -1.9 Gy (-30.6%, p < 0.001) for D2cc. Estimated mean probability to develop a grade 2-4 rectum morbidity was significantly lower after gas evacuation, 6.9% (sd,± 1.94) versus 9.5% (sd,± 3.17), p < 0.001.

CONCLUSION

Gas evacuation using a rectal emptying tube in selected LACC patients treated with HDR BT after chemoradiotherapy, allowed a substantial reduction in the dose to the rectum. Such procedure could be of particular interest when a dose escalation strategy is being considered.

Adherence to Surveillance Guidelines after the Removal of Colorectal Polyps: A Multinational, Multicenter, Prospective Survey

Background/Aims

As the number of colonoscopies and polypectomies performed continues to increase in many Asian countries, there is a great demand for surveillance colonoscopy. The aim of this study was to investigate the adherence to postpolypectomy surveillance guidelines among physicians in Asia.

Methods

A survey study was performed in seven Asian countries. An email invitation with a link to the survey was sent to participants who were asked to complete the questionnaire consisting of eight clinical scenarios.

Results

Of the 137 doctors invited, 123 (89.8%) provided valid responses. Approximately 50% of the participants adhered to the guidelines regardless of the risk of adenoma, except in the case of tubulovillous adenoma ≥10 mm combined with high-grade dysplasia, in which 35% of the participants adhered to the guidelines. The participants were stratified according to the number of colonoscopies performed ≥20 colonoscopies per month (high volume group) and <20 colonoscopies per month (low volume group). Higher adherence to the postpolypectomy surveillance guidelines was evident in the high volume group (60%) than in the low volume group (25%). The reasons for nonadherence included concern of missed polyps (59%), the low cost of colonoscopy (26%), concern of incomplete resection (25%), and concern of medical liability (15%).

Conclusions

A discrepancy between clinical practice and surveillance guidelines among physicians in Asia was found. Physicians in the low volume group frequently did not adhere to the guidelines, suggesting a need for continuing education and appropriate control. Concerns regarding the quality of colonoscopy and complete polypectomy were the main reasons for nonadherence.

Unusual Presentation of Anal Pain and Tenesmus from Rectal Arteriovenous Malformation Successfully Treated with Ethanol Sclerotherapy

Gastrointestinal arteriovenous malformation (AVM) is reported as one of the possible causes of intestinal bleeding, and its occurrence in the rectum is rare. We report the case of a rectal AVM patient who experienced uncommon symptoms of anal pain and tenesmus and was treated successfully with percutaneous transarterial ethanol sclerotherapy. The patient underwent routine colonoscopy with biopsy at the time of visit; however, an accurate diagnosis was difficult. Subsequent contrast-enhanced computed tomography (CT) and angiography revealed a rectal AVM emerging from the distal inferior mesenteric artery with engorged superior rectal veins. The feeding artery was catheterized, and concurrent transarterial sclerotherapy with 80% ethanol was performed. There was no major complication related to the procedure. Disappearance of AVM nidus and improvement of associated venous congestion were shown by follow-up CT. There was no recurrence of symptoms after 10 months of clinical observation. Transarterial ethanol sclerotherapy is safe and effective in treating rectal AVM and can be considered as one of the nonsurgical treatment options.

Giant polyploid epidermal cells and male pheromone production in the tephritid fruit fly Eurosta solidaginis (Diptera: Tephritidae)

Eurosta solidaginis males produce large amounts of putative sex pheromone compared to other insect species; however, neither the site of pheromone production nor the release mechanism has been characterized. We compared E. solidaginis males and females, focusing on sexually dimorphic structures that are known to be involved in pheromone production in other tephritid species. Morphological and chemical analyses indicated that the rectum and pleural epidermis are involved in male E. solidaginis pheromone production, storage, or emission. We detected large quantities of pheromone in the enlarged rectum, suggesting that it stores pheromone for subsequent release through the anus. However, pheromone might also discharge through the pleural cuticle with the involvement of unusual pleural attachments of the tergosternal muscles, which, when contracted in males, realign specialized cuticular surface elements and expose less-sclerotized areas of cuticle. In males, pheromone components were also detected in epidermal cells of the pleuron. These cells were 60-100 times larger in mature males than in females and, to our knowledge, are the largest animal epithelial cells ever recorded. Furthermore, because these large cells in males are multinucleated, we presume that they develop through somatic polyploidization by endomitosis. Consequently, the pheromone-associated multinuclear pleural epidermal cells of Eurosta solidaginis may provide an interesting new system for understanding polyploidization.

Endoscopically removed rectal NETs: a nationwide cohort study

PURPOSE

Rectal neuroendocrine tumours (NETs) often present as an incidental finding during colonoscopy. Complete endoscopic resection of low-grade NETs up to 10 mm is considered safe. Whether this is also safe for NETs up to 20 mm is unclear. We performed a nationwide study to determine the risk of lymph node and distant metastases in endoscopically removed NETs.

METHODS

All endoscopically removed rectal NETs between 1990 and 2010 were identified using the national pathology database (PALGA). Each NET was stratified according to size, grade and resection margin. Follow-up was until February 2016.

RESULTS

Between 1990 and 2010, a total of 310 NETs smaller than 20 mm were endoscopically removed. Mean size of NETs was 7.4 mm (SD 3.5). In 49% of NETs (n = 153), no grade (G) could be assessed from the pathology report, 1% was G2 (n = 3), and the remaining NETs were G1. Median follow up was 11.6 years (range 4.9-26.0). During follow-up, 30 patients underwent surgical resection. Lymph node or distant metastasis was seen in 3 patients (1%) which all had a grade 2 NET. Mean time from endoscopic resection to diagnosis of metastases was 6.1 years (95% CI 2.9-9.2).

CONCLUSION

No lymph node or distant metastases were seen in endoscopically removed G1 NETs up to 20 mm during the long follow-up of this nationwide study. This adds evidence to the ENET guideline that endoscopic resection of G1 NETs up to 20 mm appears to be safe.

Meta-analysis of biological mesh reconstruction versus primary perineal closure after abdominoperineal excision of rectal cancer

BACKGROUND

Extralevator abdominoperineal excision (ELAPE) of rectal cancer has been proposed to achieve better oncological outcomes. The resultant wide perineal wound, however, presents a challenge for primary closure and subsequent wound healing. This meta-analysis compared the outcomes of primary perineal closure with those of biological mesh reconstruction.

METHODS

The Medline and Embase search was performed for the publications comparing primary perineal closure to biological mesh reconstruction. Early perineal wound complications (seroma, infection, dehiscence) and late perineal wound complications (perineal hernia, chronic pain, and chronic sinus) were analyzed as primary endpoints. Intraoperative blood loss, operation time, and hospital stay were compared as secondary endpoints.

RESULTS

There was no significant difference in the overall early wound complications after primary closure or biological mesh reconstruction (odds ratio (OR) of 0.575 with 95% confidence interval (CI) of 0.241 to 1.373 and a P value of 0.213). The incidence of perineal hernia after 1 year was significantly high after primary closure of the perineal wounds (OR of 0.400 with 95% CI of 0.240 to 0.665 and a P value of 0.001). No significant differences were observed among other early and late perineal wound complications. The operation time and hospital stay were shorter after primary perineal closure (p 0.001).

CONCLUSION

A lower incidence of perineal hernia and comparable early perineal wound complications after biological mesh reconstruction show a relative superiority over primary closure. More randomized studies are required before a routine biological mesh reconstruction can be recommended for closure of perineal wounds after ELAPE.

Association between Texture Analysis Parameters and Molecular Biologic KRAS Mutation in Non-Mucinous Rectal Cancer

Purpose

To evaluate the association between magnetic resonance imaging (MRI)-based texture parameters and Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation in patients with non-mucinous rectal cancer.

Materials and Methods

Seventy-nine patients who had pathologically confirmed rectal non-mucinous adenocarcinoma with or without KRAS-mutation and had undergone rectal MRI were divided into a training (n = 46) and validation dataset (n = 33). A texture analysis was performed on the axial T2-weighted images. The association was statistically analyzed using the Mann-Whitney U test. To extract an optimal cut-off value for the prediction of KRAS mutation, a receiver operating characteristic curve analysis was performed. The cut-off value was verified using the validation dataset.

Results

In the training dataset, skewness in the mutant group (n = 22) was significantly higher than in the wild-type group (n = 24) (0.221 ± 0.283; -0.006 ± 0.178, respectively, p = 0.003). The area under the curve of the skewness was 0.757 (95% confidence interval, 0.606 to 0.872) with a maximum accuracy of 71%, a sensitivity of 64%, and a specificity of 78%. None of the other texture parameters were associated with KRAS mutation (p > 0.05). When a cut-off value of 0.078 was applied to the validation dataset, this had an accuracy of 76%, a sensitivity of 86%, and a specificity of 68%.

Conclusion

Skewness was associated with KRAS mutation in patients with non-mucinous rectal cancer.

A tailored approach to abdominoperineal resection for rectal cancer: multicentre analysis of short-term outcomes and impact on oncological survival

PURPOSE

Abdominoperineal resection of the rectum has evolved over the last century, with few modifications until 2007, when extralevator abdominoperineal resection was introduced, which improved local disease control but resulted in a significant rise in perineal complications. We adopted a modified approach in which dissection was tailored according to magnetic resonance-defined tumour involvement. The aim of this study was to assess short-term and long-term oncological outcomes following a tailored abdominoperineal resection (APR) approach.

METHODS

This study was a retrospective review of prospectively maintained databases at three centres: Portsmouth NHS Trust (UK), Poole General Hospital (UK) and Champalimaud's Cancer Foundation, Portugal. The study included consecutive patients who underwent abdominoperineal resection from October 2008 until April 2018 under the supervision of the senior author. Oncological outcomes, including overall survival and disease-free survival, were used as the main outcome measures.

RESULTS

A total of 584 patients underwent rectal cancer surgery during the study period. The APR ratio was 65/584 (11%). The median age was 66 years. Neoadjuvant treatment was administered to 74% of patients. Of the patients, 91% underwent surgery via a minimally invasive approach. The median hospital stay was 7 days. Patients were followed up for a median of 41 months. Only four patients had positive resection margins. The 5-year overall and disease-free survival rates were 64% and 62%, respectively.

CONCLUSION

Our data suggest that tailored APR has similar short-term and long-term oncological outcomes compared with extralevator abdominoperineal resection but reduced perineal wound complications. We believe this approach could be a safe alternative but recommend a larger sample size to accurately assess its effectiveness.

The impact of surgical approach on short- and long-term outcomes after rectal cancer resection in elderly patients: a national cancer database propensity score matched comparison of robotic, laparoscopic, and open approaches

BACKGROUND

Elderly patients are underrepresented in studies demonstrating the advantages of laparoscopy for the management of colorectal diseases. Moreover, few studies have examined the robotic approach in this population. In this retrospective analysis, we compare outcomes for open, laparoscopic, and robotic approaches in elderly patients with nonmetastatic rectal cancer.

METHODS

The U.S. National Cancer Database was queried for patients aged ≥ 65 with nonmetastatic adenocarcinoma of the rectum who underwent surgical resection from 2010 to 2016. Groups were separated based on approach (open, laparoscopic, robotic). One-to-one nearest neighbor propensity score matching (PSM) ± 1% caliper was performed across surgical approach cohorts to balance potential confounding covariates. Kaplan-Meier estimation and Cox-proportional hazards regression were used to analyze the primary outcome of survival. Secondary outcomes were analyzed by way of logistic regression.

RESULTS

Inclusion criteria and PSM identified 1891 patients per approach (n = 5673). PSM provided adequate discrimination between cohorts (0.6 < AUC < 0.8), and potential confounding covariates did not significantly differ (respective P > 0.05). After PSM, robotic and laparoscopic approaches were associated with decreased odds of 90 day mortality compared to the open approach (P < 0.05). Compared to laparoscopy, a robotic approach was associated with increased odds of ≥ 12 regional lymph nodes examined and negative circumferential resection margin (P < 0.05). No differences were seen in 30 day or 90 day mortality between robotic and laparoscopic approaches. Cox proportional hazards regression showed that both robotic and laparoscopic approaches were significantly associated with decreased mortality hazards relative to open.

CONCLUSION

Our study demonstrates that in elderly patients, minimally invasive surgery for rectal adenocarcinoma was associated with equivalent or improved short- and long-term mortality over open surgery. Compared to laparoscopy, the robotic approach showed no survival disadvantage and greater odds of an appropriate oncological resection. Our study adds evidence to the conclusion that robotic rectal surgery can be safely performed in patients regardless of age.

Metastatic renal cell carcinoma involving colon with unusual histologic features and diagnostic challenges: A case report

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Metastatic RCC in the colon, although very rare, should be kept in the differential diagnosis of patients with lower GI bleeding, particularly patients with a prior history of kidney mass or nephrectomy

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Most common type of primary or metastatic RCC is Clear-cell-type.

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We reported the first case of rhabdoid-RCC metastasizing to colon.

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In the absence of IHC-stains, rhabdoid-RCC may be misdiagnosed as soft-tissue-sarcoma or other poorly differentiated carcinomas.

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Our case exclusively occurred in a woman while colonic metastasis of RCC commonly occurring in males.

Introduction and importance

Renal cell carcinoma (RCC) accounts for 3% of all malignancies in adults, on its own being the 3rd most common urologic malignancy. Commonly RCC metastasizes to lung, bone, liver, brain but rarely to colorectum. Here we present the metastasis of RCC to colon with unusual histologic features.

Case presentation

A 40-year-old woman presented with abdominal pain and constipation. Colonoscopy showed an ulcerative mass 30 cm from anal verge. Subsequently, she underwent abdominoperineal resection of the involved portion of colon and the biopsy was sent to us for histopathological analysis. Grossly, it was a large fungating mass. Microscopic examination revealed a malignant neoplasm with polygonal cells, abundant eosinophilic cytoplasm, eccentric nuclei and prominent nucleoli. Immunohistochemistry confirmed the diagnosis of RCC.

Clinical discussion

Colon rarely infiltrated by metastasis from RCC and so far, around 25 of such cases have been reported in the literature. Most common metastatic type of RCC to gastrointestinal tract is clear cell type. In our patient, the type of the metastatic RCC to colon was RCC with rhabdoid features. RCC with rhabdoid features is rare (3–5% of all RCC), but it is highly aggressive with higher chance of metastasis, extra renal invasion and poorer prognosis.

Conclusion

RCC should be considered as one of the differential diagnosis of colorectal cancers. Appropriate immunohistochemical workup would then reveal the correct diagnosis.