Localization of the peritoneal reflection in the pelvis by endorectal ultrasound

Validation of pelvic magnetic resonance imaging as the method of choice to determine the distance to the anal margin in rectal cancer

INTRODUCTION

Distance from anal verge of rectal tumours and their anatomical relationships contribute to determine the multidisciplinary therapeutic strategy based on the combination of radio-chemotherapy and radical surgery. Our aims are to investigate which is the most accurate method for the preoperative measuring of the distance from the anal verge in rectal tumours and if the pelvic MRI can substitute the classical instrumental methods.

METHODS

Prospective study of diagnostic precision between flexible colonoscopy (FC), preoperative rigid rectosigmoidoscopy (pRR) and pelvic MRI in patients scheduled to radical surgery. Rigid intraoperative rectoscopy (iRR) was considered the reference test. The correlations between the different techniques and their determination coefficient as well as the intraclass correlation coefficient and the degree of agreement between the different tests were analyzed.

RESULTS

96 patients (65% males), mean age (SD): 68 (14.1) years were included. 72% received neoadjuvant treatment. The mean distance to the anal margin measured by FC = 103.5 mm, was significantly greater than others, which had similar values: pRR = 81.1; MRI = 77.4; iRR = 82.9 mm (P < .001). A significant intraclass correlation was observed and there was high agreement between all pre- and intraoperative measurements except for the performed by FC, which overestimated the results. MRI provided more individualized and accurate information.

CONCLUSIONS

There is variability between the measurement methods, being colonoscopy the least reliable. MRI offers objective, comparable, accurate and individualized values that can replace those obtained by pRR for tumours of any location in the rectum.

Validation of pelvic magnetic resonance imaging as the method of choice to determine the distance to the anal margin in rectal cancer

INTRODUCTION

Distance from anal verge of rectal tumors and their anatomical relationships contribute to determine the multidisciplinary therapeutic strategy based on the combination of radio-chemotherapy and radical surgery. Our aims are to investigate which is the most accurate method for the preoperative measuring of the distance from the anal verge in rectal tumors and if the pelvic MRI can substitute the classical instrumental methods.

METHODS

Prospective study of diagnostic precision between flexible colonoscopy (FC), preoperative rigid rectosigmoidoscopy (pRR) and pelvic MRI in patients scheduled to radical surgery. Rigid intraoperative rectoscopy (iRR) was considered the reference test. The correlations between the different techniques and their determination coefficient as well as the intraclass correlation coefficient and the degree of agreement between the different tests were analyzed.

RESULTS

96 patients (65% males), mean age (SD): 68 (14.1) years were included. 72% received neoadjuvant treatment. The mean distance to the anal margin measured by FC=103.5mm, was significantly greater than others, which had similar values: pRR=81.1; MRI=77.4; iRR=82.9mm (P<.001). A significant intraclass correlation was observed and there was high agreement between all pre- and intraoperative measurements except for the performed by FC, which overestimated the results. MRI provided more individualized and accurate information.

CONCLUSIONS

There is variability between the measurement methods, being colonoscopy the least reliable. MRI offers objective, comparable, accurate and individualized values that can replace those obtained by pRR for tumors of any location in the rectum.

MRI-based nomogram analysis: recognition of anterior peritoneal reflection and its relationship to rectal cancers

Background

This study is aimed to explore the factors influencing the visualization of the anterior peritoneal reflection (APR) and evaluated the feasibility of measuring the distance from the anal verge to APR (AV-APR), the tumor height on MRI and the accuracy of determining the tumor location with regard to APR.

Methods

We retrospectively analyzed 110 patients with rectal cancer. A univariate and multivariate logistic regression was performed to identify the independent factors (age, sex, T stage, the degree of bladder filling, pelvic effusion, intraoperative tumor location, BMI, uterine orientation, the distance from seminal vesicle/uterus to rectum) associated with the visualization of the APR on MRI. The nomogram diagram and receiver operating characteristic curve (ROC curve) were established. Intraclass correlation coefficient (ICC) was used to evaluate the consistency of the distance of AV-APR. The Pearson correlation coefficient was used to characterize the agreement between measurements of the tumor height by colonoscopy and MRI. The Kappa statistics was used to evaluate the value of MRI in the diagnosis of the tumor location with regard to the APR.

Results

Multivariate logistic regression showed that BMI (P = 0.031, odds ratio, OR = 1.197), pelvic effusion (P = 0.020, OR = 7.107) and the distance from seminal vesicle/uterus to the rectum (P = 0.001, OR = 3.622) were correlated with the visualization of APR. The cut-off point of BMI and the distance from seminal vesicle/uterus to the rectum is 25.845 kg/m² and 1.15 cm. The area under curve (AUC) (95% Confidence Interval, 95% CI) of the combined model is 0.840 (0.750–0.930). The favorable calibration of the nomogram showed a non-significant Hosmer–Lemeshow test statistic (P = 0.195). The ICC value (95% CI) of the distance of AV-APR measured by two radiologists was 0.981 (0.969–0.989). The height measured by MRI and colonoscopy were correlated with each other (r = 0.699, P < 0.001). The Kappa value was 0.854.

Conclusions

BMI, pelvic effusion, and the distance from seminal vesicle/uterus to rectum could affect the visualization of APR on MRI. Also, it’s feasible to measure the distance of AV-APR, the tumor height, and to evaluate the tumor location with regard to APR using MRI.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12880-021-00583-7.

CORRELATION BETWEEN THE LEVEL OF COLORECTAL ANASTOMOSIS AND ANORECTAL FUNCTION

Anterior rectal resection is a standard surgical procedure for treating carcinomas of rectum and distal sigmoid colon. In many cases of anterior rectal resection, postoperatively some level of fecal incontinence may occur. The aim of our study was to evaluate the impact of the colorectal anastomosis level on anorectal functional disorder. In our prospective study, the participants were patients diagnosed with carcinoma of rectum or distal sigmoid colon. All patients underwent standard open or laparoscopic anterior rectal resection. Six months after the surgery, the function of anorectum was evaluated in all participants. Finally, 38 patients were analyzed, including 13/38 (34.2%) patients with high rectal anastomosis, 11/38 (28.9%) with mid rectal anastomosis and 14/38 (36.8%) with low rectal anastomosis. Patients with a lower level of anastomosis had a statistically significantly greater number of stools, higher urgency and discrimination impairment, more pronounced solid, liquid and gas incontinence, and greater need for diapers (p<0.05 all). Therefore, patients with lower anastomosis had a statistically significant impairment of their quality of life and higher Wexner score (p<0.001 for both analyses). Our study results suggested reduced neorectal capacity to be the main pathophysiological factor for the development of postoperative anorectal function impairment.

Peritoneal perforation during transanal endoscopic microsurgery is not associated with significant short-term complications

BACKGROUND

In patients treated by transanal endoscopic microsurgery (TEM), breach of the peritoneal cavity is a feared intraoperative challenge. Our aim is to analyze predictors and short-term outcomes of patients with peritoneal perforation (TEM-P) when compared to similar patients with no peritoneal compromise (TEM-N).

METHODS

At St. Paul's Hospital, demographic, surgical, pathologic, and follow-up data for all patients treated by TEM is maintained in a prospectively populated database. A retrospective review was performed and two groups were established for comparison: TEM-P and TEM-N. Statistical analysis was performed using student's t or chi-squared test, where appropriate.

RESULTS

Of 619 patients treated by TEM between 2007 and 2016, 39 (6%) patients were in the TEM-P group and 580 (94%) in the TEM-N group. There were no differences between the groups in patient age, gender, histology, or tumor size. Patients who had peritoneal perforations had more proximal lesions (11 vs. 7 cm, p < 0.0001), anterior lesions (56 vs. 43%, p < 0.05), and longer operations (80 vs. 51 min, p < 0.005). While most defects were closed endoluminally, 2 patients with perforation were converted to transabdominal surgery. There was a difference in overall hospital stay with TEM-P patients staying on average 2 days in hospital with fewer patients managed as day surgery (31 vs. 73%, p < 0.0001). There were no mortalities or significant 30-day complications in the TEM-P group and only one patient required readmission.

CONCLUSIONS

The St. Paul's Hospital TEM experience suggests patients with peritoneal breach during TEM can be safely managed with outcomes similar to patients without peritoneal entry. Proximal, anterior lesions are at highest risk of peritoneal perforation.

Pitfalls in MRI of rectal cancer: What radiologists need to know and avoid

Preoperative staging of rectal cancer using magnetic resonance imaging (MRI) has become an important component of clinical management. Although MRI is the modality of choice for rectal cancer diagnosis and staging, there are certain inherent potential pitfalls that radiologists need to recognize in order to avoid imaging misinterpretation, including choice of MRI protocol; choice of MRI technique; potential mimickers of rectal cancer; mucinous rectal tumor; differentiation between extramural tumor invasion and desmoplastic reaction; differentiation between low rectal cancer and anal cancer; problems relating to nodal involvement, peritoneal reflection, and mesorectal fascia invasion; and, challenges associated with restaging, post-treatment changes, and complications. The aim of this article was to heighten radiologist awareness of these potential pitfalls in order to improve diagnosis, decision-making, and patient outcomes.

Recognition of Anterior Peritoneal Reflections and Their Relationship With Rectal Tumors Using Rectal Magnetic Resonance Imaging

Our goal was to explore the factors influencing the visualization of anterior peritoneal reflections (APRs) using rectal MRI. We evaluated the usefulness of rectal MRI in measuring the distance from the anal verge to the APR and determining the relationship between the APR and the rectal tumor. Clinical and imaging data from 319 patients who underwent surgery after MRI examination between October 2010 and December 2013 were retrospectively analyzed. The distance from the anal verge to the APR and the relationship between the APR and the location of the rectal tumor was evaluated. analysis of variance, logistic regression, independent samples t tests, and Kappa tests were used for statistical analysis. The APR was visible in 283 of 319 cases using rectal MRI. The APR was more readily observed in patients who were older than 58 years (P = 0.046), in patients whose subcutaneous fat thicknesses were >22.2 mm (P = 0.004), in patients with nondistended bladders (P = 0.001), and in those with an anteversion of the uterus (P = 0.001). There was a significant difference between the distance from the anal verge to the APR between females (10.4 ± 1.1 cm) and males (10.0 ± 1.2 cm; P = 0.014). The accuracy in predicting tumor location with respect to the APR was 70%, 50%, 98.2%, respectively for patients with tumors located above, at, and below the APR (compared with the location determined during surgery). Most of the APRs were visible using rectal MRI, whereas certain internal factors influence visualization. Rectal MRI could be a useful tool for evaluating the distance from the anal verge to the APR and relationship between rectal tumors and the APR.

Future directions for monitoring treatment response in colorectal cancer

Treatment of advanced colon and rectal cancer has significantly evolved with the introduction of neoadjuvant chemoradiation therapy so much that, along with more effective chemotherapy regimens, surgery has been considered unnecessary among some institutions for select patients. The tumor response to these treatments has also improved and ultimately has been shown to have a direct effect on prognosis. Yet, the best way to monitor that response, whether clinically, radiologically, or with laboratory findings, remains controversial. The authors' aim is to briefly review the options available and, more importantly, examine emerging and future options to assist in monitoring treatment response in cases of locally advanced rectal cancer and metastatic colon cancer.

Definition of the rectum and level of the peritoneal reflection - still a matter of debate?

Introduction

Pathological lesions of the rectum are common and their management requires detailed knowledge of pelvic anatomy. There has been considerable debate as to the definition of the rectum and the variability of the level of the peritoneal reflection. The lack of a clear consensus was proven in the research by McCullen et al. regarding the current pattern of practice for the investigation of primary rectal cancer by general surgeons.

Aim

To carry out bibliographic research on the definition of the rectum and level of the peritoneal reflection.

Material and methods

A web-based published literature search of PubMed, Ovid Medline, Science Direct and Springer was made.

Results

The paper presents the current definitions of proximal and distal margin of the rectum and level of peritoneal reflection based not only on the results of tests on cadavers but also on living humans.

Conclusions

The results of tests on living humans allow more accurate qualification of patients for local excision, which is particularly important for patients with colorectal cancer.

Recognition of the anterior peritoneal reflection at rectal MRI

OBJECTIVE

The purpose of this article is to assess radiologists' ability to identify the anterior peritoneal reflection on MRI.

CONCLUSION

The peritoneal reflection was identified on MRI by two radiologists in the majority of patients with rectal cancer.

Is rectal MRI beneficial for determining the location of rectal cancer with respect to the peritoneal reflection?

Background

An objective method for determining the location of the cancer with respect to peritoneal reflection would be helpful to decide the treatment modality for rectal cancer. This study was designed to evaluate the accuracy and usefulness of rectal MRI to determine spatial relations between the peritoneal reflection and rectal cancer and to compare these with operative findings.

Patients and methods

Patients that underwent a rectal cancer operation after a rectal MRI check between November 2008 and June 2010 were considered for the study. The patients that received preoperative concurrent chemoradiation or trans-anal local excision were excluded.

Results

Fifty-four patients constituted the study cohort. By comparing surgical and radiologic findings, the accuracy for predicting tumour location in relation to the peritoneal reflection by rectal MRI in all patients was 90.7%. In terms of tumour location in relation to peritoneal reflection, the accuracy of rectal MRI was 93.5% in patients with a tumour located above the peritoneal reflection, 90.0% in patients with a tumour located on the peritoneal reflection, and 84.6% in patients with a tumour located below the peritoneal reflection (p=0.061). When the cohort was subdivided by gender, body mass index (BMI), operative findings, or tumour size, no significant difference was observed among subgroups.

Conclusions

Rectal MRI could be a useful tool for evaluating the relation between rectal cancer and peritoneal reflection especially when tumour size is less than 8cm. Rectal MRI can provide information regarding the location of rectal cancer in relation to the peritoneal reflection for treatment planning purposes.

Endorectal ultrasound: its role in the diagnosis and treatment of rectal cancer

With development over the past 25 years of new surgical techniques and neoadjuvant therapy regimens for rectal cancer, physicians now have a range of treatment options that minimize morbidity and maximize the potential for cure. Accurate pretreatment staging is critical, ensuring adequate therapy and preventing overtreatment. Many options exist for staging primary rectal cancer. However, endorectal ultrasound (ERUS) remains the most attractive modality. It is an extension of the physical examination, and can be performed easily in the office. It is cost effective and is generally well tolerated by the patient, without need for general anesthesia. The authors discuss the data currently available on ERUS, including its accuracy and limitations, as well as the technical aspects of performing ERUS and interpreting the results. They also discuss new ultrasound technologies, which may improve rectal cancer staging in the future.

Intra-operative measurement of surgical lengths of the rectum and the peritoneal reflection in Korean

The lengths of the surgical rectum and peritoneal reflection were important factors in treatment modality of rectal tumor. To evaluate the surgical length of rectum, we measured the length of the peritoneal reflections, sacral promontory and termination of the taenia coli from the anal verge by rigid sigmoidoscope in 23 male and 23 females during operation. The mean lengths of the sacral promontory were 16.5+/- 2.2 cm and 16.1+/-2.2 cm in the males and females, respectively. As for the peritoneal reflection, the results were anterior (8.8+/-2.2 cm, 8.1+/-1.7 cm), lateral (10.8+/-2.7 cm, 11.4+/-1.9 cm) and posterior (13.8+/-2.5 cm, 14.0+/-1.9 cm), respectively. There were no statistically significant differences between male and female. And only height had a correlation with the length of sacral promontory both in male and female (p=0.015 and p=0.018, respectively). For all the estimated lengths, the length of the sacral promontory had a correlation with the lengths of the anterior (p<0.001 and p=0.001) and posterior (p<0.001 and p<0.001) peritoneal reflections in males and females, respectively. We suggest that the intra-operative lengths of the rectum and peritoneal reflection will be useful information for treatment modality of rectal tumor clinically in Korean.

Determination of the peritoneal reflection using intraoperative proctoscopy

PURPOSE

Rectal carcinomas are amenable to transanal excision in 3 to 5 percent of cases. Location below the peritoneal reflection is one requirement for transanal excision and transanal endoscopic microsurgery. The location of the peritoneal reflection has not been extensively studied in living patients.

METHODS

This study investigated the location of the peritoneal reflection in 50 patients undergoing laparotomy. The distance from the anal verge to the peritoneal reflection was measured in each patient via simultaneous intraoperative proctoscopy and intra-abdominal visualization of the peritoneal reflection. The mean distance to the peritoneal reflection, range of measurements, and complications of proctoscopy were recorded.

RESULTS

Intraoperative proctoscopy was performed on 50 patients after informed consent. The mean lengths of the peritoneal reflection were 9 cm anteriorly, 12.2 cm laterally, and 14.8 cm posteriorly for females, and 9.7 cm anteriorly, 12.8 cm laterally, and 15.5 cm posteriorly for males. The lengths of the anterior, lateral, and posterior peritoneal measurements were statistically different from one another, regardless of gender (P < 0.01). There were no complications of proctoscopy.

CONCLUSIONS

Our data indicated that the peritoneal reflection is located higher on the rectum than reported in autopsy studies, and that there is no difference between males and females. Knowledge of the location and position of a rectal carcinoma in relationship to the peritoneal reflection will help the surgeon optimize the use of transanal techniques of resection.