Effects of magnetic resonance imaging (MRI)-detected extramural vascular invasion (mrEMVI) and tumor deposits (TDs) on distant metastasis and long-term survival after surgery for stage III rectal cancer: a retrospective study grouped based on the relationship between the bottom of the tumor and peritoneal reflection.

Background: To evaluate the effect of magnetic resonance imaging (MRI)-detected extramural vascular invasion (mrEMVI) and tumor deposits (TDs) on distant metastasis and long-term survival after surgery for stage III rectal cancer based on the relationship between the bottom of the tumor and peritoneal reflection. Methods: A retrospective study was performed on 694 patients who underwent radical resection for rectal cancer at the Harbin Medical University Tumor Hospital from October 2016 to October 2021. According to the surgical records, a new group was established based on the relationship between the lower end of the tumor and peritoneal reflection. On the peritoneal reflection group: the tumors are all located on the peritoneal reflection. Across the peritoneal reflection group: the tumors recurred across the peritoneal reflection. Under the peritoneal reflection group: the tumors are all located under the peritoneal reflection. We evaluated the effects of mrEMVI and TDs on postoperative distant metastasis and long-term survival of stage III rectal cancer by combining mrEMVI with TDs. Results: In the whole study population, neoadjuvant therapy (P=0.003) was negatively correlated with distant metastasis after rectal cancer surgery. Also, mesorectal fascia (MRF) (P=0.024), postoperative distant metastasis (P<0.001), and TDs (P<0.001) were independent risk factors for long-term survival after rectal cancer surgery. Lymph node metastasis (P<0.001) and neoadjuvant therapy (P=0.023) were independent risk factors for the presence or absence of TDs of rectal cancer. In the non-neoassisted subgroup, postoperative distant metastasis (P<0.001) was considered to be an independent risk factor for long-term survival after rectal cancer surgery. Conclusions: In the under the peritoneal reflection group, the combination of mrEMVI and TDs seems to play a certain guiding role in predicting distant metastasis and long-term survival after rectal cancer surgery.

Determination of the positional relationship of the second Houston valve and peritoneal reflection using computed tomographic colonography and magnetic resonance imaging.

PURPOSE: The second Houston valve is used as a surrogate for estimating the position of the peritoneal reflection; however, the concordance between the positions of the valve and peritoneal reflection has not been investigated. This study aimed to clarify this positional relationship. METHODS: The second Houston valve and peritoneal reflection positions were assessed using tomographic colonography and magnetic resonance imaging. In total, 117 patients were enrolled in this study. RESULTS: The positions of the second Houston valve and peritoneal reflection were nearly concordant, although the space between them ranged from - 20.7 to 33.9 mm. A peritoneal reflection located further from the anal verge than the second Houston valve was defined as a shallow peritoneal reflection. Male sex, high body weight, and a high body mass index were significantly correlated with a shallower peritoneal reflection, as determined by a univariate analysis (sex: P = 0.0138, weight: P = 0.0097, body mass index: P = 0.0311). A multivariate analysis revealed a significantly shallower peritoneal reflection in males than in females (odds ratio: 2.75, 95% confidence interval: 1.15-6.56, P = 0.023). CONCLUSIONS: The second Houston valve located near the peritoneal reflection can be a useful surrogate marker for estimating its position. In relatively heavy males, the peritoneal reflection is located more cranially than the second Houston valve.

Case report: Gross persistent rectal prolapse. A case treated without mesh using deep retrorectal dissection/suturing.

A previously well 15-year-old male presented with a history of gross rectal prolapse (GRP) involving full-thickness rectal prolapse of increasing severity and incidence over 6 months that occurred with every bowel motion, varying from 10 to 40 cm. He denied constipation and passed a soft motion once daily, adeptly reducing his prolapsed rectum after each motion. This case illustrates technical challenges and planning for surgical intervention for optimal treatment in keeping with an FDA alert issued April, 2019 banning surgical mesh for pelvic organ prolapse. Preoperative fluoroscopic defecography confirmed rectal prolapse beginning with eversion of the anal verge identified on inspection. For surgery, general anesthesia was induced, he was placed in a Trendelenburg position, and four ports were inserted. The peritoneum was incised and blunt dissection used to expose the levator ani complex (LAC) taking care to prevent lateral nerve injury and preserve regional vascularity. Seven polypropylene sutures were used to fix the seromuscular posterior wall of the rectum to the median raphe of the LAC, the presacral fascia, and the periosteum of the sacral promontory. Operative time was 170 min. Postoperative recovery and progress were unremarkable. Currently, 5 years postoperatively, defecation is regular without recurrence of prolapse. For prolapse involving protrusion of the upper rectum without eversion of the anal verge, rectal fixation to the sacral promontory without further dissection beyond the peritoneal reflection is adequate, but when extensive prolapse is associated with eversion of the anal verge, more extensive blunt dissection from the peritoneal reflection to the LAC with multiple rectopexy sutures is valid for reducing risks for recurrence and eliminating mesh-related complications.

Cáncer de recto a nivel de la reflexión peritoneal. Exactitud de la RM preoperatoria y correlación anatomopatológica. Estudio prospectivo / Rectal cancer at the peritoneal reflection. Preoperative MRI accuracy and histophatologic correlation. Prospective study

Introducción Establecer la exactitud de la resonancia magnética (RM) para determinar la localización de los tumores rectales en relación con la reflexión peritoneal (RP) y su potencial afectación. Métodos Estudio prospectivo de 161 pacientes intervenidos por cáncer de recto. Las piezas quirúrgicas han sido analizadas mediante un método de doble tinción, superficie serosa con colorante naranja y grasa mesorrectal con tinta china, para comparar los resultados con la RM preoperatoria. Resultados Veintidós tumores se localizaron por encima, 65 a nivel y 74 por debajo de la RP. La RM clasificó la localización del tumor respecto a la RP de manera correcta en el 90,6% y fue capaz de detectar el 80,5% de los casos con infiltración de la RP. La RM presentó una exactitud del 92,5% para clasificar el tumor como intra o extraperitoneal. El 28,7% de los tumores por encima y a nivel de la RP presentaba anatomopatológicamente infiltración de la serosa peritoneal. Conclusiones La RM es una prueba precisa para determinar la localización de los tumores de recto en relación con la RP y su posible afectación. En el tallado macroscópico, el método de doble colorante es eficaz para determinar la afectación serosa (pT4a) y diferenciarla de la fascia mesorrectal (AU)

Introduction To investigate magnetic resonance imaging (MRI) accuracy for determining the location of rectal tumors with respect to the peritoneal reflection (PR) and its potential involvement Methods Prospective study of 161 patients ongoing surgery for rectal cancer. A double-ink method has been aplied to examine surgical specimen, orange ink for the serosal surface and indian ink for the mesorrectal margin, and assess preoperative MRI accuracy. Results Twenty-two tumors were located above, 65 at and 74 below PR. MRI accuracy was 90.6% for determining tumor's location with respect to the PR and 80.5% for defining peritoneal involvement. For classifying tumors according to their intra or extraperitoneal location an accuracy of 92.5% was set for MRI. Histophatologic peritoneal involvement was found in 28.7% of tumors located above or at the PR. Conclusions Magnetic resonance imaging accurately predicts the location of rectal tumors with respect to the PR and its potential involvement. The double-ink method is useful to assess serosal involvement (pT4a) and to distinguish mesorrectal fascia from the peritonealized surface (AU)

Is there a precise correlation between the lengths of the peritoneal reflection and the middle rectal valve?

Introduction: Pelvic anatomy remains a challenge, and thorough knowledge of its intricate landmarks has major clinical and surgical implications in several medical specialties. The peritoneal reflection is an important landmark in intraluminal surgery, rectal trauma, impalement, and rectal adenocarcinoma. Objectives: To investigate the correlation between the lengths of the middle rectal valve and of the peritoneal reflection determined with rigid sigmoidoscopy and to determine whether there are any differences in the location of the peritoneal reflection between the genders and in relation to body mass index (BMI) and parity. Design: We prospectively investigated the location of the middle rectal valve and of the peritoneal reflection via intraoperative rigid sigmoidoscopy in colorectal cancer patients undergoing elective colorectal surgery. Results: We evaluated 38 patients with a mean age of 55.5 years old (57.5% males) who underwent colorectal surgery at the coloproctology service of the Hospital Santa Marcelina, São Paulo, state of São Paulo, Brazil. There was substantial agreement between the lengths of the middle rectal valve and of the peritoneal reflection (Kappa = 0.66). In addition, the peritoneal reflection was significantly lower in overweight patients (p = 0.013 for women and p < 0.005 for men) and in women with > 2 vaginal deliveries (p = 0.009), but there was no significant difference in the length of the peritoneal reflection between genders (p = 0.32). Conclusion: There was substantial agreement between the lengths of the peritoneal reflection and of the middle rectal valve, and the peritoneal reflection was significantly lower in overweight patients and in women with more than two vaginal deliveries. (AU)

Rectal cancer at the peritoneal reflection. Preoperative MRI accuracy and histophatologic correlation. Prospective study.

INTRODUCTION: To investigate magnetic resonance imaging (MRI) accuracy for determining the location of rectal tumors with respect to the peritoneal reflection (PR) and its potential involvement. METHODS: Prospective study of 161 patients ongoing surgery for rectal cancer. A double-ink method has been aplied to examine surgical specimen, orange ink for the serosal surface and indian ink for the mesorrectal margin, and assess preoperative MRI accuracy. RESULTS: Twenty-two tumors were located above, 65 at and 74 below PR. MRI accuracy was 90.6% for determining tumor's location with respect to the PR and 80.5% for defining peritoneal involvement. For classifying tumors according to their intra or extraperitoneal location an accuracy of 92.5% was set for MRI. Histophatologic peritoneal involvement was found in 28.7% of tumors located above or at the PR. CONCLUSIONS: Magnetic resonance imaging accurately predicts the location of rectal tumors with respect to the PR and its potential involvement. The double-ink method is useful to assess serosal involvement (pT4a) and to distinguish mesorrectal fascia from the peritonealized surface.

Accuracy of MRI for predicting anterior peritoneal reflection involvement in locally advanced rectal cancer: a comparison with operative findings.

PURPOSE: To assess the diagnostic accuracy of preoperative rectal MRI for anterior peritoneal reflection (APR) involvement in rectal cancer through comparison with the surgeon's operative findings. METHODS: This retrospective study was approved by the institutional review board; informed consent was waived. We enrolled 55 consecutive patients with suspected locally advanced mid-to-upper rectal cancer. All patients underwent rectal MRI using a 3T system. APR involvement in rectal cancer was assessed radiologically using a 5-point scale by two independent board-certified abdominal radiologists. The surgeon's evaluation during surgery was regarded as the gold standard for APR involvement. The accuracy of rectal MRI in predicting APR involvement was obtained. RESULTS: Rectal MRI showed good APR identification (rater 1, 92.7%; rater 2, 94.7%). On preoperative rectal MRI, rater 1 diagnosed 19 (34.5%) patients as having APR involvement and rater 2 diagnosed 28 (50.9%) as having APR involvement. There was moderate agreement (κ = 0.602, p < 0.001) between the two raters with regard to the evaluation of APR involvement. During surgery, the surgeon confirmed APR involvement in 13 (23.6%) patients. The sensitivity, specificity, PPV, and NPV of preoperative MRI for APR involvement were 69.2%, 76.2%, 47.4%, and 88.9%, respectively. The diagnostic accuracy of MRI for predicting APR involvement was 74.6%. CONCLUSION: Preoperative rectal MRI provides accurate anatomical information regarding APR involvement with high conspicuity. However, MRI has relatively low sensitivity (< 70%) and a low PPV (< 50%) with regard to the assessment of APR involvement in rectal tumors. Both rater 1 and rater 2 evaluated these images as positive involvement of APR. The patient underwent laparoscopic low anterior resection after preoperative evaluation. However, during surgery, the surgeon evaluated APR involvement as negative, and the final pathologic staging was confirmed as T3.

Rectal cancer at the peritoneal reflection. Preoperative MRI accuracy and histophatologic correlation. Prospective study. / Cáncer de recto a nivel de la reflexión peritoneal. Exactitud de la RM preoperatoria y correlación anatomopatológica. Estudio prospectivo.

INTRODUCTION: To investigate magnetic resonance imaging (MRI) accuracy for determining the location of rectal tumors with respect to the peritoneal reflection (PR) and its potential involvement. METHODS: Prospective study of 161 patients ongoing surgery for rectal cancer. A double-ink method has been aplied to examine surgical specimen, orange ink for the serosal surface and indian ink for the mesorrectal margin, and assess preoperative MRI accuracy. RESULTS: Twenty-two tumors were located above, 65 at and 74 below PR. MRI accuracy was 90.6% for determining tumor's location with respect to the PR and 80.5% for defining peritoneal involvement. For classifying tumors according to their intra or extraperitoneal location an accuracy of 92.5% was set for MRI. Histophatologic peritoneal involvement was found in 28.7% of tumors located above or at the PR. CONCLUSIONS: Magnetic resonance imaging accurately predicts the location of rectal tumors with respect to the PR and its potential involvement. The double-ink method is useful to assess serosal involvement (pT4a) and to distinguish mesorrectal fascia from the peritonealized surface.

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.

Which Definition of Upper Rectal Cancer Is Optimal in Selecting Stage II or III Rectal Cancer Patients to Avoid Postoperative Adjuvant Radiation?

BACKGROUND: In most guidelines, upper rectal cancers (URC) are not recommended to take neoadjuvant or adjuvant radiation. However, the definitions of URC vary greatly. Five definitions had been commonly used to define URC: 1) >10 cm from the anal verge by MRI; 2) >12 cm from the anal verge by MRI; 3) >10 cm from the anal verge by colonoscopy; 4) >12 cm from the anal verge by colonoscopy; 5) above the anterior peritoneal reflection (APR). We hypothesized that the fifth definition is optimal to identify patients with rectal cancer to avoid adjuvant radiation. METHODS: The data of stage II/III rectal cancer patients who underwent radical surgery without preoperative chemoradiotherapy were retrospectively reviewed. The height of the APR was measured, and compared with the tumor height measured by digital rectal examination (DRE), MRI and colonoscopy. The five definitions were compared in terms of prediction of local recurrence, survival, and percentages of patients requiring radiation. RESULTS: A total of 576 patients were included, with the intraoperative location of 222 and 354 tumors being above and straddle/below the APR, respectively. The median distance of the APR from anal verge (height of APR) as measured by MRI was 8.7 (range: 4.5-14.3) cm. The height of APR positively correlated with body height (r=0.862, P<0.001). The accuracy of the MRI in determining the tumor location with respect to the APR was 92.1%. Rectal cancer above the APR had a significantly lower incidence of local recurrence than those straddle/below the APR (P=0.042). For those above the APR, there was no significant difference in local recurrence between the radiation and no-radiation group. Multivariate analyses showed that tumor location regarding APR was an independent risk factor for LRFS. Tumor height as measured by DRE, MRI and colonoscopy were not related with survival outcomes. Fewer rectal cancer patients required adjuvant radiation using the definition by the APR, compared with other four definitions based on a numerical tumor height measured by MRI and colonoscopy. CONCLUSIONS: The definition of URC as rectal tumor above the APR, might be the optimal definition to select patients with stage II/III rectal cancer to avoid postoperative adjuvant radiation.

Comparison of computed tomography and magnetic resonance imaging in the discrimination of intraperitoneal and extraperitoneal rectal cancer: initial experience.

OBJECTIVES: To compare computed tomography (CT) and magnetic resonance imaging (MRI) in evaluation of intraperitoneal/extraperitoneal location of rectal cancers. METHODS AND MATERIALS: We assessed the identification of the anterior peritoneal reflection (APR) and the distance from the inferior edge of tumors to the anal verge and from the APR to the anal verge. RESULTS: Distances obtained with CT and MRI showed a strong correlation [Spearman's coefficient of rank correlation (rho): 0.995; P<.0001]. Magnetic resonance showed sensitivity of 100% (95% CI: 89.62-100.00%), specificity of 75% (95% CI: 20.34-95.88%), positive predictive value (PPV) of 97.14% (95% CI: 85.03-99.52%), and negative predictive value (NPV) of 100% (95% CI: 30.48-100.00%). CT showed a sensitivity of 100% (95% CI: 89.32-100.00%), specificity of 60% (95% CI: 15.40-93.51%), PPV of 94.29% (95% CI: 80.81-99.13%), and NPV of 100% (95% CI: 30.48-100.00%). CONCLUSIONS: CT demonstrated a potential supporting role in the evaluation of rectal cancer, showing a strong correlation with MRI.

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.

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.

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.

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.