Comparison between magnetic resonance imaging and rigid rectoscopy in the preoperative identification of intra- and extraperitoneal rectal cancer

Defining the tumor location in rectal cancer - Practice variations and impact on treatment decision making

OBJECTIVE

To summarize differences in current guideline recommendations for rectal tumor localization and generate an overview of published MRI measurement methods and their correlation with endoscopy.

SUMMARYOF BACKGROUND DATA

Rectal tumor location is a well-known factor that impacts treatment planning, but there is currently no consensus on the optimal method to define it.

METHODS

A literature search was conducted to retrieve clinical and radiological rectal cancer guidelines as well as original research studies on MRI-based measurements. Guidelines were assessed for definitions, landmarks, modalities and measurement methods to define tumor location, and how these impact treatment planning. Research studies were evaluated to compare MRI-methods and their correlation with endoscopy.

RESULTS

18 clinical and 6 radiological guidelines were retrieved. In 83 % of clinical guidelines tumor location (low/middle/high) is included in the treatment algorithm as a factor impacting surgical and/or neoadjuvant treatment. Measurement cut-offs and landmarks vary significantly with the anal verge being the most commonly used landmark (28 %). Thirty-nine percent of clinical guidelines offer no definitions to define rectal tumor location. The majority of research studies (67 %) reported good-excellent agreement between MRI and endoscopy, though measurement differences of up to 2.5 cm were reported.

CONCLUSION

There is substantial variation in definitions and landmarks recommended in current guidelines to measure and classify rectal tumor location. This may affect treatment planning as well as trial inclusions, highlighting the need for standardized methods that better align between clinical and radiological guidelines.

Diagnostic accuracy of endoscopy in determining rectal tumor proximity to the peritoneal reflection

PURPOSE

Treatment of invasive rectal adenocarcinoma is stratified into upfront surgery versus neoadjuvant chemoradiotherapy, in part, based on tumor distance from the anal verge (AV). This study examines the correlation between tumor distance measurements (endoscopic and MRI) and relationship to the anterior peritoneal reflection (aPR) on MRI.

METHODS

A single-center retrospective study was performed at a tertiary center accredited by the National Accreditation Program for Rectal Cancer (NAPRC). 162 patients with invasive rectal cancer were seen between October of 2018 and April of 2022. Sensitivity and specificity were determined for MRI and endoscopic measurements in their ability to predict tumor location relative to the aPR.

RESULTS

One hundred nineteen patients had tumors endoscopically and radiographically measured from the AV. Pelvic MRI characterized tumors as above (intraperitoneal) or at/straddles/below the aPR (extraperitoneal). True positives were defined as extraperitoneal tumors [Formula: see text] 10 cm. True negatives were defined as intraperitoneal tumors > 10 cm. Endoscopy was 81.9% sensitive and 64.3% specific in predicting tumor location with respect to the aPR. MRI was 86.7% sensitive and 92.9% specific. Utilizing a 12 cm cutoff, sensitivity of both modalities increased (94.3%, 91.4%) but specificity decreased (50%, 64.3%).

CONCLUSION

For locally invasive rectal cancers, tumor position relative to the aPR is an important factor in determining the role of neoadjuvant therapy. These results suggest endoscopic tumor measurements do not accurately predict tumor location relative to the aPR, and may lead to incorrect treatment stratification recommendation. When the aPR is not identified, MRI-reported tumor distance may be a better predictor of this relationship.

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.

How do they measure up: Assessing the height of rectal cancer with digital rectal exam, endoscopy, and MRI,

Background

Outcomes in rectal cancer are dependent on tumor height. Modalities for assessing tumor height include MRI, endoscopy, and digital rectal exam (DRE). We seek to identify correlations between these modalities.

Methods

Retrospective analysis of 120 rectal cancer patients at a single institution. Correlation coefficients and distance of the tumor to anal verge between MRI, endoscopy, and DRE were compared by region.

Results

The distances of tumor (cm) from anal verge were: MRI: 6.2 ± 3.0, endoscopy: 5.9 ± 2.9, DRE: 5.4 ± 2.4 (p = 0.238). Endoscopy and DRE strongly correlated with MRI (spearman coefficient 0.899 and 0.842, respectively). Endoscopy and DRE also strongly correlated (spearman coefficient 0.876). Correlation coefficients were highest in the middle rectum, weak in the low rectum, and non-correlated in the upper rectum.

Conclusions

MRI, endoscopy, and DRE strongly correlated overall. DRE demonstrated the lowest average distance. Correlations differed by region, suggesting high or low rectal tumors are difficult to characterize.

Measuring Rectal Cancer Tumor Height: Concordance Between Clinical Examination and MRI

BACKGROUND

Rectal cancer is categorized into categories on the basis of tumor height measurements. Tumor height is used to guide initial treatment and determines the eligibility for clinical trials.

OBJECTIVE

This study aimed to determine the concordance between tumor heights measured by MRI and by clinical examination.

DESIGN

This was an institutional review board-approved retrospective analysis of MRI and the clinical measurements of tumor height.

SETTING

This study was conducted at a single university center that was accredited by the Commission on Cancer National Accreditation Program for Rectal Cancer.

PATIENTS

Ninety-five patients who were treated between 2015 and 2019 and who had an MRI and clinical evaluation were included.

MAIN OUTCOME MEASUREMENTS

The mean difference of tumor height between MRI and clinical examination was calculated. Secondary outcomes were to assess whether position in the rectum, age, BMI, or sex would affect the difference and how the measurements would change eligibility for rectal cancer trials.

RESULTS

Tumor height measurement by MRI and clinical examination had a good correlation, with r = 0.89 and p < 0.001. The mean absolute difference of measurement of tumor height was 1.56 cm. Higher tumors had a larger absolute difference between measurements. Body mass index was significantly associated with the difference in measurements. The discordance in measurements led to a change in eligibility for clinical trials for 38.9% of patients. Clinical trial eligibility was not significantly associated with tumor height category, sex, or patient age.

LIMITATIONS

This study was conducted at a single center with retrospective methodology.

CONCLUSIONS

Although MRI and clinical measurements showed a strong correlation, nearly 40% of our patients had a change in clinical trial eligibility depending on measurement modality. We suggest that trial investigators be consistent in establishing measurement technique as their inclusion criterion. See Video Abstract at http://links.lww.com/DCR/B756.

MEDICIN DE LA ALTURA DEL TUMOR DE CNCER DE RECTO CONCORDANCIA ENTRE EL EXAMEN CLNICO Y LA RESONANCIA MAGNTICA

ANTECEDENTES:El cáncer de recto se clasifica en categorías basadas en las mediciones de la altura del tumor. La altura del tumor se usa para guiar el tratamiento inicial y determina la elegibilidad para los ensayos clínicos.OBJETIVO:Determinar la concordancia entre la altura de los tumores medida por resonancia magnética (RMN) y por examen clínico.DISEÑO:Este fue un análisis retrospectivo aprobado por el IRB de la resonancia magnética y las mediciones clínicas de la altura del tumor.AJUSTE:Esto se llevó a cabo en un único centro universitario que fue acreditado por el Programa Nacional de Acreditación del Cáncer de Recto de la Comisión de Cáncer.PACIENTE:Se incluyeron 95 pacientes que fueron atendidos entre 2015 y 2019 y que tuvieron una resonancia magnética y evaluación clínica.PRINCIPALES MEDIDAS DE RESULTADOS:Se calculó la diferencia media de la altura del tumor entre la resonancia magnética y el examen clínico. Los resultados secundarios fueron evaluar si la posición en el recto, la edad, el índice de masa corporal (IMC) o el sexo afectarían la diferencia y cómo las mediciones cambiarían la elegibilidad para los ensayos de cáncer de recto.RESULTADOS:La medición de la altura del tumor por resonancia magnética y el examen clínico tuvo una buena correlación con r = 0,89 y p < 0,001. La diferencia absoluta media de medición de la altura del tumor fue de 1,56 cm. Los tumores más altos tenían una diferencia absoluta más grande entre las mediciones. El IMC se asoció significativamente con la diferencia en las mediciones. La discordancia en las mediciones llevó a un cambio en la elegibilidad para los ensayos clínicos para el 38,9% de los pacientes. La elegibilidad para ensayos clínicos no se asoció significativamente con la categoría de altura del tumor, el sexo o la edad del paciente.LIMITACIONES:Se realizó en un solo centro con metodología retrospectiva.CONCLUSIONES:Aunque la resonancia magnética y las mediciones clínicas mostraron una fuerte correlación, casi el 40% de nuestros pacientes tuvieron un cambio en la elegibilidad para los ensayos clínicos según la modalidad de medición. Sugerimos que los investigadores del ensayo sean coherentes al establecer la técnica de medición como criterio de inclusión. Consulte Video Resumen en http://links.lww.com/DCR/B756.

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.

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.

Rapid Initiation of Neoadjuvant Chemoradiotherapy After Diagnosis is Associated With Improved Pathologic Response in Locally Advanced Rectal Cancer

INTRODUCTION

In rectal cancer, neoadjuvant chemoradiation (NCRT) is preferred because of toxicity profile, improved resectability and sphincter preservation, although with no impact on overall survival. Pathologic complete response (pCR) to NCRT has been linked with longer disease-free survival (DFS). The study purpose was to evaluate an association between clinical factors and treatment schedule with tumor response and treatment outcome, among patients with locally advanced rectal cancer.

PATIENTS AND METHODS

In this single-center retrospective study, conducted over 9 years (2011 to 2020), patients with stage II to III rectal cancer who had received NCRT were enrolled. The standard radiotherapy was 45 Gy to the pelvis, with a simultaneous integrated 50 Gy boost to the primary tumor. Continuous 5-Fluorouracil or oral capecitabine was administered concurrently. Surgery was preplanned within 6 to 8 weeks. Multinomial logistic regressions for evaluation of clinical factors, Kaplan-Meier method for DFS estimation, and receiver operating characteristic analysis for determination of the optimal timeframe were used.

RESULTS

Of 279 cases, pCR was observed in 72 (25.8%). In 207 cases, pTis-4N-negative was obtained in 137 (66.2%), pT0N-positive in 6 (2.9%), and pTis-4N-positive in 64 (30.9%). The pCR group had shorter diagnosis-NCRT time (P<0.01) and on-treatment time (P=0.05). DFS was longer for pCR and partial responders with clinical stage II and III (P<0.0001). Diagnosis-NCRT time was shown different between pCR and non-pCR groups. receiver operating characteristic analysis (P<0.01) showed that a diagnosis-NCRT time of <4.5 weeks predicts pCR with a sensitivity of 88% and specificity of 81% accuracy.

CONCLUSION

The time elapsed between rectal cancer diagnosis and NCRT initiation is significantly associated with pCR. Reducing this time may increase the probability of achieving pCR.

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.

How to accurately measure the distance from the anal verge to rectal cancer on MRI: a prospective study using anal verge markers

PURPOSE

To determine an accurate method for localizing rectal cancer using the distance from the anal verge on preoperative MRI.

METHODS

This prospective study included 50 patients scheduled for MRI evaluation of rectal cancer. After rectal filling with gel, MRI was performed with two markers attached at the anal verge. The distance between the tumor and the anal verge on a sagittal T2-weighted image (T2WI) was measured independently by two radiologists using six methods divided into three groups of similar measurement approaches, and compared to those obtained on rigid sigmoidoscopy. The anal verge location relative to the external anal sphincter was assessed on oblique coronal T2WI in reference to the markers. Correlation analysis was performed using the intraclass correlation coefficient (ICC) for verification, and a paired t test was used to evaluate the mean differences.

RESULTS

The highest correlation (ICC 0.797-0.815) and the least mean difference (0.74-0.85 cm) with rigid sigmoidoscopy, and the least standard deviation (3.12-3.17 cm) were obtained in the direct methods group using a straight line from the anal verge to the tumor. The anal verge was localized within a range of - 1.4 to 1.5 cm (mean - 0.31 cm and - 0.22 cm) from the lower end of the external anal sphincter.

CONCLUSION

The direct methods group provided the most accurate tumor distance among the groups. Among the direct methods, we recommend the direct mass method for its simplicity. Despite minor differences in location, the lower end of the external anal sphincter was a reliable anatomical landmark for the anal verge.

Comparison of MRI and colonoscopy in determining tumor height in rectal cancer

Background and aim

Endoscopy and magnetic resonance imaging (MRI) are used routinely in the diagnostic and preoperative work-up of rectal cancer. We aimed to compare colonoscopy and MRI in determining rectal tumor height.

Methods

Between 2002 and 2012, all patients with rectal cancer with available MRIs and endoscopy reports were included. All MRIs were reassessed for tumor height by two abdominal radiologists. To obtain insight in techniques used for endoscopic determination of tumor height, a survey among regional endoscopists was conducted.

Results

A total of 211 patients with rectal cancer were included. Tumor height was significantly lower when assessed by MRI than by endoscopy with a mean difference of 2.5 cm (95% CI: 2.1-2.8). Although the agreement between tumor height as measured by MRI and endoscopy was good (intraclass correlation coefficient (ICC) 0.7 (95% CI: 0.7-0.8)), the 95% limits of agreement varied from -3.0 cm to 8.0 cm. In 45 patients (21.3%), tumors were regarded as low by MRI and middle-high by endoscopy. MRI inter- and intraobserver agreements were excellent with an ICC of 0.8 (95% CI: 0.7-0.9) and 0.9 (95% CI: 0.9-1.0), respectively. The survey showed no consensus among endoscopists as to how to technically measure tumor height.

Conclusion

This study showed large variability in rectal tumor height as measured by colonoscopy and MRI. Since MRI measurements showed excellent inter- and intraobserver agreement, we suggest using tumor height measurement by MRI for diagnostic purposes and treatment allocation.

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.