Accuracy of endoscopic ultrasound in staging and restaging patients with locally advanced rectal cancer undergoing neoadjuvant chemoradiation

A model based on endorectal ultrasonography predicts lateral lymph node metastasis in low and middle rectal cancer

PURPOSE

To investigate the risk factors for lymph node (LN) metastasis in low and middle rectal tumors, construct a predictive model and test the model's diagnostic efficacy.

METHODS

The clinical and pathological data of 172 patients with rectal cancer confirmed by surgery were retrospectively evaluated, among whom 61 patients were finally included in this study. Patients were divided into positive groups and negative groups based on LN metastasis, and risk factors that might affect LN metastasis were analyzed. Finally, a risk predictive model was constructed based on the weights of each risk factor.

RESULTS

Compared with pathology, the efficacy of diagnosing LN metastasis only according to conventional endorectal ultrasonography (ERUS) features of LN was not high, with sensitivity 67%, specificity 86%, positive predictive value 76%, negative predictive value 80%, and accuracy 79%. Univariate analysis showed that circumferential angle of the tumor, ultrasonic T- stage (UT stage), conventional ultrasound features diagnosis of LN metastasis, strain ratio (SR) of tumor were risk factors for LN metastasis, while vascular resistance index of rectal tumor was protective factor. Multivariate analysis showed that UT stage (OR = 7.188, p = 0.049), conventional ultrasound features diagnosis of LN metastasis (OR = 8.010, p = 0.025) and SR (OR = 5.022, p = 0.031) were independent risk factors for LN metastasis. These risk factors were included in logistic regression analysis and the model was established, Y = -7.3 + 1.9 X10 + 2.1 X11 + 1.6 X13 (Y = Logit[P], P: LN metastasis rate, X10: UT stage, X11: conventional ultrasound features diagnosis of LN metastasis, X13: SR). The receiver operating characteristic (ROC) curve was used to test the model's predictive efficacy, the area under the curve was 0.95, sensitivity: 95%, specificity: 87%. Hosmer-Lemeshow goodness of fit test showed X2 = 6.015, p = 0.65 (p > 0.05), indicating that the model had a high predictive value.

CONCLUSION

Evaluation of perirectal LN metastasis only based on conventional ERUS features of LN was not effective enough. UT stage of tumor, conventional ultrasound features diagnosis of LN metastasis and SR were independent risk factors for LN metastasis. The predictive model had good assessment efficacy and had certain clinical application value.

Watch and wait approach in rectal cancer: Current controversies and future directions

According to the main international clinical guidelines, the recommended treatment for locally-advanced rectal cancer is neoadjuvant chemoradiotherapy followed by surgery. However, doubts have been raised about the appropriate definition of clinical complete response (cCR) after neoadjuvant therapy and the role of surgery in patients who achieve a cCR. Surgical resection is associated with significant morbidity and decreased quality of life (QoL), which is especially relevant given the favourable prognosis in this patient subset. Accordingly, there has been a growing interest in alternative approaches with less morbidity, including the organ-preserving watch and wait strategy, in which surgery is omitted in patients who have achieved a cCR. These patients are managed with a specific follow-up protocol to ensure adequate cancer control, including the early identification of recurrent disease. However, there are several open questions about this strategy, including patient selection, the clinical and radiological criteria to accurately determine cCR, the duration of neoadjuvant treatment, the role of dose intensification (chemotherapy and/or radiotherapy), optimal follow-up protocols, and the future perspectives of this approach. In the present review, we summarize the available evidence on the watch and wait strategy in this clinical scenario, including ongoing clinical trials, QoL in these patients, and the controversies surrounding this treatment approach.

Accuracy of endoscopic ultrasound in rectal cancer and its use in transanal endoscopic microsurgery

Introduction: This study evaluated the accuracy of endoscopic ultrasound (EUS) for preoperative staging of rectal cancer and guiding the treatment of transanal endoscopic microsurgery (TEM) in early rectal cancer.Material and methods: One-hundred-twenty-six patients with rectal cancer were staged preoperatively using EUS and the results were compared with postoperative histopathology results. Radical surgeries, including low anterior resection (LAR), abdominal-perineal resection (APR) and Hartmann surgeries, were performed on patients with advanced rectal cancers, and TEM was performed on patients with stage T1. The Kappa statistic was used to determine agreement between EUS-based staging and pathology staging.Results: The overall accuracies of EUS for T and N stage were 90.8% (Kappa = 0.709) and 76.7% (Kappa = 0.419), respectively. The accuracies of EUS for uT1, uT2, uT3, and uT4 stages were 96.8%, 92.1%, 84.1%, and 88.9%, respectively, and for uN0, uN1, and uN2 stages, they were 71.9%, 64.9%, and 93.0%, respectively. Twelve patients underwent TEM and received confirmed pathology results of early rectal cancer. After postoperative follow-up, there were no local recurrences or distant metastases.Conclusion: EUS is a good and comparable technique for postoperative staging of rectal cancer. Moreover, EUS is used as indicator for preoperative staging and tumor assessment strategy when considering TEM.

EFSUMB Recommendations for Gastrointestinal Ultrasound Part 3: Endorectal, Endoanal and Perineal Ultrasound

This article represents part 3 of the EFSUMB Recommendations and Guidelines for Gastrointestinal Ultrasound (GIUS). It provides an overview of the examination techniques recommended by experts in the field of endorectal/endoanal ultrasound (ERUS/EAUS), as well as perineal ultrasound (PNUS). The most important indications are rectal tumors and inflammatory diseases like fistula and abscesses in patients with or without inflammatory bowel disease (IBD). PNUS sometimes is more flexible and convenient compared to ERUS. However, the technique of ERUS is quite well established, especially for the staging of rectal cancer. EAUS also gained ground in the evaluation of perianal diseases like fistulas, abscesses and incontinence. For the staging of perirectal tumors, the use of PNUS in addition to conventional ERUS could be recommended. For the staging of anal carcinomas, PNUS can be a good option because of the higher resolution. Both ERUS and PNUS are considered excellent guidance methods for invasive interventions, such as the drainage of fluids or targeted biopsy of tissue lesions. For abscess detection and evaluation, contrast-enhanced ultrasound (CEUS) also helps in therapy planning.

Has the role of EUS in rectal cancer staging changed in the last decade?

The need for effective diagnosis, staging, and treatment of rectal cancer cannot be overstated. Accurate staging of rectal cancer has wide-ranging implications, including therapeutic strategy and prognosis. A change in stage may lead to the need for preoperative neoadjuvant therapy to decrease the risk of recurrence. The modalities commonly used for the primary staging of rectal cancer include EUS, computed tomography, and magnetic resonance imaging. EUS may be accompanied by the use of EUS-fine-needle aspiration to provide cytological confirmation. In this review, we take a deeper look into the role of EUS in the accurate staging of rectal cancer, how it compares to other modalities for the same, and how its role has changed in the last decade.

Endoscopic ultrasound in oncology: An update of clinical applications in the gastrointestinal tract

An accurate staging is necessary to select the best treatment and evaluate prognosis in oncology. Staging usually begins with noninvasive imaging such as computed tomography, magnetic resonance imaging or positron emission tomography. In the absence of distant metastases, endoscopic ultrasound plays an important role in the diagnosis and staging of gastrointestinal tumors, being the most accurate modality for local-regional staging. Its use for tumor and nodal involvement in pre-surgical evaluation has proven to reduce unnecessary surgeries. The aim of this article is to review the current role of endoscopic ultrasound in the diagnosis and staging of esophageal, gastric and colorectal cancer.

Diagnostic Value of Endorectal Ultrasound in Preoperative Assessment of Lymph Node Involvement in Colorectal Cancer: a Meta-analysis

BACKGROUND

Nodal invasion by colorectal cancer is a critical determinant in estimating patient survival and in choosing appropriate preoperative treatment. The present meta-analysis was designed to evaluate the diagnostic value of endorectal ultrasound (EUS) in preoperative assessment of lymph node involvement in colorectal cancer.

MATERIALS AND METHODS

We systematically searched PubMed, Web of Science, Embase, and China National Knowledge Infrastructure (CNKI) databases for relevant studies published on or before December 10th, 2014. The sensitivity, specificity, likelihood ratios, diagnostic odds ratio (DOR) and area under the summary receiver operating characteristics curve (AUC) were assessed to estimate the diagnostic value of EUS. Subgroup analysis and meta-regression were performed to explore heterogeneity across studies.

RESULTS

Thirty-three studies covering 3,016 subjects were included. The pooled sensitivity and specificity were 0.69 (95%CI: 0.63-0.75) and 0.77 (95%CI: 0.73-0.82), respectively. The positive and negative likelihood ratios were 3.09 (95%CI: 2.52-3.78) and 0.39 (95%CI: 0.32-0.48), respectively. The DOR was 7.84 (95%CI: 5.56-11.08), and AUC was 0.80 (95%CI: 0.77-0.84).

CONCLUSIONS

This meta-analysis indicated that EUS has moderate diagnostic value in preoperative assessment of lymph node involvement in colorectal cancer. Further refinements in technology and diagnostic criteria are necessary to improve the diagnostic accuracy of EUS.

The accuracy of MRI, endorectal ultrasonography, and computed tomography in predicting the response of locally advanced rectal cancer after preoperative therapy: A metaanalysis

BACKGROUND

To perform a metaanalysis to determine and compare the diagnostic performance of MRI, endorectal ultrasonography (ERUS), and computed tomography (CT) in predicting the response of locally advanced rectal cancer after preoperative therapy.

METHODS

All previously published articles on the role of MRI, CT, and/or ERUS in predicting the response of rectal cancer to preoperative therapy were collected. We divided the objective in 3 parts: the accuracy to assess (i) complete response, (ii) to detect T4 tumors with invasion to the circumferential resection margin (CRM), and (iii) to predict the presence of lymph node metastasis. The pooled estimates of, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated using a bivariate mixed effect analysis.

RESULTS

Forty-six studies comprising 2,224 patients were included. (i) The pooled accuracy to assess complete tumor response were (a) 75% for MRI, (b) 82% for ERUS, (c) and 83% for CT. (ii) Pooled accuracy to detect T4 tumors with invasion to the CRM were (a) 88% and (b) 94% for ERUS. (iii) Pooled accuracy to predict the presence of lymph node metastasis was (a) 72% for MRI, (b) 72% for ERUS, (c) and 65% for CT.

CONCLUSION

MRI, CT, and ERUS cannot be used to predict complete response of locally advanced rectal cancer after CRT. In addition, the positive predictive value for these imaging techniques is low for the assessment of tumor invasion in the CRM. The accuracy of the modalities to predict the presence of metastatic lymph node disease is also low.

Systematic review and meta-analysis of the accuracy of MRI and endorectal ultrasound in the restaging and response assessment of rectal cancer following neoadjuvant therapy

AIM

Restaging imaging by MRI or endorectal ultrasound (ERUS) following neoadjuvant chemoradiotherapy is not routinely performed, but the assessment of response is becoming increasingly important to facilitate individualization of management.

METHOD

A search of the MEDLINE and Scopus databases was performed for studies that evaluated the accuracy of restaging of rectal cancer following neoadjuvant chemoradiotherapy with MRI or ERUS against the histopathological outcome. A systematic review of selected studies was performed. The methodological quality of studies that qualified for meta-analysis was critically assessed to identify studies suitable for inclusion in the meta-analysis.

RESULTS

Sixty-three articles were included in the systematic review. Twelve restaging MRI studies and 18 restaging ERUS studies were eligible for meta-analysis of T-stage restaging accuracy. Overall, ERUS T-stage restaging accuracy (mean [95% CI]: 65% [56-72%]) was nonsignificantly higher than MRI T-stage accuracy (52% [44-59%]). Restaging MRI is accurate at excluding circumferential resection margin involvement. Restaging MRI and ERUS were equivalent for prediction of nodal status: the accuracy of both investigations was 72% with over-staging and under-staging occurring in 10-15%.

CONCLUSION

The heterogeneity amongst restaging studies is high, limiting conclusive findings regarding their accuracies. The accuracy of restaging imaging is different for different pathological T stages and highest for T3 tumours. Morphological assessment of T- or N-stage by MRI or ERUS is currently not accurate or consistent enough for clinical application. Restaging MRI appears to have a role in excluding circumferential resection margin involvement.

Role of endoscopic ultrasonography in the loco-regional staging of patients with rectal cancer

The prognosis of rectal cancer (RC) is strictly related to both T and N stage of the disease at the time of diagnosis. RC staging is crucial for choosing the best multimodal therapy: patients with high risk locally advanced RC (LARC) undergo surgery after neoadjuvant chemotherapy and radiotherapy (NAT); those with low risk LARC are operated on after a preoperative short-course radiation therapy; finally, surgery alone is recommended only for early RC. Several imaging methods are used for staging patients with RC: computerized tomography, magnetic resonance imaging, positron emission tomography, and endoscopic ultrasound (EUS). EUS is highly accurate for the loco-regional staging of RC, since it is capable to evaluate precisely the mural infiltration of the tumor (T), especially in early RC. On the other hand, EUS is less accurate in restaging RC after NAT and before surgery. Finally, EUS is indicated for follow-up of patients operated on for RC, where there is a need for the surveillance of the anastomosis. The aim of this review is to highlight the impact of EUS on the management of patients with RC, evaluating its role in both preoperative staging and follow-up of patients after surgery.

Performance of endoscopic ultrasound in staging rectal adenocarcinoma appropriate for primary surgical resection

BACKGROUND & AIMS

Endoscopic ultrasound (EUS) often is used to stage rectal cancer and thereby guide treatment. Prior assessments of its accuracy have been limited by small sets of data collected from tumors of varying stages. We aimed to characterize the diagnostic performance of EUS analysis of rectal cancer, paying particular attention to determining whether patients should undergo primary surgical resection.

METHODS

We performed a retrospective observational study using procedural databases and electronic medical records from 4 academic tertiary-care hospitals, collecting data on EUS analyses from 2000 through 2012. Data were analyzed from 86 patients with rectal cancer initially staged as T2N0 by EUS. The negative predictive value (NPV) was calculated by comparing initial stages determined by EUS with those determined by pathology analysis of surgical samples. Logistic regression models were used to assess variation in diagnostic performance with case attributes.

RESULTS

EUS excluded advanced tumor depth with an NPV of 0.837 (95% confidence interval [CI], 0.742-0.908), nodal metastasis with an NPV of 0.872 (95% CI, 0.783-0.934), and both together with an NPV of 0.767 (95% CI, 0.664-0.852) compared with pathology analysis. Incorrect staging by EUS affected treatment decision making for 20 of 86 patients (23.3%). Patient age at time of the procedure correlated with the NPV for metastasis to lymph node, but no other patient features were associated significantly with diagnostic performance.

CONCLUSIONS

Based on a multicenter retrospective study, EUS staging of rectal cancer as T2N0 excludes advanced tumor depth and nodal metastasis, respectively, with an approximate NPV of 85%, similar to that of other modalities. EUS has an error rate of approximately 23% in identifying disease appropriate for surgical resection, which is lower than previously reported.

Restaging of locally advanced rectal cancer with magnetic resonance imaging and endoluminal ultrasound after preoperative chemoradiotherapy: a systemic review and meta-analysis

BACKGROUND

Magnetic resonance imaging and endoluminal ultrasound play an important role in the restaging of locally advanced rectal cancer after preoperative chemoradiotherapy, yet their diagnostic accuracy is still controversial.

OBJECTIVE

Meta-analysis was performed to estimate the diagnostic performance of MRI and endoluminal ultrasound.

DATA SOURCES

Electronic databases from 1996 to March 2012 were searched.

STUDY SELECTION AND INTERVENTIONS

Either MRI or endoluminal ultrasound was used to restage rectal cancer after chemoradiotherapy or radiation.

MAIN OUTCOME MEASURES

T category, lymph node, and circumferential resection involvement were measured.

RESULTS

The sensitivity estimate for rectal cancer diagnosis (T0) by endoluminal ultrasound (37.0%; 95% CI, 24.0%-52.1%) was higher (p = 0.04) than the sensitivity estimate for MRI (15.3%; 95% CI, 6.5%-32.0%). For T3-4 category, sensitivity estimates of MRI and endoluminal ultrasound were comparable, 82.1% and 87.6%, whereas specificity estimates were poor (53.5% and 66.4%). For lymph node involvement, there was no significant difference between the sensitivity estimates for MRI (61.8%) and endoluminal ultrasound (49.8%). Specificity estimates for MRI and endoluminal ultrasound were 72.0% and 78.7%. For circumferential resection margin involvement, MRI sensitivity and specificity were 85.4% and 80.0%.

LIMITATIONS

To identify the heterogeneity, metaregression was performed on covariates. However, few of the covariates were identified to be statistically significant because of the lack of adequate original data.

CONCLUSION

Accurate restaging of locally advanced rectal cancer by MRI and endoluminal ultrasound is still a challenge. Identifying T0 rectal cancer by imaging is not reliable. Before performing surgery, restaging is important, but some of the T0-2 patients are likely overestimated as T3-4. Both modalities for lymph node involvement are not very good. Magnetic resonance imaging may be a good method to reassess circumferential resection margin.

Magnetic resonance imaging in rectal cancer: A surgeon’s perspective

Magnetic resonance imaging (MRI) in rectal cancer was first investigated in 1999 and has become almost mandatory in planning rectal cancer treatment. MRI has a high accuracy in predicting circumferential resection margin involvement and is used to plan neoadjuvant therapy. The accuracy of MRI in assessing mesorectal lymph nodes remains moderate, as there are no reliable criteria to assess nodal involvement. MRI seems to be good in assessing peritoneal involvement in upper rectal cancer; this however has been assessed in only a few studies and needs further research. For low rectal cancers, mesorectum is thin at the level of levator ani especially in relation to prostate; so predicting circumferential resection margin involvement is not easy. However high spatial resolution coronal imaging shows levator muscles, sphincter complex and intersphincteric plane accurately. This is used to stage low rectal tumors and plan plane of surgery (standard surgery, intersphincteric resection, Extralevator abdominoperineal resection). While most centres perform MRI post chemoradiotherapy, its role in accurate staging post neoadjuvant therapy remains debatable. THe role of Diffusion weighted MRI post neoadjuvant therapy is being evaluated in research settings.

Stage and size using magnetic resonance imaging and endosonography in neoadjuvantly-treated rectal cancer

AIM: To assess the stage and size of rectal tumours using 1.5 Tesla (1.5T) magnetic resonance imaging (MRI) and three-dimensional (3D) endosonography (ERUS).

METHODS: In this study, patients were recruited in a phase I/II trial of neoadjuvant chemotherapy for biopsy-proven rectal cancer planned for surgical resection with or without preoperative radiotherapy. The feasibility and accuracy of 1.5T MRI and 3D ERUS were compared with the histopathology of the fixed surgical specimen (pathology) to determine the stage and size of the rectal cancer before and after neoadjuvant chemotherapy. A Philips Intera 1.5T with a cardiac 5-channel synergy surface coil was used for the MRI, and a B-K Medical Falcon 2101 EXL 3D-Probe was used at 13 MHz for the ERUS. Our hypothesis was that the staging accuracy would be the same when using MRI, ERUS and a combination of MRI and ERUS. For the combination, MRI was chosen for the assessment of the lymph nodes, and ERUS was chosen for the assessment of perirectal tissue penetration. The stage was dichotomised into stage I and stage II or greater. The size was measured as the supero-inferior length and the maximal transaxial area of the tumour.

RESULTS: The staging feasibility was 37 of 37 for the MRI and 29 of 36 for the ERUS, with stenosis as a limiting factor. Complete sets of investigations were available in 18 patients for size and 23 patients for stage. The stage accuracy by MRI, ERUS and the combination of MRI and ERUS was 0.65, 0.70 and 0.74, respectively, before chemotherapy and 0.65, 0.78 and 0.83, respectively, after chemotherapy. The improvement of the post-chemotherapy staging using the combination of MRI and ERUS compared with the staging using MRI alone was significant (P = 0.046). The post-chemotherapy understaging frequency by MRI, ERUS and the combination of MRI and ERUS was 0.18, 0.14 and 0.045, respectively, and these differences were non-significant. The measurements of the supero-inferior length by ERUS compared with MRI were within 1.96 standard deviations of the difference between the methods (18 mm) for tumours smaller than 50 mm. The agreement with pathology was within 1.96 standard deviations of the difference between imaging and pathology for all tumours with MRI (15 mm) and for tumours that did not exceed 50 mm with ERUS (22 mm). Tumours exceeding 50 mm in length could not be reliably measured by ERUS due to the limit in the length of each recording.

CONCLUSION: MRI is preferable to use when assessing the size of large or stenotic rectal tumours. However, staging accuracy is improved by combining MRI with ERUS.

MRI after treatment of locally advanced rectal cancer: how to report tumor response--the MERCURY experience

OBJECTIVE

The Magnetic Resonance Imaging and Rectal Cancer European Equivalence (MERCURY) Study validated the use of MRI for posttreatment staging and its correlation with survival outcomes. As a consequence, reassessment of MRI scans after preoperative therapy has implications for surgical planning, the timing of surgery, sphincter preservation, deferral of surgery for good responders, and development of further preoperative treatments for radiologically identified poor responders.

CONCLUSION

In this article we report a validated systematic approach to the interpretation of MR images of patients with rectal cancer after chemoradiation.

Primary staging and response assessment postchemoradiotherapy in rectal cancer

SUMMARY Initial assessment of newly diagnosed patients with rectal cancer includes clinical examination, colonoscopy, pelvic MRI and CT scan of the thorax, abdomen and pelvis. Radiological staging can objectively evaluate both surgical and biological prognostic features of rectal cancer. MRI has emerged to be the most useful preoperative prognostic staging tool and it can predict the risk of tumor involvement of surgical circumferential resection margin. An agreed definition of favorable tumor response to chemoradiotherapy is controversial. The importance of detecting and assessing good versus poor responders to chemoradiotherapy is of increasing relevance. MRI has been found to be useful in assessing tumor response postchemoradiotherapy, especially the assessment of potential circumferential resection margin and magnetic resonance tumor regression grade. These imaging markers predict survival outcomes for good and poor responders and provide an opportunity for clinicians to offer additional neoadjuvant and adjuvant treatments to reduce local or distance failure for the poor responders.