Staging of rectosigmoid neoplasia with colonoscopic endoluminal ultrasonography

Preoperative classification of submucosal fibrosis in colorectal laterally spreading tumors by endoscopic ultrasonography

BACKGROUND AND STUDY AIMS

Although endoscopic submucosal dissection (ESD) is an established therapy for colon neoplasms including laterally spreading tumors (LSTs), its application to advanced fibrotic lesions is very difficult owing to the thin walls of the large intestine. We examined the ability of preoperative endoscopic ultrasonography (EUS) to predict lesion fibrosis in patients undergoing colorectal ESD.

PATIENTS AND METHODS

From 2009 to 2013, 58 LSTs were evaluated retrospectively with EUS and treated using colorectal ESD. The degree of submucosal fibrosis was determined during ESD and classified as F0 (no fibrosis), F1 (mild fibrosis), or F2 (severe fibrosis).

RESULTS

The sensitivity and specificity of fibrosis prediction by preoperative EUS of all cases were 77.8 % and 57.1 %, respectively. However, there was a high accuracy (97.2 %, 35/36) for only the 36 LSTs with clear and visible images. In one case, EUS diagnosed no fibrosis but significant fibrosis was found during ESD, the result of colon cancer invasion into the submucosa.

CONCLUSIONS

Preoperative EUS before colorectal ESD successfully predicted the degree of fibrosis in a number of cases.

Comparison of diagnostic accuracies of various endoscopic examination techniques for evaluating the invasion depth of colorectal tumors

This study was designed to assess the clinical value of magnifying endoscopy combined with EUS for estimating the invasion depth of colorectal tumors. We studied 168 colorectal adenomas and carcinomas that were sequentially examined by conventional endoscopy followed by magnifying endoscopy and EUS in the same session to evaluate invasion depth. Endoscopic images obtained by each technique were reassessed by 3 endoscopists to determine whether endoscopic resection (adenoma, mucosal cancer, or submucosal cancer with slight invasion) or colectomy (submucosal cancer with massive invasion or advanced cancer) was indicated. The accuracy of differential diagnosis was compared among the examination techniques. The rate of correct differential diagnosis according to endoscopic examination technique was similar. The proportion of lesions that were difficult to diagnose was significantly higher for EUS (15.5%) than for conventional endoscopy and magnifying endoscopy. Among lesions that could be diagnosed, the rate of correct differential diagnosis was the highest for EUS (89.4%), but did not significantly differ among three endoscopic examination techniques. When it is difficult to evaluate the invasion depth of colorectal tumors on conventional endoscopy alone, the combined use of different examination techniques such as EUS may enhance diagnostic accuracy in some lesions.

Colonoscopic high frequency mini-probe ultrasound is more accurate than conventional computed tomography in the local staging of colonic cancer

AIM

Colonoscopic high frequency mini-probe ultrasound was compared prospectively with CT in the local staging of colonic cancer.

METHOD

Consecutive patients undergoing surgical resection for colonic cancer were recruited. Preoperative 64-slice CT staging with multiplanar reconstruction was compared with colonoscopic high frequency mini-probe ultrasound using 12 MHz and 20 MHz probes. The three methods of staging (CT, 12 MHz ultrasound and 20 MHz ultrasound) were compared with the histological stage of the resected specimen. This was done using weighted kappa coefficients where weights of 0.7-0.8 were given to penalize disagreements of one level in either direction and weights of zero were given to penalize disagreements of more than one level in any direction.

RESULTS

In total, 38 patients with colonic cancer were included. They were located in the sigmoid (n = 20), descending (n = 5), ascending (n = 2) and transverse colon (n = 1) and in the caecum (n = 7) and splenic (n = 2) and hepatic (n = 1) flexure. Histopathological assessment revealed seven pT1, four pT2, 25 pT3 and two pT4 cancers. In relation to the pathology the weighted kappa coefficients were 0.36 (SE = 0.14), 0.81 (SE = 0.16) and 0.81 (SE = 0.17) for CT, ultrasound 12 MHz and ultrasound 20 MHz. Histopathologically 15 (39.5%) patients were lymph node positive. The sensitivity, specificity and kappa coefficient for detection of nodal disease for CT were 80%, 47.8% and 0.25 (SE = 0.14) compared with 80%, 82.5% and 0.62 for 12 MHz ultrasound (SD = 0.14) and 23%, 90.5% and 0.15 (SD = 0.13) for 20 MHz ultrasound.

CONCLUSION

Colonoscopic ultrasound is significantly more accurate than CT for T staging of colonic cancers. With respect to nodal status, 12 MHz ultrasound offers superior accuracy to CT or 20 MHz ultrasound.

Analysis of risk factors for lymph nodal involvement in early stages of rectal cancer: when can local excision be considered an appropriate treatment? Systematic review and meta-analysis of the literature

Background. Over the past ten years oncological outcomes achieved by local excision techniques (LETs) as the sole treatment for early stages of rectal cancer (ESRC) have been often disappointing. The reasons for these poor results lie mostly in the high risk of the disease's diffusion to local-regional lymph nodes even in ESRC. Aims. This study aims to find the correct indications for LET in ESRC taking into consideration clinical-pathological features of tumours that may reduce the risk of lymph node metastasis to zero. Methods. Systematic literature review and meta-analysis of casistics of ESRC treated with total mesorectal excision with the aim of identifying risk factors for nodal involvement. Results. The risk of lymph node metastasis is higher in G ≥ 2 and T ≥ 2 tumours with lymphatic and/or vascular invasion. Other features which have not yet been sufficiently investigated include female gender, TSM stage >1, presence of tumour budding and/or perineural invasion. Conclusions. Results comparable to radical surgery can be achieved by LET only in patients with T(1) N(0) G(1) tumours with low-risk histological features, whereas deeper or more aggressive tumours should be addressed by radical surgery (RS).

Risk factors for lymph node metastasis in pT1 and pT2 rectal cancer: a single-institute experience in 943 patients and literature review

BACKGROUND

Local excision has become an alternative for radical resection in rectal cancer for selected patients. The purpose of this study was to assess the clinicopathologic factors determining lymph node metastasis (LNM) in patients with T1-2 rectal cancer.

METHODS

Between January 1995 and December 2009, a total of 943 patients with pT1 or pT2 rectal adenocarcinoma received radical resection at a single institution. Clinicopathologic factors were evaluated by univariate and multivariate analyses to identify risk factors for LNM.

RESULTS

A total of 943 patients (544 men and 399 women) treated for T1-2 rectal cancer were included in this study. LNM was found in 188 patients (19.9%). In multivariate analysis, lymphovascular invasion (LVI; P < 0.001, hazard ratio 11.472), poor differentiation (PD; P = 0.007, hazard ratio 3.218), and depth of invasion (presence of pT2; P = 0.032, hazard ratio 1.694) were significantly related to nodal involvement. The incidence for LNM lesions in the presence of LVI, PD, and pT2 was 68.8, 50.0, and 23.1%, respectively, while that for pT1 carcinomas with no LVI or PD was 7.5%.

CONCLUSIONS

LVI, PD, and pT2 are independent risk factors predicting LNM in pT1-2 rectal carcinoma.

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

BACKGROUND

To date, the role of endoscopic ultrasound (EUS) in restaging locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (NAT) have not been thoroughly investigated.

AIM

To evaluate accuracy and clinical usefulness of EUS for both staging and restaging LARC.

METHODS

According to EUS staging, patients with LARC were enrolled in the study. Those who underwent surgery directly represented a control group useful for evaluating the accuracy of EUS in staging LARC. In the study group, EUS was repeated seven weeks after NAT, before surgery. The results of EUS were compared with the corresponding pTN stages.

RESULTS

From 2000 to 2006, 212 consecutive patients with RC underwent EUS staging. Among them EUS diagnosed 162 LARC (M/F = 93/69; mean age: 60 years [range 40-80]). The final study group included 85 patients with LARC. EUS restaging had an overall accuracy of 61% and 59% for T and N-stage, respectively. In the control group, the accuracy of EUS in staging LARC was 86% and 58% for T and N-stage, respectively.

CONCLUSION

EUS accurately stages LARC and enables appropriate decision-making, with selection of those patients who need NAT. On the other hand, EUS restaging of LARC after NAT has low accuracy and should not be used in clinical practice.

Does a learning curve exist in endorectal two-dimensional ultrasound accuracy?

BACKGROUND

Aim of the study was to assess adequacy of Colorectal Surgical Society of Australia and New Zealand (CSSANZ) endorectal ultrasound (ERUS) training and whether a subsequent learning curve exists.

METHODS

A prospective audit of ERUS for staging rectal cancer by a single surgeon from commencement of consultant practice was performed. Data were recorded in a prospectively maintained database. The audit commenced on completion of CSSANZ training. T- and N-stage were assessed clinically, then by ERUS prior to treatment and finally by histology over 8 years.

RESULTS

The results were compared over three time periods: the first a single year, then two three-year periods. Two hundred and seventy-two patients were examined. Two hundred and thirty-three were assessable for T-stage (13 no tumour excision, 26 long course pre-operative radiotherapy) and 142 for N-stage (74 endoanal excision, 17 proximal mesorectum un-assessable). Overall accuracy was 82% for T-stage and 73% for N-stage. Accuracy for T- and N-staging did not change significantly over the three time periods (T: 82.1, 82.3, 81.6%, P = 0.14; N: 83.3, 67.9, 74.2%, P = 0.31). The utility of ERUS was demonstrated by clinical assessment not being possible in 32% of cases and where the two modalities disagreed was correct 82% of the time.

CONCLUSIONS

Endorectal ultrasound rectal cancer staging is accurate for T-stage. Competency in ERUS can be achieved in the CSSANZ fellowship and accuracy does not improve with further experience. An ERUS accreditation scheme should be established for future trainees.

Endoscopic ultrasound may be unnecessary in the preoperative evaluation of intraductal papillary mucinous neoplasm

OBJECTIVES

Several imaging modalities are commonly performed during work-up of intraductal papillary mucinous neoplasm (IPMN), but guidelines do not suggest any one technique. The aim of this study was to evaluate tumour and duct measurements by computed tomography (CT) and endoscopic ultrasound (EUS) and their ability to predict high-grade dysplasia (HGD) and cancer within pancreatic IPMN.

METHODS

Patients with IPMN who underwent preoperative CT and EUS between 2001 and 2009 were selected. Data were gathered retrospectively from medical records.

RESULTS

The study group was comprised of 52 patients, 33% (17/52) of whom had HGD or cancer. On fine needle aspirate (FNA), neither carcinoembryonic antigen (CEA) >200 nor cytological analysis correlated with malignancy. In multivariate analysis, duct size ≥ 1.0 cm (P= 0.034) was a significant predictor of HGD or cancer, and diameter on CT scan (P= 0.056) approached significance. Lesion diameter of ≥ 2.5 cm on CT scan identified malignancy in 71% (12/17) of patients (P= 0.037). When analysed, all patients with HGD or cancer had a lesion diameter ≥ 2.5 cm and/or a duct diameter ≥ 1.0 cm by CT scan.

CONCLUSIONS

The use of radiographic criteria on CT including lesion size ≥ 2.5 cm and/or pancreatic duct diameter ≥ 1.0 cm appears to reliably identify patients with either HGD or invasive cancer. High-resolution CT scanning may obviate the need for EUS and FNA in patients with suspected IPMN.

Depth of tumor invasion independently predicts lymph node metastasis in T2 rectal cancer

OBJECTIVE

The aim of this study was to identify risk factors of lymph node metastasis (LNM) for T2 rectal cancer.

METHODS

From a prospectively maintained single-institution database, we identified 346 consecutive pT2 rectal cancers treated with total mesorectal excision from 1998 to 2009. Univariate and multivariate analyses were performed to identify risk factors associated with overall and intermediate/apical LNM. The incidence of overall and intermediate/apical LNM was analyzed by tree analysis.

RESULTS

Age, tumor location, pathological features, and depth of invasion were independent predictors for overall LNM. Tumor location, pathological features, and depth of invasion were independent predictors for intermediate/apical LNM. Tree analysis showed that the incidence of LNM was 7.7% for upper rectal cancer with favorable pathological features, and 3.4% for mid/lower rectal cancer without other identified risk factors. The incidence of intermediate/apical LNM was 5.7% for superficial T2 rectal cancer with favorable pathological features, and 3.1% for deep T2 rectal cancer locating in upper rectum with favorable pathological features.

CONCLUSIONS

Depth of invasion is an independent predictor for LNM in T2 rectal cancer. Using tree analysis, we identified a subset of patients with low risk of LNM who may be candidates of local excision.

Lymphovascular or perineural invasion may predict lymph node metastasis in patients with T1 and T2 colorectal cancer

BACKGROUND

The aim of the study was to evaluate factors for predicting lymph node metastasis in patients who had T1 and T2 colorectal cancer.

METHODS

A total of 224 patients with T1 or T2 colorectal cancers who underwent radical surgery with regional lymphadenectomy from January 1999 to January 2008 were analyzed.

RESULTS

Predictive factors for lymph node metastasis and prognostic factors were analyzed. Tumor stage was classified as T1 in 69 (30.8%) and T2 in 155 (69.2%) of patients. The overall incidence of lymph node metastasis was 21.0% (14.5% for T1 cancer and 23.9% for T2 cancer; P = 0.112). The node positive and negative groups were similar with regard to patient demographics, except that the former contained a significantly higher number of lymphovascular invasion and perineural invasion cases. During the median follow-up period of 49 months, the 5-year overall and disease-free survival rates for patients without lymph node metastasis were 97.1% and 94.6%, which were significantly higher than the rates for those with lymph node metastasis (85.5%, P = 0.008, and 82.0%, P = 0.007, respectively). A multivariate analysis revealed that lymph node status was the only significant independent prognostic factor for both overall survival (P = 0.025) and disease-free survival (P = 0.040). Moreover, the presence of lymphovascular invasion (P < 0.001) or perineural invasion (P = 0.004) was an independent predictor for lymph node metastasis.

CONCLUSION

Lymph node metastasis was the most powerful predictor for poorer survival in patients with T1 or T2 colorectal cancer. For patients with positive lymphovascular or perineural invasion, radical surgery should be recommended because of a greater chance for lymph node metastasis.

Can endoscopic ultrasound predict early rectal cancers that can be resected endoscopically? A meta-analysis and systematic review

BACKGROUND

Rectal cancers that are confined to the mucosa (T0) can be resected endoscopically. This can help the patient avoid transabdominal surgery. The published data on accuracy of endoscopic ultrasound (EUS) to predict T0 stage of rectal cancers has been varied.

AIM

To evaluate the accuracy of EUS in T0 staging of rectal cancers. METHOD (STUDY SELECTION CRITERIA): Only EUS studies confirmed by surgery were selected. T0 was defined as tumor confined to the mucosa. DATA COLLECTION AND EXTRACTION: Articles were searched in Medline, PubMed, and CENTRAL.

STATISTICAL METHOD

Pooling was conducted by both the fixed-effects model and random-effects model.

RESULTS

An initial search identified 3,360 reference articles. Of these, 339 relevant articles were selected and reviewed. Eleven studies (N = 1,791) which met the inclusion criteria were included in this analysis. Pooled sensitivity of EUS in diagnosing T0 was 97.3% (95% CI: 93.7-99.1). EUS had a pooled specificity of 96.3% (95% CI: 95.3-97.2). The positive likelihood ratio of EUS was 21.9 (95% CI: 16.3-29.7) and negative likelihood ratio was 0.08 (95% CI: 0.04-0.15). All the pooled estimates, calculated by fixed and random effect models, were similar. The P-value for Chi-squared heterogeneity for all the pooled accuracy estimates was >0.10.

CONCLUSIONS

EUS has excellent sensitivity and specificity, this helps accurately diagnose T0 stage of rectal cancers. Over the past two decades, the sensitivity and specificity of EUS to diagnose T0 stage of rectal cancers has remained high. This can help physicians offer endoscopic treatment to these patients, therefore EUS should be strongly considered for staging of early rectal cancers.

Colonoscopic ultrasound is associated with a learning phenomenon despite previous rigid probe experience

Colonoscopic ultrasound (CUS) enables total colonoscopic examination combined with staging of tumor. Rigid probe transrectal ultrasound (TRUS) is reliable in assessing rectal cancer. Both the modalities are associated with an initial learning curve. We evaluated the predictability CUS in preoperative staging of rectal cancer during the learning curve, despite experience with TRUS. Forty-four patients with non-obstructing rectal cancer were assessed by colonoscopy and colonic ultrasound using a 7.5 MHz rotating transducer. Accuracy of ultrasound staging was compared with pathological staging. Tumor staging and nodal staging at pathology and ultrasound were named pT, pN and uT, uN, respectively. The pathological staging was pT1 in two (4.5%), pT2 in 16 (36%), pT3 in 21 (48%) and pT4 in five (11.5%) rectal cancer specimens. CUS understaged the tumor in 11 cases and overstaged it in 10 cases. Overall, the positive predictive value was 61%, negative predictive value 73%, sensitivity 61%, and specificity 73%. Lymph nodes were not visualized in 14. The overall un-weighted kappa of CUS staging of RC was 0.18 (poor). The predictive value in tumor staging of CUS is suboptimal in the learning phase, despite previous experience with TRUS.

Accuracy of endoscopic ultrasound to diagnose nodal invasion by rectal cancers: a meta-analysis and systematic review

BACKGROUND

Nodal staging in patients with rectal cancer predicts prognosis and directs therapy. Published data on the accuracy of endoscopic ultrasound (EUS) for diagnosing nodal invasion in patients with rectal cancer has been inconsistent.

AIM

To evaluate the accuracy of EUS in diagnosing nodal metastasis of rectal cancers.

METHOD

Study Selection Criteria: Only EUS studies confirmed by surgical histology were selected. Data Collection and Extraction: Articles were searched in Medline, Pubmed, and CENTRAL.

STATISTICAL METHOD

Pooling was conducted by both fixed-effects model and random-effects model.

RESULTS

The initial search identified 3610 reference articles in which 352 relevant articles were selected and reviewed. Data were extracted from 35 studies (N = 2732) that met the inclusion criteria. Pooled sensitivity of EUS in diagnosing nodal involvement by rectal cancers was 73.2% (95% confidence interval [95% CI] 70.6-75.6). EUS had a pooled specificity of 75.8% (95% CI 73.5-78.0). The positive likelihood ratio of EUS was 2.84 (95% CI 2.16-3.72), and negative likelihood ratio was 0.42 (95% CI 0.33-0.52). All the pooled estimates, calculated by fixed- and random-effect models, were similar. SROC curves showed an area under the curve of 0.79. The P for chi-squared heterogeneity for all the pooled accuracy estimates was >.10.

CONCLUSIONS

EUS is an important and accurate diagnostic tool for evaluating nodal metastasis of rectal cancers. This meta-analysis shows that the sensitivity and specificity of EUS is moderate. Further refinement in EUS technologies and diagnostic criteria are needed to improve the diagnostic accuracy.

How good is endoscopic ultrasound in differentiating various T stages of rectal cancer? Meta-analysis and systematic review

Published data on accuracy of endoscopic ultrasound (EUS) in differentiating T stages of rectal cancers is varied. Study selection criteria were to select only EUS studies confirmed with results of surgical pathology. Articles were searched in Medline and Pubmed. Pooling was conducted by both fixed and random effects models. Initial search identified 3,630 reference articles, of which 42 studies (N = 5,039) met the inclusion criteria and were included in this analysis. The pooled sensitivity and specificity of EUS to determine T1 stage was 87.8% [95% confidence interval (CI) 85.3-90.0%] and 98.3% (95% CI 97.8-98.7%), respectively. For T2 stage, EUS had a pooled sensitivity and specificity of 80.5% (95% CI 77.9-82.9%) and 95.6% (95% CI 94.9-96.3%), respectively. To stage T3 stage, EUS had a pooled sensitivity and specificity of 96.4% (95% CI 95.4-97.2%) and 90.6% (95% CI 89.5-91.7%), respectively. In determining the T4 stage, EUS had a pooled sensitivity of 95.4% (95% CI 92.4-97.5%) and specificity of 98.3% (95% CI 97.8-98.7%). The p value for chi-squared heterogeneity for all the pooled accuracy estimates was > 0.10. We conclude that, as a result of the demonstrated sensitivity and specificity, EUS should be the investigation of choice to T stage rectal cancers. The sensitivity of EUS is higher for advanced disease than for early disease. EUS should be strongly considered for T staging of rectal cancers.

Endoscopic ultrasound staging of rectal cancer: diagnostic value before and following chemoradiation

BACKGROUND

Endoscopic ultrasound (EUS) has been shown to be a reliable tool for staging rectal cancer. Nevertheless, the accuracy of EUS after chemoradiation remains unclear; therefore the purpose of the present paper was to compare the accuracy of EUS staging for rectal cancer before and following chemoradiation.

METHODS

Patients with rectal cancer undergoing EUS staging were stratified into two groups. Group I consisted of 66 patients who underwent surgery following EUS staging without preoperative chemoradiation. Group II consisted of 25 patients who had EUS evaluation following chemoradiation. The EUS staging was compared to surgical/pathological staging.

RESULTS

The accuracy of the T staging for group I was 86% (57/66). Inaccurate staging was mainly associated with overstaging EUS T2 tumors. The accuracy of the N staging for group I was 71% (47/66). The accuracy of EUS for a composite T and N staging relevant to treatment decisions in group I was 91%. In group II, the accuracy of T and N staging was 72% (18/25) and 80% (20/25), respectively. Overstaging EUS T3 tumors accounted for most inaccurate staging. The EUS staging predicted post-chemoradiation T0N0 stage correctly in only 50% of cases.

CONCLUSIONS

Preoperative staging of rectal cancer by EUS is a useful modality in determining the need for preoperative chemoradiation. The EUS T staging following chemoradiation appears to be less accurate. Detection of complete response may be insufficient for selecting patients for limited surgical intervention.

Practice patterns and attitudes toward the role of endoscopic ultrasound in staging of gastrointestinal malignancies: a survey of physicians and surgeons

BACKGROUND AND AIMS

It is unknown how physician specialties other than gastroenterologists that manage gastrointestinal (GI) malignancies utilize endoscopic ultrasound (EUS) in their practices. The aim of this study was to (i) assess the proportion of gastroenterologists, oncologists, and surgeons that utilize EUS for staging of GI malignancies; (ii) assess the general availability of EUS; and (iii) determine which factors are associated with the use and availability of EUS.

METHODS

A self-administered questionnaire was mailed out to 1,200 randomly selected gastroenterologists, oncologists, and surgeons throughout the United States.

RESULTS

The data was analyzed from 521 (43%) responses. There were 60% respondents who had EUS available within their practices. There was greater availability of EUS within the practices of surgeons (81%; p < 0.001), within academic practices (87%; p= < 0.001), and in practices that serve a population >500,000 (p < 0.001). The majority of respondents (71%) utilized EUS in their practices. There was a similar utilization of EUS across specialties (p= NS). There was greater utilization of EUS in academic centers (82%; p < 0.001), in practices that served a community of >500,000 (p= 0.003), and among respondents who had been in practice for less than 5 yr (p= 0.005). Employing logistic regression models for utilization of EUS, lesser number of years in practice, and availability of EUS were found to be the only significant predictors of utilization.

CONCLUSIONS

The majority of practitioners utilized EUS in management of GI malignancies. There was similar utilization of EUS across specialties. EUS is available to the majority of practitioners who manage GI malignancies.

Imaging for Predicting the Risk Factors—the Circumferential Resection Margin and Nodal Disease—of Local Recurrence in Rectal Cancer: A Meta-Analysis

The aim of the present study was to conduct a meta-analysis of English literature on the accuracy of preoperative imaging in predicting the two most important risk factors for local recurrence in rectal cancer, the circumferential resection margin (CRM) and the nodal status (N-status). Articles published between 1985 and August 2004 that report on the diagnostic accuracy of endoluminal ultrasound (EUS), computed tomography (CT), or magnetic resonance imaging (MRI) in the evaluation of lymph node involvement were included. A similar search was done for the assessment of the circumferential resection margin in rectal cancer in the period from January 1985 till January 2005. The inclusion criteria were as follows: (1) more than 20 patients with histologically proven rectal cancer were included, (2) histology was used as the gold standard, and (3) results were given in a 2 x 2 contingency table or this table could otherwise be extracted from the article by two independent readers. Based on the results summary receiver operating characteristic (ROC) curves were constructed. Only 7 articles matching inclusion criteria were found concerning the CRM. The meta-analysis shows that MRI is rather accurate in diagnosing a close or involved CRM. For nodal status 84 articles could be included. The diagnostic odds ratio of EUS is estimated at 8.83. For MRI and CT, the diagnostic odds ratio are 6.53 and 5.86, respectively. The results show that EUS is slightly, but not significantly, better than MRI or CT for identification of nodal disease. There is no significant difference between the different modalities with respect to staging nodal status. At present, MRI is the only modality that predicts the circumferential resection margin with good accuracy, making it a good tool to identify high and low risk patients. Predicting the N-status remains a problem for the radiologist for every modality, although considering the new developments in MR imaging, this may change in the near future.

Assessment of publication bias in the reporting of EUS performance in staging rectal cancer

INTRODUCTION

Endoscopic ultrasound (EUS) has emerged as a promising diagnostic modality for locoregional staging of rectal cancer. However, as with any new technology, publication bias, the selective reporting of studies featuring positive results, may result in overestimation of the capability of EUS. The aim of this study was to systematically assess for publication bias in the reporting of the accuracy of EUS in staging rectal cancer.

METHODS

A MEDLINE search for all published estimates of EUS accuracy in staging rectal cancer between 1985 and 2003 was performed. All retrieved studies were fully published in the English literature. Published studies were analyzed and the following information was abstracted: accuracy of EUS, year of publication, number of subjects studied, impact factor of journal, and type of journal (gastroenterology, surgery, radiology, other).

RESULTS

Two hundred and two abstracts were reviewed; 41 publications met the stated criteria for inclusion. EUS T-staging accuracy was reported in 40 studies while EUS N-staging accuracy was reported in 27 studies. The experience of 4, 118 subjects was reported with an overall mean T-staging accuracy of 85.2% (median, 87.5%) and N-staging accuracy of 75.0% (median, 76.0%). There was a paucity of smaller studies expressing low EUS accuracy rates. Both T-staging and N-staging accuracy rates also declined over time with the lowest rates reported in more recent literature.

CONCLUSION

The performance of EUS in staging rectal cancer may be overestimated in the literature due to publication bias. This inflated estimate of the capability of EUS may lead to unrealistic expectations of this technology.

The role of colonoscopic endoanal ultrasound scanning (EUS) in selecting patients suitable for resection by transanal endoscopic microsurgery (TEM)

OBJECTIVE

This study was performed to assess the accuracy of colonoscopic endoanal ultrasound scanning (EUS) in the selection of patients with rectal neoplasia suitable for local excision by transanal endoscopic microsurgery (TEM). Our policy is to offer TEM to patients with premalignant (T0) lesions or with T1 tumours that have early disease.

PATIENTS AND METHODS

Data were collected prospectively on all patients undergoing EUS for the assessment of rectal neoplasia at our institution over a six-year period. A colonoscopic EUS probe was used to determine whether the tumour breached the muscularis propria (the interface between T1 and T2 disease). Subsequently patients underwent surgical resection, including TEM for those with T0/1 disease. The preoperative stage predicted by EUS (uT stage) was compared to the postoperative histopathological stage of the resected specimens (pT stage).

RESULTS

One hundred and fifty-six EUS examinations were evaluated. Sixty-two patients went on to have TEM whilst the remaining 94 had another form of surgery. Of the 62 patients undergoing TEM, 3 were overstaged on EUS. No patients were understaged, giving an accuracy of 95%. Of the 94 patients undergoing an alternative procedure, 5 were overstaged on EUS as having T2 tumours when in fact their histology was T1. Accuracy of EUS at predicting more advanced disease fell to 89%, giving an overall accuracy of 92%.

CONCLUSIONS

EUS is accurate at predicting T0/1 vs T2 disease in our institution, and we believe that it is a useful modality in assessing patient suitability for local excision.

Clinical presentation, imaging, and staging of anal cancer

Perianal symptoms are common, and benign anorectal conditions have clinical features not too dissimilar to those associated with anal canal carcinoma. To avoid delayed diagnosis, physicians need to be cognizant of the possibility of anal canal carcinoma, which can be effectively treated with chemoradiation therapy without the need for mutilating surgery. Appropriate imaging studies should be obtained for accurate staging of the disease and for follow-up examinations after definitive treatment.

Impact of Preoperative Staging and Chemoradiation Versus Postoperative Chemoradiation on Outcome in Patients With Rectal Cancer: A Decision Analysis

BACKGROUND

Although radical resection and postoperative chemoradiation have been the standard therapy for patients with rectal cancer, preoperative staging by local imaging and chemoradiation are widely used. We used a decision analysis to compare the two strategies for rectal cancer management.

METHODS

We developed a decision model to compare survival outcomes after postoperative chemoradiation versus preoperative staging and chemoradiation in patients aged 70 years with resectable rectal cancer. In the postoperative chemoradiation strategy, patients undergo radical resection and receive postoperative chemoradiation. In the preoperative staging and chemoradiation strategy, patients with locally advanced cancer receive preoperative chemoradiation and radical resection, whereas those with amenable localized tumors undergo local excision. The cohorts of patients were entered into a Markov model incorporating age-adjusted and disease-specific mortality. Outcomes were evaluated by modeling 5-year disease-specific survival for preoperative chemoradiation as less than, equal to, or greater than that of postoperative chemoradiation. Base-case probabilities were derived from published data; the Surveillance, Epidemiology, and End Results (SEER) Program database; and U.S. Life Tables. One-way and two-way sensitivity analyses were performed. The outcome measures were life expectancy and quality-adjusted life expectancy.

RESULTS

Life expectancy and quality-adjusted life expectancy were 9.72 and 8.72 years, respectively, in the postoperative chemoradiation strategy. In the preoperative staging and chemoradiation strategy, life expectancy was 9.36, 9.72, and 10.09 years and quality-adjusted life expectancy was 8.71, 9.04, and 9.37 years when 5-year disease-specific survival was less than, equal to, or greater than that of postoperative chemoradiation, respectively. The decision model was sensitive to differences in the long-term toxicity of pre- and postoperative chemoradiation. When the 5-year disease-specific survival for patients after pre- or postoperative chemoradiation was equal, the decision model was sensitive to surgical mortality and to the probability of residual lymph node disease after local excision.

CONCLUSION

If efficacy and toxicity after preoperative chemoradiation are equal to or better than that after postoperative chemoradiation in patients with locally advanced rectal cancer, then preoperative staging to select patients appropriate for preoperative chemoradiation is beneficial.

Staging of rectal carcinoma with transrectal ultrasonography

BACKGROUND AND AIMS

Transrectal ultrasonography (TRUS) has proven useful for loco-regional staging of rectal carcinoma in specialised centres, but the investigation is not widely used. The aim of this study was to audit the introduction of TRUS performed by surgeons without previous experience with ultrasonography.

MATERIAL AND METHODS

All patients admitted with rectal carcinoma in the period 1996-2002 entered this prospective, comparative study. TRUS with a stiff endorectal probe was performed preoperatively in 118 consecutive patients, 91 of whom subsequently had rectal resection without preoperative radiotherapy (PRT), and seven who had rectal resection after PRT. Twenty patients did not have resection. The main outcome measures was the feasibility of TRUS in staging of rectal cancer, and the accuracy of T- and N-staging, comparing TRUS with the histopathological examination of resected specimens.

RESULTS

TRUS was successful in 81/91 patients who underwent rectal resection without PRT. The accuracy of T-staging was 74% overall; 40% in five pT1 tumours, 81% in 26 pT2 tumours, 80% in 45 pT3 tumours and 25% in four pT4-tumours. With regard to perirectal tissue invasion, the sensitivity and specificity of TRUS was 82% and 84%, respectively, and the positive and negative predictive values were 89% and 71%, respectively. The accuracy of TRUS for N-staging was 65%. The sensitivity for detection of lymph node metastases was 41% and the specificity 68%. TRUS was unsuccessful in 21/118 patients, in 12/98 who had rectal resection, and in 9/ 20 who did not have resection, because of stenosis or high location of the tumour precluding correct placing of the probe.

CONCLUSIONS

TRUS is often unsuccessful in patients with advanced tumours, especially when the tumour is located in the upper rectum. The predictive values for perirectal tumour invasion were acceptable, but the sensitivity for detection of lymph node metastases was low. These results were obtained by surgeons without previous experience with ultrasonographic examinations.

Endoscopic ultrasound

Indications and the clinical utility of endosonography have evolved as new technology, such as linear array echoendoscopes and EUS-guided fine needle aspiration, has emerged. The most noteworthy of the EUS applications are for cancer staging; including rectal, pancreatic, lung, and esophageal malignancies. There is little doubt that EUS is a powerful tool for cancer imaging, but its clinical impact in patient care and management has yet to be validated in prospective outcome studies. Other imaging modalities such as positron emission tomography (PET), dual-phased helical CT, and MR imaging technology will undoubtedly provide increasingly accurate diagnostic and staging information for gastrointestinal diseases. EUS imaging alone may assume a less significant role in relation to these noninvasive modalities in the future. EUS-guided FNA, as well as therapeutic EUS applications, will likely continue to expand in scope and play an important role in clinical medicine for many years to come.

Venous invasion may predict lymph node metastasis in early rectal cancer

AIM

The aim of this study was to evaluate the role of histopathological and demographic characteristics in predicting lymph node metastasis in patients with adenocarcinoma of the rectum confined to the mucosal and submucosal layers.

METHODS

Fifty-nine patients with early rectal cancer underwent resection of the rectum including lymph nodes and five showed lymph node metastasis (8.6%). Pathology slides of these patients were reviewed by a single pathologist. Demographic and clinical characteristics of these 59 patients were correlated with the existence of nodal metastasis. Formal tests of comparability were carried out by using Fisher's exact test. Logistic regression models were fitted to data to examine possible relationships with 12 covariates measured from each patient and to obtain corresponding odds ratios (as well as a 95% confidence interval for the odds ratios). These covariates included age at surgery, gender, morphology, histology, degree of differentiation, Haggitt's classification for polyps according to the level of invasion, lymphatic and venous invasion, desmoplastic reaction, degree of lymphocytic invasion, presence of lymphoid follicles and presence of infiltrating or pushing margins.

RESULTS

A significantly higher rate of lymph node metastasis occurs in the presence of venous invasion (P < 0.01). Venous invasion was present in three of five (60%) patients with lymph node metastasis and only four of 54 (7%) patients without lymph node metastasis. Other variables did not achieve statistical significance.

CONCLUSIONS

Only the presence of venous invasion was found to be highly significant. The odds ratio of lymph node metastasis increased 18-fold for a patient who had venous invasion compared with a patient who did not. This suggests that the presence of venous invasion in early rectal cancer may provide valuable information to determine which patients would benefit from radical surgery, or adjuvant radiation therapy after sphincter-sparing surgery owing to an increased risk of lymph node metastasis.

Transit endoscopic ultrasound of colorectal cancer using a 12 MHz catheter probe

The objective of this study was to examine the accuracy of a 12 MHz ultrasound catheter probe in the pre-operative staging of colorectal cancer by assessing the depth of tumour infiltration and involvement of pericolonic lymph nodes. 159 patients with colorectal cancer who underwent ultrasound examination with a 12 MHz catheter probe were studied prospectively. The results of this imaging procedure were compared with the histological findings of the resected specimens. The accuracy of the 12 MHz ultrasound catheter probe for depth of invasion (T category) was 85% (131/154) for all tumours, 87% (46/53) for pT1 tumours, 60% (9/15) for pT2 tumours, 89% (74/83) for pT3 tumours and 67% (2/3) for pT4 tumours. The accuracy for tumours of the rectum and colon was 81% and 89%, respectively. The accuracy of the probe for nodal staging (N category) was 67% (76/114) overall. The sensitivity was 70% (33/47), the specificity 64% (43/67), the positive predictive value 58% (33/57) and the negative predictive value 75% (43/57). Endoscopic ultrasound using a 12 MHz catheter probe accurately assessed tumour stage, although nodal staging remained suboptimal. This method may aid in the selection of treatment for patients with colorectal cancer.

Source of errors in the evaluation of early rectal cancer by endoluminal ultrasonography

PURPOSE

Although preoperative evaluation of early rectal cancers can be done by endoluminal sonography and by means of colonoscopic findings, it is still controversial whether endoluminal sonography can effectively discriminate mucosal from submucosal lesions. This study was performed to verify objective causes of errors in the evaluation of early rectal cancer (T0/1) using a review of videotaped endoluminal sonography images.

METHODS

Eighty-nine patients with suspected early rectal cancer on endoluminal sonography were included. Two different scanners with appropriate probes were used according to tumor location, i.e., transrectal ultrasonography was used to scan up to 8 cm of the rectum above the anal verge, whereas endoscopic ultrasonography was used to assess higher lesions. Endoluminal sonography images were correlated with histologic infiltration and were reevaluated carefully to identify sources of errors.

RESULTS

Sensitivity and specificity were 83.1 and 96.5 percent, respectively, for tumor staging, whereas sensitivity was very low compared with specificity (16.7 vs. 90.2 percent) for metastatic lymph nodes. Endoluminal sonography images showed irregularity of the underlying tumor border (P < 0.01) and hypoechoic blurring or cutoff of the inner and outer hypoechoic layers (P < 0.001), all of which closely correlated with histologic infiltration of tumor cells. Overstaging occurred more than twice as often as understaging in tumor reevaluation (14 vs. 5 occurrences). In contrast to tumors, lymph nodes showed a similar amount of both overstaging (four cases) and understaging (five cases). The sources of errors were summarized as five types: false instrumentation, interpretive errors, anatomic defects, imaging failure, and inevitable errors.

CONCLUSIONS

Because false instrumentation, interpretive errors, and anatomic defects were considered preventable, 23 (82.1 percent) of the 28 errors might have been avoided. Therefore, a clear image by endoluminal sonography can effectively distinguish mucosal from submucosal lesions in early rectal cancer.

Role of endoscopy in staging colorectal cancer

The treatment of colorectal cancer depends in large measure on the depth of tumor invasion and the extent of lymph node involvement. Endoscopic ultrasonography (EUS) has added a new dimension to the evaluation of tumor invasion and lymph node involvement in gastrointestinal cancer. The overall EUS accuracy for colorectal cancer T-staging is 78%, specificity is 73%, and sensitivity is 94%. In determining the nodal involvement by tumor, EUS has an accuracy of 75%, specificity of 73%, and sensitivity of 74%. Comparison with computerized tomography (CT), magnetic resonance imaging (MRI), and MRI with endorectal coil (MRIEC) shows that EUS is an effective single modality for assessing tumor penetration of the rectal wall. It does not, however, allow the assessment of distant metastatic disease. For assessing lymph node involvement, MRIEC offers the most comprehensive information.

Preoperative staging of rectal cancer using a 7.5 MHz front-loading US probe

BACKGROUND

Conventional echoendoscopes have disadvantages when used for staging colorectal cancer including the inability to pass the instrument through tight stenosis and limited maneuverability. This study evaluated the preoperative use of a newly developed 7.5 MHz front-loading ultrasound probe (FLUP) for local staging of rectal cancer.

METHODS

A 7.5 MHz FLUP, diameter 7.3 mm, was used in this study. The mechanical shaft portion of the probe can be passed in retrograde fashion through the accessory channel of a standard colonoscope. Thirty-nine patients with rectal cancer underwent ultrasonography with this probe. The tumors were staged using the TNM system, and the results were compared with the histologic findings of the resected specimens.

RESULTS

The FLUP proved to be satisfactory, with respect to maneuverability, for traversing stenosis and accurate recognition of small tumors under direct endoscopic control. The accuracy of the FLUP for T staging was 82% (32 of 39) for all tumors, 90% in pT1, and 79% in pT2 to pT4 tumors. The accuracy of the FLUP for N staging was 72% (23 of 32) overall. The sensitivity was 83%, the specificity was 65%, the positive predictive value was 59%, and the negative predictive value was 87%.

CONCLUSIONS

The 7.5 MHz FLUP appears to be useful for preoperative local staging of rectal cancer. This system makes it technically easier to image small cancers as well as advanced rectal cancers.