Staging of colorectal cancer

Preoperative staging of rectal cancer: the MERCURY research project

The development of a surgical technique that removes the tumour and all local draining nodes in an intact package, namely total mesorectal excision (TME) surgery, has provided the impetus for a more selective approach to the administration of preoperative therapy. One of the most important factors that governs the success of TME surgery is the relationship of tumour to the circumferential resection margin (CRM). Tumour involves the CRM in up to 20% of patients undergoing TME surgery, and results in both poor survival and local recurrence. It is therefore clear that the importance of the decision regarding the use of pre-operative therapy lies with the relationship of the tumour to the mesorectal fascia. In addition, a high-spatial-resolution MRI technique will identify tumours exhibiting other poor prognostic features, namely, extramural spread >5 mm, extramural venous invasion by tumour, nodal involvement, and peritoneal infiltration. The potential benefits of a selective approach using MRI-based selection criteria are evident. That is, over 50% of patients can be treated successfully with primary surgery alone without significant risk of local recurrence or systemic failure. Of the remainder, potentially dramatic improvements may be achieved through the use of intensive and targeted preoperative therapy aimed not only at reducing the size of the primary tumour and rendering potentially irresectable tumour resectable with tumour-free circumferential margins, but also at enabling patients at high risk of systemic failure to benefit from intensive combined modality therapy aimed at eliminating micrometastatic disease.

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.

Preoperative local staging of rectal cancer with endorectal MR imaging: comparison with histopathologic findings

The purpose of this prospective study was to assess the accuracy of endorectal MR imaging in the preoperative local staging of rectal cancers. In 20 cases, we correlated endorectal MR imaging findings with postoperative histopathologic staging according to TNM classification. The accuracy of endorectal MR for determining the T stage of rectal cancer was 85%. The sensitivity and specificity for detecting lymph node metastases were 90.9% and 55.5%, respectively.

Knowledge of indications for EUS among gastroenterologists and non-gastroenterologists

BACKGROUND

The level of awareness among non-gastroenterologists of the indications for EUS is unknown. This study assessed knowledge of the indications and the utility of EUS among gastroenterologists and non-gastroenterologists in a large multispecialty academic practice.

METHODS

A questionnaire was designed that tested knowledge of the indications for EUS with respect to 4 organ systems: esophagus, gastroduodenum, hepatopancreatobiliary system and colorectum. The questionnaire was distributed by electronic mail to gastroenterologists, general internists, non-gastroenterologist subspecialists, and surgeons in a large multispecialty practice.

RESULTS

The survey was distributed to 659 attending physicians of whom 227 (34%) replied: gastroenterologists (53%), internists (30%), non-gastroenterologist specialists (33%), and surgeons (28%). Knowledge of appropriate indications was highest among gastroenterologists (84.3%) compared with internists (68.9%), non-gastroenterologist specialists (65.4%), and surgeons (65.3%) (p < 0.0001). Among all non-gastroenterologists, knowledge of indications for hepatopancreatobiliary (mean 66.3% correct responses) and colorectal applications (64.0%) was inferior to knowledge of esophageal (71.5%) and gastroduodenal (83.5%) applications.

CONCLUSIONS

Internists, non-gastroenterologist specialists, and surgeons in a large multispeciality practice have moderate knowledge of the indications and the utility of EUS. Knowledge was at the lowest level for hepatopancreatobiliary and colorectal applications of EUS for all 3 groups of non-gastroenterologists. Future studies should focus on the education of non-gastroenterologists regarding the role of EUS and assess the impact of such education on the appropriateness of EUS referral patterns.

Clinical implications of quantification of mesorectal tumor invasion by endoscopic ultrasound: All T3 rectal cancers are not equal

BACKGROUND

Depth of invasion beyond the muscularis propria (MP) by T3 rectal cancer can vary. The purpose of the present paper was to determine if depth of invasion beyond MP, as assessed by preoperative endoscopic ultrasound (EUS), can predict tumor recurrence in patients with T3 rectal tumors.

METHODS

Patients with T3NxM0 rectal cancer, as determined by EUS, who underwent surgical resection (without preoperative neoadjuvant therapy) were reviewed by two blinded endosonographers. Tumors were classified as minimally invasive T3 (invasion </= 2 mm beyond MP by EUS) and advanced T3 disease (invasion > 2 mm).

RESULTS

Forty-two patients with T3 rectal tumors underwent surgical resection without receiving preoperative neoadjuvant therapy, of whom 14 had minimally invasive T3 and 28 had advanced T3 disease, as determined by preoperative EUS. Median follow up was 19 months. Tumor recurrence rates in minimally invasive and advanced T3 tumors were 14.3% and 39.3%, respectively, P = 0.02 (log-rank test). Adjusting for nodal status and postoperative adjuvant therapy administration, Cox proportional hazards model demonstrated advanced T3 disease (by EUS) to predict tumor recurrence, hazard ratio, 2.28 (95% confidence interval: 1.17-5.81), P = 0.01.

CONCLUSIONS

All T3 rectal tumors are not equal, with minimally invasive disease carrying a more favorable prognosis. By discriminating minimally invasive from advanced T3 disease, preoperative EUS provides important prognostic information. Further subclassification of T3 tumors, based on preoperative EUS staging, should be considered to enhance selection of patients for neoadjuvant therapy.

Endoscopic ultrasound for rectal cancer

The application of EUS has improved the way we evaluate and manage patients with rectal cancer. EUS has substantially greater sensitivity than CT in detecting advanced T stage tumors. Such improved sensitivity results in changes in preoperative therapy that would not otherwise have occurred without EUS. Although the addition of FNA provides little incremental effect on patient management, it carries the most potential for impacting management in those patients with early T stage disease, and its use should be considered in this subgroup of patients. Whether the accurate staging ability of EUS translates into improved outcomes in terms of reduced recurrence rates and ultimately prolonged survival remains uncertain. This will require further long-term outcome studies focusing on the endpoint of tumor recurrence and patient survival.

A prospective, blinded assessment of the impact of preoperative staging on the management of rectal cancer

BACKGROUND & AIMS

The influence of preoperative staging of rectal carcinoma on therapeutic decisions is uncertain. The use of fine-needle aspiration (FNA) of perirectal nodes in this setting has not been evaluated. The aim of this prospective, blinded study of patients with rectal cancer was to assess the impact of preoperative staging on treatment decisions and compare the tumor (T), nodal (N) staging performance characteristics of pelvic computed tomography (CT), rectal endoscopic ultrasonography (EUS), and EUS FNA.

METHODS

Eighty consecutive patients with newly diagnosed rectal cancer were prospectively evaluated. Therapy decisions were recorded after sequential disclosure of staging information to the patient's surgeon.

RESULTS

In 31% of patients (95% confidence interval, 21%-42%), EUS staging information changed the surgeon's original treatment plan based on CT alone. The further addition of FNA changed therapy in one patient. T staging accuracy was 71% (CT) and 91% (EUS) (P = 0.02); N staging accuracy was 76% (CT), 82% (EUS), and 76% (EUS FNA) (P = NS).

CONCLUSIONS

Preoperative staging with EUS results in more frequent use of preoperative neoadjuvant therapy than if staging was performed with CT alone. The addition of FNA only changed the management of one patient, whereas FNA did not significantly improve N staging accuracy over EUS alone. FNA seems to offer the most potential for impacting management in those patients with early T stage disease, and its use should be confined to this subgroup of patients. EUS is more accurate than CT for determining T stage of rectal carcinoma.

Cost-effectiveness of endoscopic ultrasonography in the evaluation of proximal rectal cancer

OBJECTIVE

Clinical trials demonstrate the superiority of preoperative over postoperative radiotherapy (XRT) in diminishing rates of local recurrence of transmurally infiltrating (T3/4) rectal tumors. The dosage and cost of preoperative XRT are less than postoperative XRT. The economic and health impact of transrectal endoscopic ultrasound (EUS) on rectal cancer management has not been described. The aim of this study was to apply a decision analysis model to compare the cost-effectiveness of three staging strategies in the evaluation of nonmetastatic proximal rectal cancer: abdominal and pelvic CT versus abdominal CT plus EUS versus abdominal CT plus pelvic magnetic resonance imaging.

METHODS

A decision model was designed using DATA Version 3.5 (TreeAge Software, Williamstown, MA), taking as entry criteria nonmetastatic proximal rectal cancer as determined by abdominal CT. In each arm, detection of transmural invasion prompted preoperative XRT. Baseline probabilities were varied through plausible ranges using sensitivity analysis. Cost inputs were based on Medicare professional plus facility fees. Endpoints were cost of treatment per patient and tumor recurrence-free rates. Cost-effectiveness (cost per prevention of local recurrence) and incremental cost-effectiveness ratios were calculated.

RESULTS

For proximal rectal tumors, evaluation with abdominal CT plus EUS is the most cost-effective approach ($24,468/yr) compared with abdominal CT plus pelvic magnetic resonance imaging ($24,870) and CT alone ($26,076). Both the magnetic resonance imaging- and CT-only approaches were dominated (i.e., more costly and less effective).

CONCLUSIONS

Abdominal CT plus EUS is the most cost-effective staging strategy for nonmetastatic proximal rectal cancer. Staging strategies incorporating EUS improve treatment allocation by achieving more accurate T staging, thereby optimizing the benefit of preoperative XRT to more advanced tumors.

Imaging of anorectal disease

BACKGROUND

Over the past two decades developments in imaging have changed the assessment of patients with anorectal disease.

METHODS

The literature on imaging techniques for anorectal diseases was reviewed over the period 1980-1999.

RESULTS

For the staging of primary rectal tumours, phased array magnetic resonance imaging (MRI) may be regarded as the most appropriate single technique. The combination of endosonography or endoluminal MRI with ultrasonography or spiral computed tomography yields similar results. All techniques have limitations both for local staging and in the assessment of distant metastases. MRI or positron emission tomography is preferable for tumour recurrence. For perianal fistula, high-resolution MRI (phased array or endoluminal) is the technique of choice. For constipation, defaecography is the preferred technique, nowadays with emphasis on functional information. The role of magnetic resonance defaecography is currently being evaluated. For faecal incontinence, endosonography and endoluminal MRI give similar results in detecting sphincter defects; endoluminal MRI has the advantage of detecting external sphincter atrophy.

CONCLUSION

High-resolution MRI, endosonography and defaecography are currently the optimal imaging techniques for anorectal disease.

Results of EUS in detecting perirectal lymph node metastases of rectal cancer: the pathologist makes the difference

BACKGROUND

Accurate preoperative staging of primary rectal cancer is mandatory because the result may affect therapeutic decisions. Endoscopic ultrasonography (EUS) is considered the most accurate method for locoregional staging, but the issue of possible variations in the assessment of its accuracy related to technical aspects of pathologic staging has never been raised. The aim of this study was to assess EUS results as determined by two different methods of dissection of surgical specimens.

METHODS

Among all cases with primary rectal cancer staged with EUS from April 1991 to April 1997, 131 patients underwent surgery without preoperative radiotherapy; EUS results for nodal staging were compared with those obtained by pathology. Resected specimens were examined using two different techniques (conventional vs. special dissection).

RESULTS

There was a significant decrease in diagnostic accuracy of EUS according to pathologic technique. Overall accuracy, sensitivity, specificity, positive and negative predictive values for conventional versus special dissection were as follows: 74.6% vs. 43. 3% (p = 0.0001), 67.8% vs. 21.8% (p = 0.0002), 79.1% vs. 67.8% (p = 0.14), 67.8% vs. 43.7% ( p = 0.02), and 79.1% vs. 43.2% (p = 0.0003), respectively. EUS sensitivity according to size of metastatic lymph nodes was significantly lower for nodes smaller than 5 mm in diameter (p = 0.025) when special dissection was performed because of a larger number of lymph nodes harvested.

CONCLUSIONS

Our findings raise concern about the results of EUS staging of lymph node metastases in rectal cancer. Further prospective studies on a node-by-node basis could clarify the real diagnostic yield of EUS.

Five primary synchronous neoplasms of the gastrointestinal tract

Multiple primary malignant neoplasms in a single patient have been well documented in the literature over the past hundred years. The lesions can be limited to a single organ or involve multiple organ systems. It is relatively common for patients with colorectal carcinoma or carcinoid tumors to have more than one primary neoplasm. Colonic lesions can be synchronous or metachronous in presentation and colonic or extracolonic in location. We present a patient with five primary synchronous neoplasms of the gastrointestinal tract, involving the stomach, small bowel, and colon. The patient had no evidence of metastatic disease and underwent resection of all the lesions. This case illustrates the need for a thorough search for additional neoplasms in the treatment of patients with cancer.

Primary tumour staging of gastric and colorectal cancer

Almost 15 years after its introduction, endosonography or endoscopic ultrasonography is an important technique in a wide range of gastrointestinal diseases. Other imaging techniques are CT, MRI and barium examination. There is a general consensus that the most important prognostic factor in gastric and colorectal carcinoma is the presence or absence of lymph node invasion, but malignant fixation of tumour through direct invasion of adjacent tissues also appears to be very important. Non-invasive preoperative assessment of tumour stage based on one or a combination of the above imaging modalities should allow appropriate treatment to be planned in each case.