Preoperative staging of rectal carcinoma

Pre-operative assessment of extramural invasion and sphincteral involvement in rectal cancer by magnetic resonance imaging with phased-array coil

OBJECTIVE

Pre-operative staging of rectal cancer should identify patients with extrarectal spread, who might benefit from pre-operative radiotherapy, and patients with minimal sphincteral involvement, who can avoid permanent colostomy. The aim of this study was to assess the accuracy of Magnetic Resonance Imaging (MRI) to predict tumour stage and sphincter status.

PATIENTS AND METHODS

Thirty-three patients with a rectal tumour were pre-operatively assessed by MRI with a phased-array coil. Imaging results were correlated with the final pathological findings.

RESULTS

The overall accuracy of pre-operative staging with MRI was 88% (k = 0.75) for extramural tumour invasion and 59% (k = 0.26) for lymph node metastases. MRI correctly evaluated the infiltration of the anal sphincters in 87% of patients (7 of 8 patients with low rectal tumour).

CONCLUSION

MRI provides the surgeon with valuable information regarding extramural tumour spread and sphincteral involvement, enabling appropriate selection of patients for pre-operative adjuvant therapy or sphincter-saving surgery.

Clinical utility and cost-effectiveness of routine preoperative computed tomography scanning in patients with colon cancer

BACKGROUND

The aims of this study were to assess the clinical utility of the practice of routine preoperative CT scanning and to determine its cost-effectiveness in colon cancer patients.

METHODS

A 6-year database of colon cancer patients treated at a veterans affairs medical was reviewed to determine the influence of preoperative CT scanning on clinical management. Cost analysis involved comparison of the institutional cost of CT scanning with the cost savings provided by avoiding nontherapeutic operations.

RESULTS

CT scans were obtained in 130 consecutive patients. CT scans provided information that was used in treatment planning in 43 (33%) patients and definitively altered the mode of treatment in 21 (16%) patients. The practice saved the institution $24,018 over 6 years.

CONCLUSION

Routine preoperative CT scanning definitively alters treatment in a small number of cases and is cost-effective.

Accuracy of thin section magnetic resonance using phased-array pelvic coil in predicting the T-staging of rectal cancer

Magnetic resonance (MR) imaging may contribute to staging rectal cancer and inform the decision regarding administration of pre-operative radiotherapy. The accuracy of MR has been debated. The aim of the present study was to determine the accuracy of thin section T2-weighted MR images in rectal cancer patients. MR results were compared with histological assessment of resection specimens. Over a 2-year period, 42 patients were studied. Histological staging was pT2 n = 13, pT3 n = 25 and pT4 n = 4. MR diagnostic accuracy was 74%. MR sensitivity and specificity was 62% and 79% for pT2 lesions, 84% and 59% for pT3 lesions and 50% and 76% for pT4 lesions. Estimation of tumour penetration by thin section MR imaging of rectal cancers using pelvic phased-array coil has moderate diagnostic accuracy. The limitations of MR should be acknowledged when selecting rectal cancer patients for pre-operative radiotherapy.

Development of a three-dimensional freehand endorectal ultrasound system for use in rectal cancer imaging

The initial study reporting the accuracy of an optically tracked endorectal ultrasound (TERUS) probe for the purpose of improving the staging of rectal cancer is presented here. In this work we describe the need for a more accurate ERUS system and why the incorporation of image guidance makes this goal feasible. A rectal phantom was constructed with five targets placed in positions where tumors normally occur. The locations of these targets were found using two different imaging modalities, CT and ultrasound, and the target registration error (TRE) between these two image sets was calculated. The average TRE of 33 image captures of the five targets using TERUS was 2.1 mm. This is a promising outcome because the desired tumor margins for rectal cancer are on the order of centimeters. These preliminary results support the proof of concept for a TERUS system that should improve ultrasound imaging in rectal cancer.

A prospective study assessing the efficacy of abdominal computed tomography scan without bowel preparation in diagnosing intestinal wall and luminal lesions in patients presenting to the emergency room with abdominal complaints

AIM: To evaluate the positive predictive value of abdominal non-prepared computed tomography (CT) for diagnosing intestinal lumen or wall lesions in patients presenting to the emergency room (ER) with abdominal complaints.

METHODS: For 1-year we prospectively evaluated all ER patients hospitalized after abdominal CT scan detected either intraluminal or intestinal wall lesions. These patients underwent colonoscopy serving as gold standard. Patients with prior abdominal pathology or CT findings of appendicitis or diverticulitis were excluded.

RESULTS: Five hundred and sixty-eight abdominopelvic CT scans were performed in the ER, 96 had positive colonic findings. Sixty-two patients were excluded, 46 because of diverticulitis or appendicitis, 16 because of prior abdominal pathology. Of the remaining 34 patients, 14 did not undergo colonoscopy during hospitalization. Twenty eligible patients were included in the study. The positive predictive value of the CT scans performed in the ER was calculated to be 45% (95% CI 25-67).

CONCLUSION: CT findings correlated with colonoscopic findings only in approximately half of the cases. Relying on non-prepared CT scan findings in planning patient management and colonoscopy may lead to unnecessary diagnostic work-ups.

Recurrence after transanal excision of T1 rectal cancer: should we be concerned?

PURPOSE

Transanal excision is an appealing treatment for low rectal cancers because of its low morbidity, mortality, and better functional results than transabdominal procedures. However, controversy exists about whether it compromises the potential for cure. Several, recent reports of high recurrence rates after local excision prompted us to review our results of transanal excision alone in patients with T1 rectal cancers.

METHODS

All patients with T1 low rectal cancer undergoing local excision alone between 1980 through 1998 were reviewed for local recurrence, distant metastasis, disease-free interval, results of salvage surgery, and overall and disease-free survival. Demographics, tumor size, distance from anal verge, and preoperative endoluminal ultrasound results also were recorded. Patients with poorly differentiated tumors, perineural or lymphovascular invasion, or with mucinous component were excluded.

RESULTS

Fifty-two patients underwent transanal excision during the study period. Five-year recurrence was estimated to be 29.38 percent (95 percent confidence interval, 15.39-43.48). For 52 patients, five-year, cancer-specific and overall survival rates were 89 and 75 percent respectively. Fourteen of 15 patients with recurrence underwent salvage treatment with 56.2 percent (95 percent confidence interval, 35.2-90) five-year survival rate. Gender, preoperative staging by endorectal ultrasound, distance from the anal verge, tumor size, location, and T1 status discovered after transanal excision of a villous adenoma did not influence local recurrence or tumor-specific survival.

CONCLUSIONS

Transanal excision for T1 rectal tumors with low-grade malignancy has a high rate of recurrence. Although overall cancer survival rates might be regarded as satisfactory, this high recurrence and low salvage rate raises the issue about the role of transanal excision alone for early rectal cancer and the possible need for adjuvant therapy or increased role of resective surgery.

Interpretation of magnetic resonance imaging for locally advanced rectal carcinoma after preoperative chemoradiation therapy

PURPOSE

Neoadjuvant concomitant chemoradiotherapy has been used in cases of locally advanced rectal cancer to preserve sphincter function, decrease local recurrence, and improve survival. Preoperative staging is essential for planning and providing optimal therapy. The purpose of this study is to determine the accuracy of staging with magnetic resonance imaging and to define any factors that interfere in interpretation of images obtained after preoperative chemoradiation therapy.

METHODS

Thirty-six patients with biopsy-proven, locally advanced rectal cancer were treated with preoperative concomitant 5-fluorouracil-based chemotherapy and radiation, followed six to eight weeks later by radical surgery. Preoperative magnetic resonance images were reinterpreted by one radiologist and the results compared with histopathologic staging.

RESULTS

T-level downstaging occurred in 10 of 36 patients (28 percent), and N-level downstaging occurred in 29 of 36 patients (80 percent) after completion of chemoradiation therapy. Pathologic complete remission after chemoradiotherapy occurred in five patients (12 percent). Of the 36 patients, 17 (47 percent) were overstaged and 2 (6 percent) were understaged in T-level, whereas 10 patients (28 percent) were overstaged and 3 patients (8 percent) were understaged in N-level. The accuracy of magnetic resonance imaging for determining depth of wall invasion was 47 percent, with 64 percent accuracy for nodal staging.

CONCLUSIONS

Magnetic resonance imaging is commonly used in staging of pelvic malignancies because of its fine resolution, but chemoradiotherapy may decrease its accuracy. Thickening of the rectal wall after radiation by marked fibrosis, and peritumoral infiltration of inflammatory cells and vascular proliferation may contribute to overestimation of stage. By contrast, pathologic residual cancer beneath normal mural structure after chemoradiation therapy may result in understaging of rectal cancer.

Preoperative chemoradiotherapy and total mesorectal excision surgery for locally advanced rectal cancer: correlation with rectal cancer regression grade

PURPOSE

Preoperative long-course chemoradiotherapy is recommended for rectal carcinoma when there is concern that surgery alone may not be curative. Downstaging of the tumor can be measured as rectal cancer regression grade (1-3) and may be of importance when estimating the prognosis. The aim of this study was to look at the long-term results of tumor regression in patients receiving long-course chemotherapy before surgical resection of rectal cancer.

METHODS

We reviewed those patients who received preoperative chemoradiotherapy followed by surgical resection for carcinoma of the mid rectum or distal rectum found to be stage T3/4 between January 1995 and November 1999. Patients received 45 to 50 Gy irradiation in 2-Gy fractions and an infusion of 5-fluorouracil. Surgical specimens were assessed for rectal cancer regression grade. Patients were followed up routinely with clinical examination, computed tomography, and colonoscopy.

RESULTS

Sixty-five patients with a mean age 65 (range, 32-83) years underwent chemoradiotherapy before surgical resection. Thirty patients (46 percent) were classified as rectal cancer regression Grade 1, with 9 patients (14 percent) having complete sterilization of the tumor. Fifty-three patients (82 percent) underwent a curative resection. Overall survival, with a median follow-up of 39 (range, 24-83) months, was 67 percent and was associated with tumor downstaging. The local recurrence rate was 5.8 percent in those patients who underwent a curative resection and was significantly lower with rectal cancer regression Grade 1 tumors (P = 0.03). Eight of nine patients (89 percent) whose tumor had been sterilized were alive and well with no recurrence of tumor at a median follow-up of 41 (range, 24-70) months.

CONCLUSIONS

Preoperative chemoradiotherapy resulted in significant regression of tumor. Overall survival was high and was associated with downstaging of tumor. The local recurrence rate was significantly lower with rectal cancer regression Grade 1 tumors and was not seen in patients with sterilized tumors.

Preoperative MRI of rectal cancer with and without rectal water filling: an intraindividual comparison

OBJECTIVE

The purpose of our study was to determine if a rectal distention using warm water may improve the accuracy of MRI for the preoperative staging of rectal carcinoma. SUBJECTS AND METHODS. Sixty-two patients with surgically proven rectal carcinomas underwent pelvic MRI before and after a rectal distention by warm water. Four radiologists, who were blinded to the study, reviewed each set of T1- and T2-weighted axial images obtained before and after the rectal distention and scored the image of the tumor. The accuracies for determining the tumor penetration of the outer wall of the rectum and the regional lymph node involvement were compared by analyzing the area under the receiver operating characteristic curve (A(z)).

RESULTS

For all reviewers, the tumor depiction scores were significantly higher in the distended images (3.8-3.9 for reviewers 1-4) than in the nondistended images (3.0-3.2) (p < 0.01). For determining the outer wall penetration, the accuracy of the three reviewers was significantly higher with the rectal distention images than with the nondistended images (p < 0.05). The mean accuracy of the all reviewers was significantly better with the distended images (A(z) = 0.922) than with the nondistended images (A(z) = 0.841) (p < 0.05). For determining the presence of regional lymph node involvement, all the reviewers came to similar conclusions in analyzing the two image sets.

CONCLUSION

Rectal distention by water filling may improve the depiction of a primary rectal tumor and the assessment accuracy of a perirectal tumor extension, but it does not improve the accuracy for determining the presence of regional lymph node involvement.

Does positron emission tomography change management in primary rectal cancer? A prospective assessment

PURPOSE

The influence of positron emission tomography in the management of recurrent rectal cancer is well established but its role in primary rectal cancer remains uncertain. This study therefore prospectively assesses the impact of position emission tomography scanning on the management of primary rectal cancer.

METHODS

Forty-six patients with advanced primary rectal cancer referred for consideration of adjuvant preoperative therapy underwent position emission tomography scanning. The referring physicians prospectively recorded each patient's stage following conventional imaging and the proposed treatment plan prior to position emission tomography scanning. This was then compared with subsequent stage and actual management implemented, and the appropriateness of position emission tomography-induced changes was noted by subsequent clinical follow-up.

RESULTS

The surgical management of 36 of 46 patients (78 percent) was unchanged as a result of position emission tomography, even though position emission tomography upstaged disease in 3 of 36 cases (8 percent) and downstaged disease in 5 of 36 cases (14 percent). In 8 of 46 cases (17 percent), management was altered because of the position emission tomography scan findings, including 6 cases (13 percent) in which surgery was cancelled and 2 other cases (4 percent) in which the radiotherapy field was changed. Where available, follow-up confirmed the appropriateness of position emission tomography-induced management change in each case. Two patients had a change in therapy independent of the position emission tomography scan due to clinical circumstances. Overall tumor stage was changed following position emission tomography in 18 of 46 patients (39 percent).

CONCLUSION

Position emission tomography scanning appears to accurately change the stage or appropriately alter the therapy of almost a third of patients with advanced primary rectal cancer. In view of this, we suggest that position emission tomography scanning be considered part of standard workup for such patients, particularly if neoadjuvant chemoradiation is being considered as part of primary management.

Local radiological staging of rectal cancer

Rectal cancer is a common malignancy with a highly variable outcome. Local recurrence is dependent upon tumour stage and surgical technique. The role of pre-operative imaging is to determine which patients may be safely managed by surgery alone and which need additional therapy in order to facilitate surgery and improve outcome. This decision depends on the distinction between those with early and advanced disease. While trans-rectal ultrasound has traditionally been used to answer this question, a role for magnetic resonance imaging (MRI) is increasingly argued. This review will focus on the treatment options for rectal cancer and the clinical questions that subsequently arise for the radiologist to answer.

Pre-operative short-course radiotherapy is associated with faecal incontinence after anterior resection

OBJECTIVE

To determine the contribution of total mesorectal excision (TME), short-course pre-operative radiotherapy (SCRT), the level of the anastomosis and other putative contributory factors to the incidence and degree of faecal incontinence after anterior resection of the rectum.

PATIENTS AND METHODS

Survivors of anterior resection of the rectum performed between February 1996 and February 2001, with a functioning anastomosis, were asked to complete a telephone questionnaire regarding their current bowel habit. Faecal incontinence was scored using the St. Mark's Incontinence Score.

RESULTS

The median age of 124 patients who completed the questionnaire was 76 years. Of these, 104 patients had neoplastic disease, 66 (53%) patients exhibited some degree of incontinence, median St. Marks' Score 6, interquartile range 3-10. There was a significant association between the anastomotic level, and the St. Mark's Score (P < 0.0001, linear regression). Male sex (P = 0.047), SCRT (P = 0.0014) and an anastomotic leak (P = 0.038) were associated with significantly higher incontinence scores. Age, splenic flexure mobilization, TME, anastomotic configuration or use of a temporary stoma had no detectable independent effect on incontinence scores.

CONCLUSIONS

Poor functional outcome following anterior resection was associated with a low anastomosis, SCRT or an anastomotic leak. The finding that SCRT was a predictor of postoperative incontinence emphasizes the need for stringent patient selection for this treatment modality.

Decreased detection rate of disseminated tumor cells of rectal cancer patients after preoperative chemoradiation: a first step towards a molecular surrogate marker for neoadjuvant treatment in colorectal cancer

OBJECTIVE

To compare the detection rates for rectal cancer cells in blood and bone marrow in patients with or without preoperative chemoradiation.

SUMMARY BACKGROUND DATA

Previous reports have postulated a resistance of disseminated tumor cells to antiproliferative agents because of tumor cell dormancy.

METHODS

Blood samples from 142 patients (pre, intra-, and postoperative samples) and bone marrow samples from 127 patients undergoing resection of rectal adenocarcinoma were analyzed for tumor cells using a cytokeratin (CK) 20-reverse transcription polymerase chain reaction. The results were stratified according to preoperative therapy.

RESULTS

In patients without preoperative chemoradiation, tumor cell detection in blood and bone marrow correlated to tumor stage (Cochran Armitage trend test, P < 0.05). Tumor cells were detected in 34 of 103 (33%) bone marrow and 65 of 117 (55.6%) blood samples of patients without neoadjuvant treatment versus in 4 of 24 (16.7%) bone marrow and in 10 of 25 (40%) blood samples of patients with neoadjuvant treatment. The tumor cell detection rate was significantly lower in the group having undergone chemoradiation (binary logistic regression analysis, P < 0.05). The overall and disease-free survival were significantly worse in patients with tumor cell detection in the bone marrow after neoadjuvant therapy.

CONCLUSIONS

Preoperative chemoradiation is associated with a decreased detection rate of rectal cancer cells in blood and bone marrow. These findings may explain the observed clinical benefit of patients with rectal cancer receiving chemoradiation. This is the first study suggesting that detection of disseminated rectal cancer cells may be useful for assessing the efficacy of neoadjuvant therapy.

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.

Adjuvant therapy for rectal cancer--the transatlantic view

In North America there are two conventional treatments for clinically resectable rectal cancer. First is surgery and, if the tumour is T3 and/or N1-2, this is followed by postoperative combined modality therapy. The second, for patients with ultrasound T3 or clinical T4 disease, is pre-operative combined modality therapy followed by surgery and postoperative chemotherapy. Pre-operative therapy (most commonly combined modality therapy) has gained acceptance as a standard adjuvant therapy. The potential advantages of this approach compared with postoperative therapy include less acute toxicity and enhanced sphincter preservation. Recently completed randomized trials in the US and Germany will provide a definitive answer to this theory. In contrast to the combined modality approach to pre-operative therapy a number of European centres advocate an intensive short course of radiation (5 Gy x 5 followed one week later by surgery). The only randomized trial which has revealed a significant advantage in survival is the Swedish Rectal Cancer Trial. The Dutch CKVO 95-04 TME trial did not confirm a survival advantage and two metanalyses report conflicting results. Due to selection bias, it is not possible accurately to compare the local recurrence and survival results of intensive short course radiation with conventional pre-operative combined modality therapy. The intensive short course radiation approach is not used in North America due to its higher toxicity and lack of sphincter preservation. In the Dutch trial the 5-year local recurrence was 12% with TME and was significantly decreased to 6% with pre-operative radiation. The 5-year local recurrence rate in the 324 patients with stage III disease who underwent a TME alone with negative margins was 20%. Therefore, despite TME surgery, radiation therapy is still a necessary component in the adjuvant management of rectal cancer.

Comparison of transrectal sonography and double-contrast MR imaging when staging rectal cancer

OBJECTIVE

The aim of this study was the prospective comparison of the diagnostic yield of transrectal sonography and double-contrast MR imaging for preoperative staging of rectal cancer. SUBJECTS AND METHODS. Thirty-nine rectal cancer patients (20 men, 19 women) underwent transrectal sonography performed with a 10-MHz endoanal probe and MR imaging (1.0 T or 1.5 T) using a whole-body coil. After rectal application of a superparamagnetic iron oxide MR contrast agent, T1- and T2-weighted images and gadolinium-enhanced double-contrast images were obtained. The results of examinations were compared with the histology of resected specimens.

RESULTS

Histopathology showed four stage T1, 11 stage T2, 18 stage T3, and six stage T4 tumors using the TNM staging system. Nodal metastases were seen in 16 patients. Transrectal sonography could not be performed in 11 patients because of the high location of the tumor. In the remaining 28 patients, the accuracy of transrectal sonography for T stage was 64% overall (patients not receiving radiation, 69%; patients receiving radiation, 60%) and 70% for N stage. In 39 patients, double-contrast MR imaging correctly identified the T stage with an accuracy of 64% overall (patients not receiving radiation, 75%; patients receiving radiation, 53%) and the N stage with an accuracy of 62%. The assessment of rectal wall penetration (Dukes' classification A versus B) revealed a sensitivity, specificity, and accuracy of 93%, 71%, and 82%, respectively, for transrectal sonography and 100%, 60%, and 85% for MR imaging.

CONCLUSION

If it is technically feasible, transrectal sonography is an accurate method for staging rectal cancer. In proximal or stenotic tumors, double-contrast MR imaging is the method of choice. Diagnostic accuracy of transrectal sonography and MR imaging is high for predicting bowel wall penetration.

Peri-operative radiotherapy for rectal cancer: the case for a selective pre-operative approach - the third way

Peri-operative radiotherapy has been used widely in addition to surgery in an attempt to reduce local recurrence (LR) following surgical resection of rectal cancer. Currently different groups follow different approaches with some routinely administering one weeks pre-operative radiotherapy to all cases of operable mobile cancer with others favouring postoperative chemoradiotherapy for selected high risk groups. In this review we bring together the changes in surgery, pathology and imaging that have occurred in recent years and together with the data from recent randomized pre-operative radiotherapy trials propose a logical and optimal way of managing rectal cancer. This third way is selective and pre-operative and should ensure a low rate of LR with radiotherapy reserved for those cases that need it.

Preoperative assessment of prognostic factors in rectal cancer using high-resolution magnetic resonance imaging

BACKGROUND

The aim was to determine the accuracy of preoperative magnetic resonance imaging (MRI) in the evaluation of pathological prognostic factors that influence local recurrence and survival in rectal cancer.

METHODS

Ninety-eight patients undergoing total mesorectal excision for biopsy-proven rectal cancer were assessed prospectively using high-resolution MRI for tumour (T) and nodal (N) staging using the tumour node metastasis classification, depth of extramural tumour spread, the presence or absence of extramural venous invasion, a threatened circumferential resection margin and serosal involvement at or above the peritoneal reflection. Preoperative magnetic resonance assessment of these prognostic factors was compared with histopathological findings in carefully matched whole-mount sections of the resection specimen.

RESULTS

There was 94 per cent weighted agreement (weighted kappa = 0.67) between MRI and pathology assessment of T stage. Agreement between MRI and histological assessment of nodal status was 85 per cent (kappa = 0.68). Although involvement of small veins by tumour was not discernible using MRI, large (calibre greater than 3 mm) extramural venous invasion was identified correctly in 15 of 18 patients (kappa = 0.64). MRI predicted circumferential resection margin involvement with 92 per cent agreement (kappa = 0.81). Seven of nine patients with peritoneal perforation by tumour (stage T4) were identified correctly using MRI.

CONCLUSION

High-resolution MRI of the rectum allows preoperative identification of important surgical and pathological prognostic risk factors. This may allow both better selection and assessment of patients undergoing preoperative therapy.

Retrospective study of acute toxicity following short-course preoperative radiotherapy

BACKGROUND

The use of short-course preoperative radiotherapy (25 Gy in five fractions over 1 week) in resectable rectal cancer reduces local recurrence but is associated with an increased risk of postoperative complications and late toxicity. This study aimed to identify those patients who are unlikely to benefit from short-course preoperative radiotherapy and the factors associated with acute toxicity.

METHODS

All patients who received short-course preoperative radiotherapy at a university hospital in 1998 and 1999 were included in this retrospective study. The association between complications occurring within 3 months and patient demographics, radiotherapy technique, surgical details and overall treatment time (OTT) was assessed by univariate and multivariate analysis.

RESULTS

The mortality rate at 30 days was 6 per cent in the 177 patients identified. Thirty-seven per cent of patients had either Dukes' A tumours, surgically incurable disease or positive circumferential margins. One or more complications occurred in 38 per cent of patients. On multivariate analysis an OTT of more than 13 days (P = 0.03), age (P = 0.02) and length of the radiotherapy field (P = 0.05) were associated with an increased risk of complications.

CONCLUSION

Surgery within 1 week of completing short-course preoperative radiotherapy improved preoperative staging and use of an optimal radiotherapy technique will result in fewer patients at risk of acute toxicity.

Radiology of colorectal cancer

In the past 20 years, the radiology of colorectal cancer has evolved from the barium enema to advanced imaging modalities like phased array magnetic resonance imaging (MRI), virtual colonoscopy and positron emission tomography (PET). Nowadays, primary rectal cancers are preferably imaged with transrectal ultrasound or MRI, while barium enema is still the most often used technique for imaging of colonic cancers. Virtual colonoscopy is rapidly evolving and might considerably change the imaging of colorectal cancer in the near future. The use of virtual colonoscopy for screening purposes and imaging of the colon in occlusive cancer or incomplete colonoscopies is currently under evaluation. The main role of PET is in detecting tumour recurrences, both locally and distantly. Techniques to fuse cross-sectional anatomical (computer tomography (CT) and MRI) and functional (PET) images are being developed. Apart from diagnostic imaging, the radiologists has added image-guided minimally invasive treatments of colorectal liver metastases to their arsenal. The radio-frequency ablation technique is now widely available, and can be used during laparotomy or percutaneously in selected cases.

The utility of routine preoperative computed tomography scanning in the management of veterans with colon cancer

BACKGROUND

The aim of this study is to assess the clinical utility of routine preoperative computed tomography (CT) scanning in patients with cancer of the intraperitoneal colon.

METHODS

From November 1997 to June 2001, all patients at VA Puget Sound Healthcare System with a diagnosis of colon cancer were referred for a preoperative CT scan. Medical records and operative notes were reviewed to determine the influence of preoperative CT on clinical management.

RESULTS

Seventy patients received a CT per protocol. Preoperative CT provided information that was used in treatment planning and management in 26 (37%) cases. However, if preoperative scans had not been performed, the clinical management would have been definitively altered in only 13 (19%) patients.

CONCLUSIONS

Although these data suggest potential benefit for routine preoperative CT scanning, we believe additional study, including cost analysis, should precede the adoption of CT scanning as a routine preoperative study in patients with colon cancer.

Radiotherapy and rectal cancer

Pre-operative radiotherapy is being used to reduce local recurrence and improve survival following surgery for rectal cancer. A report by Nagtegaal et al. analyses the histopathological effects in a large, randomized study employing short course radiotherapy. In future, changes in some of these tumour parameters will have to be considered when auditing rectal cancer resections and identifying prognostic factors.

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.

Radiation plus chemotherapy as adjuvant therapy for rectal cancer

The most common neo-adjuvant therapy for rectal cancer is chemotherapy and concurrent radiation therapy. In general, it is delivered pre-operatively for patients with clinical evidence of T(3-4) disease or post-operatively in patients who have undergone surgery and have T(3) and/or N(1-2) disease. This chapter reviews the rationale and results for neo-adjuvant therapy, the selection process for pre-operative versus post-operative treatment, and new approaches and controversies.

Endosonography of anal canal diseases

Anal endosonography became a valuable imaging method for diagnosis of anal diseases because of its accessibility, relative simplicity of performance, and low cost. It is used most often to detect anal sphincter defects, to classify anal fistulas and perianal abscesses, and to stage anal tumors. This review presents a normal anatomy of the anal canal, examination technique, and normal endosonographic anatomy of anal sphincters. The endosonographic findings of anal sepsis, malignancy, trauma, abnormalities in Crohn disease, and ulcerative colitis, as well as the role for anal endosonography among other imaging modalities, are discussed.

Surgery for colorectal cancer

Colorectal cancer remains the second commonest cause of cancer death in North America and Western Europe. Surgery remains the mainstay of treatment. The aim of surgery should be to achieve cure and to avoid locoregional recurrence. The fixity of the primary tumour determines resectability, and the extent of spread determines ultimate survival. Patients with rectal cancer present a particular problem. There is good evidence that lower local recurrence rates may be achieved both by improvements in surgical technique and the use of adjuvant radiotherapy. The importance of adequate treatment of the circumferential tumour margin cannot be over-emphasised; meticulous attention is required to ensure an adequate circumferential excision. The lowest incidences of locoregional recurrence are reported by surgeons who perform total mesorectal excision. Anorectal function, sexual and urinary dysfunction may occur after rectal excision. Both postoperative and pre-operative radiotherapy can reduce the incidence of local recurrence. However, in view of the low recurrence rates obtained with TME alone, the role of adjuvant radiotherapy requires further evaluation. Several aspects of the surgical management of colorectal cancer, for example, the role of transanal local excision of selected rectal cancers and laparoscopic surgery, the management of obstructed cases and the role of follow-up remain to be defined clearly.

Accuracy of magnetic resonance imaging in prediction of tumour-free resection margin in rectal cancer surgery

BACKGROUND

Incomplete surgical removal of the circumferential tumour spread is believed to be the main cause of local recurrence after resection of rectal cancer. This study assessed the accuracy of magnetic resonance imaging (MRI) with a phased-array coil for preoperative staging and prediction of the distance of the tumour from the circumferential resection margin in a total mesorectal excision.

METHODS

76 patients with primary rectal cancer were preoperatively assessed by MRI at 1.5 T, with a phased-array coil. Two observers independently scored, on two occasions, the tumour stage and measured the distance to the mesorectal fascia. Their findings were compared with the final histological findings.

FINDINGS

The MRI tumour stage agreed with the histological stage in 63 (83%) of 76 patients (weighted kappa=0.77 [95% CI 0.66-0.89]) for observer 1, and in 51 (67%) patients (weighted kappa=0.52 [0.37-0.67]) for observer 2. The intraobserver agreement on the tumour stage was good (kappa=0.80 [0.69-0.91]) for observer 1 but moderate (kappa=0.49 [0.34-0.65]) for observer 2. The interobserver agreement was moderate (kappa=0.53 [0.38-0.69]). In 12 patients with an obvious T4 tumour, a margin of 0 mm was correctly predicted. Of 29 patients for whom the pathologist reported a distance of at least 10 mm without specifying the actual distance, a distance of at least 10 mm was predicted in 28 by observer 1 and 27 by observer 2. For the remaining 35 patients, a regression curve was constructed; from this, a histological distance of at least 1.0 mm can be predicted with high confidence when the measured distance on MRI is at least 5.0 mm.

INTERPRETATION

MRI with a phased-array coil showed moderate accuracy and reproducibility for predicting the tumour stage of rectal cancers. The clinically more important circumferential resection margin can, however, be predicted with high accuracy and consistency, allowing preoperative identification of patients at risk of recurrence who will benefit from preoperative radiotherapy, more extensive surgery, or both.

Identification of the fascia propria by magnetic resonance imaging and its relevance to preoperative assessment of rectal cancer

If rectal cancer does not penetrate the fascia propria of the rectum and the rectum is removed with the fascial envelope intact (extrafascial excision), then local recurrence of the cancer will be minimal. Modern imaging techniques have identified a fascial plane surrounding the rectum and mesorectum, and it has been suggested that this is the fascia propria. The aim of this study was to identify whether this plane is the rectal fascia propria and whether tumor invasion through this fascia can be identified preoperatively.

METHODS

Two separate experiments were performed: 1) pelvic magnetic resonance imaging was performed before and after dissection and marking of the plane of extrafascial dissection of the rectum of a cadaver; and 2) magnetic resonance imaging was performed in 43 rectal cancer patients preoperatively. Two radiologists independently reported the depth of tumor invasion in relation to the fascia propria. The tumors were resected by extrafascial excision, and a pathologist independently reported the relation of the tumor to the fascia propria.

RESULTS

The marker inserted in the extrafascial plane showed that the plane visualized on pelvic magnetic resonance imaging was the fascia propria dissected in extrafascial excision of the rectum. The magnetic resonance imaging detected tumor penetration through the fascia propria with a sensitivity of 67 percent, a specificity of 100 percent, and an accuracy of 95 percent.

CONCLUSION

The surgical fascia propria can be identified on preoperative magnetic resonance imaging in patients with rectal cancer. Tumor invasion through this fascia can be detected on magnetic resonance imaging. This method of assessment offers a new way to select those patients who require preoperative radiotherapy.

Local methods of treatment of rectal cancer

Over 11 000 new cases of rectal cancer are reported in the UK each year. Recent technical advances have increased interest in local management of the disease. The introduction of screening for colorectal cancer will potentially lead to an increased number of early rectal cancers suitable for local curative treatment. In addition, as the proportion of elderly patients in the population rises, local methods of treatment of rectal cancer will become increasingly important in this group of patients with comorbid disease. A literature search was performed on Medline database for English language publications on local treatments of rectal carcinoma. Preoperative assessment, selection of patients, local therapeutic and palliative methods of treatment were evaluated. Local methods of treatment can be used for potentially curative operations for rectal cancer. Preoperative endoanal ultrasound appears to be the most useful investigation for determining depth of local invasion. Transanal endoscopic microsurgery has extended the boundaries of local surgery and permits access to the mid and upper rectum with results similar to those of conventional local techniques. Laser therapy and transanal resection provide the best form of palliation for more advanced rectal carcinomas.

Rectal cancer: changing patterns of referral for radiation therapy 1982-1997

BACKGROUND

The purpose of the present study was to evaluate the changing role of radiation therapy in rectal cancer and to determine the patterns of referral of patients during a 15-year period.

METHODS

From 1982 to 1997, 464 patients with carcinoma of the rectum were referred to the Department of Radiation Oncology, Royal Prince Alfred Hospital: 79% of patients had locoregional disease alone and 21% had distant metastasis. Radiation therapy consisted of irradiation (definitive or palliative) alone to the primary tumour in 9.7% of cases; preoperative radiation in 7.3% of cases: preoperative chemoradiation in 7.5% of patients: postoperative radiation in 15.3% of patients: postoperative chemoradiation in 12.31% of patients: treatment of pelvic recurrence in 23.5% of patients and treatment of metastases in 9.1% of patients. The remainder were treated elsewhere (1.9%) or not treated (13.4%).

RESULTS

There was an average annual 14% increase in referrals over the accrual period. Recurrent rectal cancer decreased from approximately 30% of referrals during 1982-91 to approximately 10% in 1995-7. The use of postoperative adjuvant radiation reached a peak of 50% in 1993. The use of preoperative radiation increased suddenly in 1994 from < 10% to a sustained rate of approximately 30% of referrals. The use of chemoradiation commenced in 1990 for postoperative adjuvant treatment and in 1994 for preoperative treatment. The median survival time from initial diagnosis was 35 months, with 2- and 5-year survival rates of 62 and 28%, respectively. Survivals at 5 years for patients treated with preoperative and postoperative radiation (with or without chemotherapy) and with recurrent disease were 56, 44 and 21%, respectively.

CONCLUSIONS

The present study illustrates the changing role of radiation therapy in the management of rectal cancer. The increase in referrals over the observation period was due to increased multidisciplinary input into the initial management of these patients, based on reported clinical trials. The steady increase in the use of adjuvant therapy has paralleled a decrease in referrals for treatment of recurrence and reflects current clinical results. The sequencing of adjuvant therapy is changing currently, with greater emphasis on preoperative adjuvant treatment. Currently most adjuvant therapy includes chemotherapy.

Rectal cancer recurrence: factors and mechanisms

OBJECTIVE

There have been significant developments in treatment for rectal carcinoma, both in surgical and adjuvant therapy. They may however have associated morbidity and hence individualized therapy for rectal cancer is desirable, to optimize treatment but avoid over-treatment for cases where the risk of recurrence is low.

MATERIALS AND METHODS

A literature review was undertaken of the reported incidence of recurrence of rectal carcinoma following curative surgery, factors which predispose to recurrence and proposed mechanisms for recurrence, and the evidence for each critically evaluated.

RESULTS

The incidence of local recurrence of rectal carcinoma following curative resection ranges from 2.6% to 32%, with an average of 15%. Tumour stage is the strongest predictor of tumour recurrence. Upstaging using molecular biology may predict increased risk of recurrence but is not yet proven. Histological factors including differentiation and vascular invasion increase recurrence but are imprecise. Tumour microvascular density and vascular endothelial growth factor (VEGF) levels may be predictive but need refinement. Adequate resection margins are important but recurrence may occur despite this. Tumour cell spillage and distant dissemination may be a mechanism for tumour recurrence following curative resection, but further research is required before this could be applied clinically.

CONCLUSION

Recurrence of rectal cancer remains a significant problem following 'curative' surgery. Multiple factors may influence recurrence risk, though currently however only tumour stage and histological resection margins have demonstrated sufficient importance for management decisions to be made upon them.

Preoperative staging of rectal cancer allows selection of patients for preoperative radiotherapy

BACKGROUND

Variability in rates of local recurrence following resection of rectal cancer has led to the suggestion that all patients should undergo preoperative radiotherapy. This centre employs a selective policy of radiotherapy only in patients with evidence of advanced local disease determined by preoperative staging.

METHODS

A retrospective review was carried out of 114 consecutive patients with rectal cancer. Patients were divided before operation into palliative and curative groups based on preoperative staging. Only patients in the palliative group were offered preoperative radiotherapy. Total mesorectal excision (TME) was performed for all tumours of the middle or lower rectum.

RESULTS

The perioperative mortality rate was 0.9 per cent and anastomotic dehiscence occurred in 2.8 per cent. Local recurrence developed in 4 per cent of patients in the 'curative' group and in seven of 15 of those assigned to the palliative group before operation (P < 0.01). Positive lateral resection margins were significantly associated with a risk of subsequent recurrence (ten of 13 versus three (3 per cent) of 93; P < 0.001).

CONCLUSION

Preoperative adjuvant radiotherapy can be omitted reasonably in patients in whom there is no evidence of locally advanced disease, provided that adequate surgery, incorporating TME for low tumours, is performed.

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.