Preoperative staging of rectal carcinoma

Combination Assessment of Clinical Complete Response of Patients With Rectal Cancer Following Chemoradiotherapy With Endoscopy and Magnetic Resonance Imaging

Purpose

The response to neoadjuvant chemoradiotherapy (CRT) for rectal cancer can be assessed using digital rectal examination, endoscopy and magnetic resonance imaging (MRI). Precise assessment of clinical complete response (CR) after CRT is essential when deciding between optimizing surgery or organ-preserving treatment. The objectives of this study were to correlate the CR finding in endoscopy and MRI with pathologic CR and to determine the appropriate approach for combining endoscopy and MRI to predict the pathologic CR in patients with rectal cancer after neoadjuvant CRT.

Methods

This retrospective cohort study included 102 patients with rectal cancer who underwent endoscopy and MRI at 2–4 weeks after CRT. We assigned a confidence level (1–4) for the endoscopic and MRI assessments. Accuracy, sensitivity, and specificity were analyzed based on the endoscopy, MRI, and combination method findings. Diagnostic modalities were compared using the likelihood ratios.

Results

Of 102 patients, 17 (16.7%) had a CR. The accuracy, sensitivity, and specificity for the prediction CR of endoscopy with biopsy were 85.3%, 52.9%, and 91.8%, while those of MRI were 91.2%, 70.6%, and 95.3%, and those of combined endoscopy and MRI were 89.2%, 52.9%, and 96.5%, respectively. No significant differences were noted in the sensitivity and specificity of any each modality. The prediction rate for CR of the combination method was 92.6% after the posttest probability test.

Conclusion

Our study demonstrated that combining the interpretation of endoscopy with biopsy and MRI could provide a good prediction rate for CR in patients with rectal cancer after CRT.

Proteomics analysis of differential protein expression identifies heat shock protein 47 as a predictive marker for lymph node metastasis in patients with colorectal cancer

The discovery of biomarkers to predict the potential for lymph node (LN) metastasis in patients with colorectal cancer (CRC) is essential for developing improved strategies for treating CRC. In the present study, they used isobaric tags for relative and absolute quantitation to conduct a proteomic analysis designed to identify novel biomarkers for predicting LN metastasis in patients with CRC. They identified 60 differentially expressed proteins specifically associated with LN metastasis in CRC patients and classified the molecular and functional characteristics of these proteins by bioinformatic approaches. A literature search led them to select heat shock protein 47 (HSP47) as the most suitable candidate biomarker for predicting LN metastasis. Validation analysis by immunohistochemistry showed that HSP47 expression in patients with CRC and the number of HSP47-positive spindle cells in the tumor stroma were significantly higher compared with those in adjacent normal colonic mucosa, and the number of the latter cells increased with tumor progression. Further, the number of HSP47-positive spindle cells in stroma was a more informative marker for identifying LN metastasis than HSP47expression. Multivariate analysis identified spindle cells that expressed elevated levels of HSP47 as an independent predictive biomarker for CRC with LN metastasis. Moreover, these cells served as an independent marker of disease-free and overall survival of patients with CRC. Their data indicate that the number of HSP47-positive spindle cells in the stroma of CRC may serve as a novel predictive biomarker of LN metastasis, early recurrence and poor prognosis.

Dual-Energy CT of Rectal Cancer Specimens: A CT-based Method for Mesorectal Lymph Node Characterization

BACKGROUND

An accurate method to assess malignant lymph nodes in the mesorectum is needed. Dual-energy CT scans simultaneously with 2 levels of energy and thereby provides information about tissue composition based on the known effective Z value of different tissues. Each point investigated is represented by a certain effective Z value, which allows for information on its composition.

OBJECTIVE

We wanted to standardize a method for dual-energy scanning of rectal specimens to evaluate the sensitivity and specificity of benign versus malignant lymph node differentiation. Histopathological evaluation of the nodes was our reference.

DESIGN

This was a descriptive and prospective study.

SETTINGS

Seventeen rectal specimens were examined in 2 series. The first series was conducted with 3 specimens from patients who were not given perioperative contrast; 3 had iodine-based contrast and 3 had gadolinium-based contrast. We concluded that iodine was the contrast agent of choice and therefore included 8 more patients in a second series, given iodine-based contrast, for further analysis.

PATIENTS

Quantitative imaging data were collected from 197 individual lymph nodes from 17 specimens, from patients with rectal cancer.

MAIN OUTCOME MEASURES

We measured accuracy of differentiating benign from malignant lymph nodes by investigating the following: 1) gadolinium, iodine, and water concentrations in lymph nodes; 2) dual-energy ratio; 3) dual-energy index; and 4) effective Z value.

RESULTS

Optimal discriminations between benign and malignant lymph nodes were obtained using the following cutoff values: 1) effective Z at 7.58 (sensitivity, 100%; specificity, 90%; and accuracy, 93%), 2) dual-energy ratio at 1.0 × 10 (sensitivity, 96%; specificity, 87%; and accuracy, 90%), 3) dual-energy index at 0.03 (sensitivity, 97%; specificity, 88%; and accuracy, 91%), and 4) iodine concentration at 2.58 μg/mL (sensitivity, 86%; specificity, 92%; and accuracy, 89%).

LIMITATIONS

The investigation is conducted on isolated surgical specimens from rectal cancer operations.

CONCLUSIONS

Dual-energy CT can be performed on rectal specimens. The discrimination between benign and malignant nodes seems promising when using iodine as contrast.

Rectal cancer staging: Multidetector-row computed tomography diagnostic accuracy in assessment of mesorectal fascia invasion

AIM: To assess the diagnostic accuracy of multidetector-row computed tomography (MDCT) as compared with conventional magnetic resonance imaging (MRI), in identifying mesorectal fascia (MRF) invasion in rectal cancer patients.

METHODS: Ninety-one patients with biopsy proven rectal adenocarcinoma referred for thoracic and abdominal CT staging were enrolled in this study. The contrast-enhanced MDCT scans were performed on a 256 row scanner (ICT, Philips) with the following acquisition parameters: tube voltage 120 KV, tube current 150-300 mAs. Imaging data were reviewed as axial and as multiplanar reconstructions (MPRs) images along the rectal tumor axis. MRI study, performed on 1.5 T with dedicated phased array multicoil, included multiplanar T2 and axial T1 sequences and diffusion weighted images (DWI). Axial and MPR CT images independently were compared to MRI and MRF involvement was determined. Diagnostic accuracy of both modalities was compared and statistically analyzed.

RESULTS: According to MRI, the MRF was involved in 51 patients and not involved in 40 patients. DWI allowed to recognize the tumor as a focal mass with high signal intensity on high b-value images, compared with the signal of the normal adjacent rectal wall or with the lower tissue signal intensity background. The number of patients correctly staged by the native axial CT images was 71 out of 91 (41 with involved MRF; 30 with not involved MRF), while by using the MPR 80 patients were correctly staged (45 with involved MRF; 35 with not involved MRF). Local tumor staging suggested by MDCT agreed with those of MRI, obtaining for CT axial images sensitivity and specificity of 80.4% and 75%, positive predictive value (PPV) 80.4%, negative predictive value (NPV) 75% and accuracy 78%; while performing MPR the sensitivity and specificity increased to 88% and 87.5%, PPV was 90%, NPV 85.36% and accuracy 88%. MPR images showed higher diagnostic accuracy, in terms of MRF involvement, than native axial images, as compared to the reference magnetic resonance images. The difference in accuracy was statistically significant (P = 0.02).

CONCLUSION: New generation CT scanner, using high resolution MPR images, represents a reliable diagnostic tool in assessment of loco-regional and whole body staging of advanced rectal cancer, especially in patients with MRI contraindications.

Reliability of (18)f-fluorodeoxyglucose positron emission tomography/computed tomography in the nodal staging of colorectal cancer patients

Purpose

Lymph-node metastasis is considered as critical prognostic factor in colorectal cancer. A preoperative evaluation of lymph-node metastasis can also help to determine the range of distant lymph node dissection. However, the reliability of ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) in the detection of lymph-node metastasis is not fully known.

Methods

The medical records of 433 patients diagnosed with colorectal cancer were reviewed retrospectively. FDG-PET/CT and CT were performed on all patients. Lymph nodes were classified into regional and distant lymph nodes according to the American Joint Committee on Cancer (AJCC) Cancer Staging Manual, 7th edition.

Results

The patients included 231 males (53.3%) and 202 females (46.7%), with a mean age of 64.7 ± 19.0 years. For regional lymph nodes, the sensitivity of FDG-PET/CT was lower than that of CT (57.1% vs. 73.5%, P < 0.001). For distant lymph nodes, the sensitivity of FDG-PET/CT was higher than that of CT (64.7% vs. 52.9%, P = 0.012). The sensitivity of FDG-PET/CT for regional lymph nodes was higher in patients with larger primary tumors. The positivity of lymph-node metastasis for FDG-PET/CT was affected by carcinoembryonic antigen levels, tumor location, and cancer stage for regional lymph nodes and by age and cancer stage for distant lymph nodes (P < 0.05).

Conclusion

The sensitivity of FDG-PET/CT for regional lymph-node metastasis was not superior to that of CT. However, FDG-PET/CT provides helpful information for determining surgical plan especially in high risk patients group.

Association between surgeon characteristics and their preferences for guideline-concordant staging and treatment for rectal cancer

BACKGROUND

Rectal cancer guidelines recommend transrectal ultrasound or magnetic resonance imaging for locoregional staging and neoadjuvant chemoradiation therapy (CRT) for Stage II/III disease, but studies show these are underutilized. We examined how surgeon preferences align with guidelines or vary by training.

METHODS

Questionnaires on training, years of practice, and staging/treatment preferences were sent to surgeons practicing in Florida.

RESULTS

Of 759 surveys distributed, 321 (42%) responded; 158 were excluded because they were trainees, not treating rectal cancer, or not board certified/eligible. Among the remaining 163, 71% were general surgeons, 18% colorectal surgeons, and 11% surgical oncologists. Colorectal surgeons and surgical oncologists were more likely than general surgeons to prefer transrectal ultrasound/magnetic resonance imaging (79% vs 50%; P < .01), and neoadjuvant CRT (71% vs 45%; P < .01). Differences remained significant after adjusting for years in practice.

CONCLUSION

Increased focus on appropriate use of staging procedures and neoadjuvant CRT within general surgery training/educational programs is warranted.

Clinical review: surgical management of locally advanced and recurrent colorectal cancer

AIM

Recurrent and locally advanced colorectal cancers frequently require en bloc resection of involved organs to achieve negative margins. The aim of this review is to evaluate the most current literature related to the surgical management of locally advanced and recurrent colorectal cancer.

METHODS

A literature review was performed on the electronic databases MEDLINE from PubMed, EMBASE and the Cochrane library for publications in the English language from January 1993 to July 2013. The MeSH search terms 'locally advanced colorectal cancer', 'recurrent colorectal cancer' and 'surgical management' were used.

RESULTS

A total of 1,470 patients with recurrent or locally advanced primary colorectal cancer were included in 22 studies. Surgical removal of the tumour with negative margins (R0) offers the best prognosis in term of survival with a 5-year survival of up to 70 %. MVR is needed in approximately 10 % with the most commonly involved organ being the bladder. The mean post-operative morbidity is 40 %, mainly relating to superficial surgical site infection, pelvic collections and delayed wound healing. Most patients will undergo radiotherapy and/or chemotherapy pre- or post-operatively. The mean 5-year overall survival for R0 resection is 50 % for recurrent and locally advanced primary tumours while survival following R1 or R2 is 12 and <5 %, respectively.

CONCLUSION

Multimodal therapy and extended surgery to achieve clear margins offers good prognosis to patients with recurrent and locally advanced colorectal cancers.

Evaluation of the growth pattern of carcinoma of colon and rectum by MDCT

BACKGROUND

Colorectal cancer is a leading cause of cancer morbidity and mortality worldwide. Knowledge of colorectal cancer tumor growth is of importance for basic understanding of tumor biology and for the clinical handling of the disease.

PURPOSE

To conduct a retrospective evaluation of the growth pattern of colorectal cancer by multidetector computed tomography (MDCT).

MATERIAL AND METHODS

Pathologically proven adenocarcinomas of the colon and rectum in 44 patients were examined by MDCT on at least two separate occasions with an interval of >1 month in patients not receiving therapy. Maximal longitudinal diameters, wall thicknesses, and volume changes, as determined by serial CT scans, were used in calculation of growth rates.

RESULTS

Mean longitudinal diameters of tumors at initial and follow-up investigations were 3.8 cm (1.0-9.1 cm) and 5.4 cm (2.5-12.2 cm), respectively. The mean growth rate of longitudinal tumor diameter was 3.4 cm/year (0-13.8 cm/year). Mean axial wall thicknesses at initial and follow-up investigations were 1.4 cm (0.6-6.6 cm) and 1.9 cm (0.8-6.8 cm), respectively. Mean growth rate of tumor axial wall thickness was 1.0 cm/year (0-3.1 cm/year). Mean tumor volumes at initial and follow-up investigations were 1975 cm(3) (172-9756 cm(3); median, 1490) and 3545 cm(3) (442-15211 cm(3); median, 2846), respectively. Mean growth rate of tumor volume was 2912 cm(3)/year (216-12548 cm(3)/year; median, 1698), and volume doubling times varied from 0.05 to 7.1 years (mean, 1.2; median, 0.7). Significant correlations were observed between initial wall thickness and volume growth rate (p = 0.004). No significant difference was observed between other initial tumor size and growth rate.

CONCLUSION

The tumor growth doubling time of colorectal cancer has a very broad aspect. The initial wall thickness of the tumor on MDCT appears to be the most powerful parameter showing correlation with the volume growth rate.

Diagnostic value of FDG-PET/CT for lymph node metastasis of colorectal cancer

BACKGROUND

Lymph node metastasis is an important prognostic factor in patients with colorectal cancer. We assessed the ability of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) to diagnose lymph node metastases in colorectal cancer patients.

METHODS

We retrospectively analyzed the records of 473 patients who underwent preoperative FDG-PET/CT, followed by curative surgery for colorectal cancer. Lymph node metastases were assessed as proximal or distal, depending on their anatomical location. We analyzed the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of FDG-PET/CT and CT for detecting lymph node metastases.

RESULTS

In detecting proximal lymph nodes, FDG-PET/CT had a sensitivity of 66 %, a specificity of 60 %, a PPV of 63 %, an NPV of 62 %, and an accuracy of 63 %; whereas CT had a sensitivity of 87 %, a specificity of 29 %, a PPV of 57 %, an NPV of 68 %, and an accuracy of 59 % (P = 0.245). FDG-PET/CT and CT also showed similar accuracy in detecting distal lymph nodes (87 vs. 88 %, P = 0.620).

CONCLUSION

Preoperative FDG-PET/CT and CT have comparable accuracy in detecting lymph node metastases of colorectal cancer.

Can we predict pathologic complete response before surgery for locally advanced rectal cancer treated with preoperative chemoradiation therapy?

BACKGROUND

Pathologic complete response has been proven to have oncological benefits for locally advanced rectal cancer treated with chemoradiation therapy. The aims of this study are to analyze and determine the factors to predict pathologic complete response for patients treated with preoperative neoadjuvant therapy.

METHODS

Patients with biopsy-proven, locally advanced rectal cancer were treated neoadjuvantly followed by radical surgical resection. Tumors were re-assessed after completing chemoradiation, including pelvic magnetic resonance images, colonoscopic examination, and re-biopsy. The results of examination were compared with the final pathologic status.

RESULTS

A retrospective chart review of 166 patients was conducted. Twenty-five patients (15.1%) had pathologic complete response after chemoradiation. The 5-year overall survival rates were better in the complete response group than the residual tumor group (91.1% vs. 70.8%; P = 0.047), and there were also significant differences in the 5-year disease-free survival rates between these two groups (91.1% vs. 70.2%; P = 0.027). The prediction rates for pathologic complete response by re-biopsy, magnetic resonance images, and colonoscopy were 21.4%, 33.3%, and 53.8%, respectively. In addition, when we further combine the results of colonoscopic findings and re-biopsy, the prediction rate for pathologic complete response reached 77.8% (P = 0.009).

CONCLUSIONS

Combining the results of the re-biopsy and post-treatment colonoscopic findings, we can achieve a good prediction rate for pathologic complete response. Post-treatment magnetic resonance images are not useful tools in predicting tumor clearance following chemoradiation.

Rectal cancer staging

Rectal cancer staging provides critical information concerning the extent of the disease. The information gained from staging is used to determine prognosis, to guide management, and to assess response to therapy. Accurate staging is essential for directing the multidisciplinary approach to therapy. This article focuses on the evolution of staging systems, the rational for staging, and current methods used to stage rectal cancer.

Regional lymph node metastasis and locoregional recurrence of rectal carcinoma in the era of TME [corrected] surgery. Implications for treatment decisions

BACKGROUND AND AIMS

For rectal carcinoma treated according to the concept of total mesorectal excision (TME surgery), the independent influence of regional lymph node metastasis on the locoregional recurrence risk is still in discussion. A reliable assessment of this risk is important for an individualised selective indication for neoadjuvant radio-/radiochemotherapy.

METHODS

Analysis of literature, especially of the last 20 years, and consideration of pathological and oncological basic research. Multivariate analysis of data of the Erlangen Registry of Colorectal Carcinoma.

RESULTS

The clinical assessment of the pretherapeutic regional lymph node status by the present available imaging methods is still unreliable. The analysis of the association between pretherapeutic regional lymph node status and locoregional recurrence risk has to be based on follow-up data of patients treated by primary surgery and has to be distinguished between patients treated by conventional and optimised quality-assured TME surgery, respectively. Data from Erlangen show an increase of the local recurrence risk for patients with at least four involved regional lymph nodes.

CONCLUSIONS

For patients with at least four involved regional lymph nodes, a neoadjuvant radiochemotherapy may be indicated. However, today, the pretherapeutic diagnosis is uncertain and results in overtherapy in 40%. Thus, in case of positive lymph node findings by imaging methods, the benefits and risk of neoadjuvant therapy in such situations should always be discussed with the patient in the sense of informed consent and shared decision.

Transrectal ultrasonography in preoperative staging of rectal carcinoma: diagnostic value and relationship with TNM staging

AIM: To investigate the diagnostic value of transrectal ultrasonography (TRUS) in preoperative staging of rectal carcinoma and the relationship between TRUS and TNM staging.

METHODS: Sixty-five patients with pathologically confirmed rectal carcinoma were detected by TRUS before surgery. The circumference of the bowel wall involved by tumor was recorded. The preoperative transrectal ultrasonographic staging of rectal carcinoma was performed using the TNM staging system. The preoperative staging results were then compared with those of postoperative pathologic staging.

RESULTS: The overall accuracy rate of preoperative staging of rectal carcinoma by TRUS was 86.15%. The diagnostic accuracy in T₁-T₄-stage patients by TRUS was 93.85%, 87.69%, 90.77% and 100%, respectively. The circumference of the bowel wall involved by tumor was positively correlated with pathological tumor stage (r = 0.89, P < 0.01). The overall accuracy rate of preoperative staging of rectal carcinoma by TRUS in combination with the circumference of the bowel wall involved by tumor was 95.38%.

CONCLUSION: TRUS has a high diagnostic accuracy in preoperative staging of rectal carcinoma. TRUS in combination with the circumference of the bowel wall involved by tumor can improve the diagnostic accuracy of preoperative staging of rectal carcinoma.

Endoscopic ultrasound and magnetic resonance imaging for re-staging rectal cancer after radiotherapy

AIM: To compare the sensitivity and specificity of two imaging techniques, endoscopic ultrasound (EUS) and magnetic resonance imaging (MRI), in patients with rectal cancer after neoadjuvant chemoradiation therapy. And we compared EUS and MRI data with histological findings from surgical specimens.

METHODS: Thirty-nine consecutive patients (51.3% Male; mean age: 68.2 ± 8.9 years) with histologically confirmed distal rectal cancer were examined for staging. All patients underwent EUS and MRI imaging before and after neoadjuvant chemoradiation therapy.

RESULTS: After neoadjuvant chemoradiation, EUS and MRI correctly classified 46% (18/39) and 44% (17/39) of patients, respectively, in line with their histological T stage (P > 0.05). These proportions were higher for both techniques when nodal involvement was considered: 69% (27/39) and 62% (24/39). When patients were sorted into T and N subgroups, the diagnostic accuracy of EUS was better than MRI for patients with T0-T2 (44% vs 33%, P > 0.05) and N0 disease (87% vs 52%, P = 0.013). However, MRI was more accurate than EUS in T and N staging for patients with more advanced disease after radiotherapy, though these differences did not reach statistical significance.

CONCLUSION: EUS and MRI are accurate imaging techniques for staging rectal cancer. However, after neoadjuvant RT-CT, the role of both methods in the assessment of residual rectal tumors remains uncertain.

Preoperative investigations for metastatic staging of colon and rectal cancer across multiple centres--what is current practice?

OBJECTIVE

The optimal strategy for elective distant staging of colorectal carcinoma (CRC) has yet to be defined, with current guidelines based on small and limited series. One specific issue requiring review is the value of routine computerized tomographic (CT) chest examination. Also lacking is data on current routine clinical practice.

METHOD

A retrospective chart review of consecutive cases of elective surgery for CRC from five hospitals.

RESULTS

Two hundred and fifty-seven cases were reviewed, 128 colon and 129 rectal primaries. 164 (64%) of patients overall, ranging from 45% to 88% across the individual centres, had a preoperative serum CEA level performed. CT abdomen/pelvis was performed in 222 (86%) of cases, ranging from 69% to 98% per centre. CT chest was performed in 95 (37%) of cases, 47% of rectal vs 29% of colon cancers (P = 0.004). In 17 cases (18%) CT chest examinations revealed abnormalities suspicious for metastatic disease, leading to a change in management in six (35%) of these cases. Of the 17 cases with an abnormal CT chest, in only 5 of the 14 (36%) where carcinoembryonic antigen (CEA) levels were also recorded was this increased, and in only three (21%) was this markedly (> 10 microg/l) elevated.

CONCLUSIONS

Substantial variability exists in the preoperative evaluation of patients with CRC. Many patients do not have a CEA and/or abdominal imaging performed. Where performed, CT chest revealed suspicious findings in a significant number of patients, the vast majority of whom had a normal or near normal CEA. Future studies are required to define optimal preoperative staging.

Role of PET/CT in the detection of liver metastases from colorectal cancer

PURPOSE

The aim of this study was to compare the diagnostic accuracy of 2-[fluorine-18] fluoro-2-deoxy-D-glucose positron emission tomography (18F-FDG-PET) and computed tomography (CT) with PET/CT in the detection of liver metastases during tumour staging in patients suffering from colorectal carcinoma for the purposes of correct surgical planning and follow-up.

MATERIALS AND METHODS

A total of 467 patients underwent a PET/CT scan using an iodinated contrast medium. We compared images obtained by the single PET scan, the single CT scan and by the fusion of the two procedures (PET/CT). The final diagnosis was obtained by histological examination and/or by the follow-up of all patients, including those who did not undergo surgery or biopsy.

RESULTS

The PET scan had 94.05% sensitivity, 91.60% specificity and 93.36% accuracy; the CT scan had 91.07% sensitivity, 95.42% specificity and 92.29% accuracy. The combined procedures (PET/CT) had the following values: sensitivity 97.92%, specificity 97.71% and accuracy 97.86%.

CONCLUSIONS

This study indicates that PET/CT is very useful in staging and restaging patients suffering from colorectal cancer. It was particularly useful when recurrences could not be visualised either clinically or by imaging despite increasing tumour markers, as it guaranteed an earlier diagnosis. PET/CT not only provides high diagnostic performance in terms of sensitivity and specificity, enabling modification of patient treatment, but it is also a unique, high-profile procedure that can produce cost savings.

Rectal villous tumours: MR features and correlation with TRUS in the preoperative evaluation

AIM

The aim of this study was to assess the clinical relevance of MR and transrectal ultrasonography (TRUS) imaging of rectal villous tumours to elucidate the correlation between imaging results and specific histopathological tumour features, such as tumour size (T) and lymph node involvement (N), in order to establish the better technique for the pre-surgical patient evaluation.

PATIENTS AND METHODS

23 cases of villous tumours of the rectum were studied with phased-array MR and TRUS. All patients underwent either surgical or endoscopic treatment. Final diagnosis was based on histopathological results. In particular, the following features were characterized by the imaging techniques mentioned above: lesion site, distance between lesion and ano-rectal junction, size, morphology and contrast enhancement of lesions, fluid layer around the lesion, alterations of the deep layers of the rectal wall, sphincter infiltration, presence or absence of mesorectal, iliac and obturatory lymphnode involvement.

RESULTS

Histology established muscular involvement in 7 cases (T2), perirectal fat infiltration in 1 case (T3); in the remaining 15 cases, staging was Tis-T1. In 17/23 cases (73.9%) the lesions were correctly staged with both imaging techniques, whereas in 5/23 cases (21.7%) the lesions were overstaged. No cases were understaged. TRUS concorded with histological exams in 17/23 cases (73.9%). 5/23 cases (21.7%) were overstaged and 1/23 (4%) was understaged. MR and TRUS were in accordance in 20/23 cases (86.9%).

DISCUSSION

Considering the frequent degeneration of villous tumours, correct preoperative identification and precise evaluation of these lesions, such as the detection of rectal wall invasion, is essential in deciding optimal treatment strategy. MRI and TRUS allow the identification of specific features of villous tumours and of malignant degeneration, allowing for a correct local disease staging.

Relationship between Transrectal color and power Doppler ultrasonography quantification and TNM staging in rectal cancer

AIM: To reveal the relations of the parameters in color Doppler flow imaging (CDFI) and power Doppler imaging (PDI) with TNM staging in rectal cancer.

METHODS: Transrectal color and power Doppler ultrasound examinations were performed on 86 patients with rectal cancer before surgery. Tumor blood flow signals were recorded including peak stream velocity (PSV) and resistance index (RI) and calculated vascularity index (VI). All the rectal cancers were staged by TNM system.

RESULTS: There was a significant correlation between VI and TNM staging (χ² = 32.78, P < 0.05), but PSV and RI had no correlation with TNM staging in rectal cancer (χ² = 2.942, 4.473, P = 0.816, 0.613).

CONCLUSION: VI can be used in the evaluation of rectal cancer angiogenesis before operation, and also may provide valuable information for preoperative diagnosis and prognosis evaluation.

The impact of 18-fluorodeoxyglucose positron emission tomography-computed tomography on the staging and management of primary rectal cancer

PURPOSE

18-Fluorodeoxyglucose positron emission tomography-computed tomography (FDG PET-CT) has a role in recurrent colorectal cancer. This study was designed to assess the impact of PET-CT on management of primary rectal cancer.

METHODS

Eighty-three patients with rectal cancer underwent PET-CT scan between 2002 and 2005. Referring physicians prospectively recorded stage and management plan after conventional imaging before PET-CT scan, which were compared to subsequent stage and management after PET-CT.

RESULTS

Staging PET-CT caused a change in stage from conventional imaging in 26 patients (31 percent). Twelve (14 percent) were upstaged (7 change in N stage; 4 change in M stage; 1 change in N and M stage), and 14 (17 percent) were downstaged (10 change in N stage; 3 change in M stage; 1 change in N and M stage). PET-CT scan altered management intent in seven patients (8 percent) (curative to palliative 6 patients; palliative to curative 1 patient). Management was altered in ten patients (12 percent). There was no difference in impact with respect to tumor height.

CONCLUSIONS

PET-CT scan impacts the management of patients with primary rectal cancer and influences staging/therapy in a third of patients and should be a component of rectal cancer workup.

Comparison of CT and MRI for presurgical characterization of paraaortic lymph nodes in patients with pancreatico-biliary carcinoma

AIM: To determine the accuracy of computed tomography (CT) and magnetic resonance (MR) for presurgical characterization of paraaortic lymph nodes in patients with pancreatico-biliary carcinoma.

METHODS: Two radiologists independently evaluated CT and MR imaging of 31 patients who had undergone lymphadenectomy (9 metastatic and 22 non-metastatic paraaortic nodes). Receiver operating characteristic (ROC) curve analysis was performed using a five point scale to compare CT with MRI. To re-define the morphologic features of metastatic nodes, we evaluated CT scans from 70 patients with 23 metastatic paraaortic nodes and 47 non-metastatic ones. The short axis diameter, ratio of the short to long axis, shape, and presence of necrosis were compared between metastatic and non-metastatic nodes by independent samples t-test and Fisher’s exact test. P < 0.05 was considered statistically significant.

RESULTS: The mean area under the ROC curve for CT (0.732 and 0.646, respectively) was slightly higher than that for MRI (0.725 and 0.598, respectively) without statistical significance (P = 0.940 and 0.716, respectively). The short axis diameter of the metastatic lymph nodes (mean = 9.2 mm) was significantly larger than that of non-metastatic ones (mean = 5.17 mm, P < 0.05). Metastatic nodes had more irregular margins (44.4%) and central necrosis (22.2%) than non-metastatic ones (9% and 0%, respectively), with statistical significance (P < 0.05).

CONCLUSION: The accuracy of CT scan for the characterization of paraaortic nodes is not different from that of MRI. A short axis-diameter (> 5.3 mm), irregular margin, and presence of central necrosis are the suggestive morphologic features of metastatic paraaortic nodes.

Preoperative staging of rectal tumors: comparison of endorectal ultrasound, hydro-CT, and high-resolution endorectal MRI

AIM

The aim of this study was to compare transrectal ultra-sound (TRUS), hydro-computed tomography (hydro-CT), and endorectal magnetic resonance imaging (MRI) in the preoperative staging of rectal cancer.

PATIENTS AND METHODS

23 patients with rectal adenocarcinoma underwent TRUS, hydro-CT, and MRI (1 Tesla) with endorectal coil. The results were correlated with the histopathological findings based on the TNM classification.

RESULTS

T staging with TRUS, hydro-CT, and endorectal MRI correlated with the histopa-thological findings in 83% of patients (19/23). Tumors were overestimated by TRUS in 2/23 patients, by CT in 3/23, and by MRI in 3/23 patients. Tumor size was underestimated by TRUS in 2 patients, by CT and MRI in 1 case each. Local lymphatic node involvement was correctly diagnosed with CT and MRI in 87% and 83%, respectively. Using TRUS, false-negative results in the staging of lymph node involvement were seen in 3/23 patients, whereas 1 patient was over-staged. Using hydro-CT as well as endorectal MRI, overstaging of the local lymph nodes took place in 2/23 patients.

CONCLUSION

All methods are limited because peritumoral inflammation cannot be precisely distinguished from infiltration by the tumor. Correct lymph node staging is hampered in advanced disease using TRUS. In these patients, further cross-sectional imaging may be required.

The role of radiation therapy for colorectal cancer

Radiation therapy (RT) has been used to treat cancers for more than a century. Recent randomized trials have helped clarify the treatment recommendations in the use of RT for colorectal cancers. This article reviews these trials to illustrate key concepts, places these trials in perspective, and provides direction for future research.

Local excision and endoscopic posterior mesorectal resection versus low anterior resection in T1 rectal cancer

Background

Rectum-preserving endoscopic posterior mesorectal resection (EPMR) removes the local lymph nodes in a minimally invasive manner and completes tumour staging after transanal local excision (TE). The aim of this study was to compare the morbidity and mortality of TE and EPMR with those of low anterior resection (LAR) in patients with T1 rectal cancer.

Methods

Between 1996 and 2006 EPMR was performed 6 weeks after TE in 18 consecutive patients with a T1 rectal cancer. Morbidity and mortality were recorded prospectively and compared with those in a group of 17 patients treated by LAR. Lymph node involvement and local recurrence rate were analysed in both groups.

Results

Two major and three minor complications were noted after EPMR, and four major and four minor complications after LAR (P = 0·402 for major and P = 0·691 for minor complications). Median number of lymph nodes removed was 7 (range 1–22) for EPMR and 11 (range 2–36) for LAR (P = 0·132). Two of 25 patients with a low-risk rectal cancer were node positive. No patient developed locoregional recurrence.

Conclusion

EPMR after TE is a safe option for T1 rectal cancer. This two-stage procedure has a lower morbidity than LAR and may reduce locoregional recurrence compared with TE alone.

Imaging and management of rectal cancer

Local staging and management of rectal cancer has evolved during the past decade. Imaging modalities used for staging rectal cancer include CT, endoscopic ultrasound, pelvic phased-array coil MRI, endorectal MRI, and PET. Each modality has its strengths and limitations. Evidence supports the use of both endoscopic ultrasound and CT in staging rectal cancer. MRI is the only reliable tool for determining the status of the circumferential resection margin, which is important for the assessment of the risk of local recurrence.

Preoperative 3T MR imaging of rectal cancer: local staging accuracy using a two-dimensional and three-dimensional T2-weighted turbo spin echo sequence

PURPOSE

The purpose of our study was to evaluate the image quality and diagnostic performance of two-dimensional (D) turbo spin echo (TSE) and 3D T2-weighted TSE MR imaging in local staging of rectal cancer at 3T.

MATERIALS AND METHODS

3T phased-array MR imaging was performed in 36 consecutive patients with biopsy-proven rectal cancer. High-resolution 2D TSE images in three planes and 3D TSE images of the rectum were obtained. Two independent observers performed an image quality assessment using eight image quality characteristics. All 2D and 3D datasets were evaluated separately. MR images were prospectively evaluated by two experienced radiologists in consensus with regard to local disease. Total mesorectal excision was used as the standard of reference. The sensitivity, specificity, positive and negative predictive value, and overall accuracy were calculated. Areas under the receiver operating characteristic (ROC) curve (AUC) were determined.

RESULTS

Twenty-two patients who underwent a total mesorectal excision were enrolled in this study. Significantly more motion artifacts were present with 3D TSE imaging (P=0.04). The overall sensitivity, specificity, and accuracy of muscularis propria invasion in rectal cancer using 2D T2-weighted images were 100%, 66%, and 95%, respectively. There was a statistical significant greater AUC using 2D T2-weighted images compared to 3D T2-weighted MR images (P=0.04). The ROC curves describing the results of the interpretation of 2D and 3D T2-weighted datasets regarding perirectal tissue invasion showed no statistical significant difference (P=0.41).

CONCLUSIONS

In this study, high local staging accuracies with 3T 2D T2-weighted MR imaging were demonstrated. 3D T2-weighted MR imaging cannot replace 2D MR imaging for local staging of rectal cancer. However, 3D MR imaging can be used for visualization of the complex pelvic anatomy for treatment planning purposes.

Effect of using endorectal coil in preoperative staging of rectal carcinomas by pelvic MR imaging

PURPOSE

To assess the accuracy of magnetic resonance imaging with pelvic phased-array and endorectal coils prospectively, and evaluate if endorectal coil provides any additional information to high resolution pelvic MR imaging in rectal carcinoma staging.

MATERIALS AND METHODS

Preoperative MRI of 25 patients with rectal carcinoma was performed with pelvic phased-array coil alone, and with both phased-array coil and endorectal coil placed. Staging was made by evaluating images obtained by using both coils prospectively, and correlated with histopathologic staging. The images were then assessed separately, and compared to each other retrospectively.

RESULTS

Two and 3 of the 5 histopathologically proved T1 tumors were staged correctly on MRI with pelvic phased-array coil alone and after the endorectal coil placement, respectively. Histopathologically identified five T2 tumors were staged correctly as T2 in 4 of the cases, 1 was understaged and 10 of 14 patients who had T3 tumor were staged as T3, 4 of them were understaged as T2 on both techniques. Specificity, sensitivity and accuracy rates for staging of T3 tumors were found as 71%, 100% and 84%, respectively, for each technique. Sensitivity and positive predictive value of N staging were both 88% on both techniques.

CONCLUSION

Pelvic MR imaging after the placement of endorectal coil in addition to the phase-array coil was not superior to the imaging with phased-array coil alone in T staging of rectal carcinomas and the latter achieved better visualization of the lymph nodes by means of larger field of view.

Is the increasing rate of local excision for stage I rectal cancer in the United States justified?: a nationwide cohort study from the National Cancer Database

OBJECTIVE

Determine rates of local excision (LE) over time, and test the hypothesis that LE carries increased oncologic risks but reduced perioperative morbidity when compared with standard resection (SR).

SUMMARY BACKGROUND DATA

Despite the lack of level I/level II evidence supporting its oncologic adequacy, LE is performed for stage I rectal cancer.

METHODS

Surgical therapy for 35,179 patients with stage I rectal cancer diagnosed in 1989 to 2003 was examined over time, utilizing the National Cancer Database. A special study then analyzed perioperative outcomes, local recurrence and survival in 2124 patients diagnosed between 1994 and 1996, including 765 (T1, 601; T2, 164) treated by LE and 1359 (T1, 493; T2, 866) treated by SR.

RESULTS

From 1989 to 2003, the use of LE has increased (T1, 26.6-43.7%; T2, 5.8-16.8%; P < 0.001 both). The special study demonstrated significantly lower 30-day morbidity after LE versus SR (5.6% vs. 14.6%; P < 0.001). After adjusting for patient and tumor characteristics, the 5-year local recurrence after LE versus SR was 12.5 versus 6.9% (P = 0.003; hazard ratio = 0.38; 95% CI, 0.23-0.62) for T1 tumors, and 22.1 versus 15.1% (P = 0.01; hazard ratio = 0.69; 95% CI, 0.44-1.07) for T2 tumors. The 5-year overall survival (T1, 77.4% vs. 81.7%, P = 0.09; T2, 67.6% vs. 76.5%, P = 0.01) was influenced by age and comorbidities but not the type of surgery.

CONCLUSIONS

This study provides the best evidence for both the increasing use and the associated risks of LE versus SR. For each individual patient, the benefits of LE must be balanced against the heightened risk of local failure.

Accurate staging, selective preoperative therapy and optimal surgery improves outcome in rectal cancer: a review of the recent evidence

OBJECTIVE

The current optimal management of locally advanced rectal cancer has evolved from surgical excision followed by postoperative therapy in patients with involved margins, to an increasing use of a preoperative strategy to 'down-stage and/or down-size' the tumour. This treatment strategy is based on the relationship of the tumour to the mesorectal fascia, the optimal surgical circumferential resection margin that can be achieved by total mesorectal excision. We have reviewed the recent evidence for this strategy.

METHOD

An electronic literature search using PubMed identified articles on the subject of rectal cancer between January 2000 and December 2005. The search was limited to English language publications with secondary references obtained from key articles. Articles published in high impact factor journals formed the basis of the review, together with articles related to national programmes on the management of rectal cancer. This does lead to a selection bias, particularly as the articles identified had a European bias.

CONCLUSION

The UK NHS Cancer Plan has outlined the basis for the multidisciplinary team (MDT) management of rectal cancer. Advances in preoperative assessment through accurate staging and the recognition of the importance of the relationship of the tumour to the mesorectal fascia has allowed the selection of patients for a preoperative strategy to down-size/down-stage the tumour if this fascial layer is involved or threatened. Improvements in the quality of surgical resection through the acceptance of the principle of total mesorectal excision have ensured that optimal surgery remains the cornerstone to successful treatment. Further refinements of the MDT process strive to improve outcome. Accurate radiological staging, optimal surgery and detailed histopathological assessment together with consideration of a preoperative neoadjuvant strategy should now form the basis for current treatment and future research in rectal cancer.

Comparison of 5-fluorouracil/leucovorin and capecitabine in preoperative chemoradiotherapy for locally advanced rectal cancer

PURPOSE

To describe our experience with a bolus injection of 5-fluorouracil and leucovorin (FL) vs. capecitabine in terms of radiologic and pathologic findings in preoperative chemoradiotherapy (CRT) for locally advanced rectal cancer.

METHODS

The study enrolled 278 patients scheduled for preoperative CRT using two protocols with different chemotherapeutic regimens. Pelvic radiotherapy (50.4 Gy) was delivered concurrently with FL (n = 145) or capecitabine (n = 133). Surgery was performed 6 weeks after CRT completion. Tumor responses to CRT were measured using both radiologic and pathologic examination. Magnetic resonance volumetry was performed at the initial workup and just before surgery after completion of preoperative CRT. Post-CRT pathology tests were used to determine tumor stage and regression.

RESULTS

Radiologic examination showed that tumor volume decreased by 68.2% +/- 20.5% in the FL group and 68.3% +/- 22.3% in the capecitabine group (p = 0.970). Postoperative pathologic T stage determination showed that downstaging occurred in 44.3% of FL and 49.9% of capecitabine patients (p = 0.571). The tumor regression grades after CRT were Grade 1 (minimal response) in 22.6% and 21.0%, Grade 2 (moderate response) in 53.2% and 50.0%, Grade 3 (near-complete response) in 12.9% and 12.9%, and Grade 4 (complete response) in 11.3% and 16.1% of the FL and capecitabine groups, respectively (p = 0.758).

CONCLUSION

In the present study, the radiologic and pathologic findings did not reveal significant differences in short-term tumor responses between preoperative FL and capecitabine CRT for locally advanced rectal cancer. Long-term results and a prospective randomized trial are needed.

Preoperative loco-regional imaging in rectal cancer

Preoperative staging of rectal cancer can influence the choice of surgery and the use of neoadjuvant therapy. This review evaluates the use of endorectal ultrasound (ERUS) and magnetic resonance imaging (MRI) in the local staging of rectal cancer. Staging for distant metastases is beyond the scope of this review. A MEDLINE search for published work in English between 1984-2004 was carried out by entering the key words of ERUS, MRI and preoperative imaging and rectal cancer. Initially, 867 articles were retrieved. Abstracts were reviewed and papers selected according to the inclusion criteria of a minimum of 50 patients and papers published in English. Papers focusing on preoperative chemoradiotherapy and distal metastases were excluded. Thirty-one papers were included in the systematic review. The examination techniques and images obtained are discussed and the respective accuracy is reviewed. ERUS and MRI have complementary roles in the assessment of tumour depth. Ultrasound has an overall accuracy of 82% (T1, 2, 40-100%; T3, 4, 25-100%) and is particularly useful for early localized rectal cancers. MRI has an accuracy of 76% (T1, 2, 29-80%; T3, 4, 0-100%) and is useful in more advanced disease by providing clearer definition of the mesorectum and mesorectal fascia. Both methods have similar accuracy in the assessment of nodal metastases. Ultrasound is more operator dependent and accuracies improve with experience, but it is more portable and accessible than MRI. Improvements in technology and increased operator experience have led to more accurate preoperative staging. ERUS and MRI are complementary and are most accurate for early localized cancers and more advanced cancers, respectively.

An update on imaging of colorectal cancer

Screening of asymptomatic average-risk patients for presence of colon cancer and early detection in precursor stages is of great interest to general population. Comprehensive evaluation of symptomatic or high-risk patients represents another important clinical focus. Available techniques for total colon imaging, rectal cancer staging and the role of positron emission tomography are discussed.

The Role of Carcinoembryonic Antigen as a Predictor of the Need for Preoperative Computed Tomography in Colon Cancer Patients

A retrospective study of 117 patients with the diagnosis of colon cancer was performed to evaluate the clinical utility of the preoperative computed tomography (CT) scan and to assess the role of carcinoembryonic antigen (CEA) as a predictor of the need for CT scan in colon cancer patients. Forty-nine patients had a CT scan that altered their treatment. One hundred per cent of stage IV patients versus only 26.5 per cent of stage I, II, and III patients had their operative and/or treatment planning altered by the preoperative CT. The sensitivity of CT scan in predicting metastatic disease was 90.3 per cent. All patients with stage IV disease had an abnormal CEA (>3 ng/mL). There was 89.7 per cent of stage IV patients who had a CEA twice that of normal or above. By using a CEA level of 3.1 ng/mL or above as a prerequisite for preoperative tomography, 34 nonmetastatic patients would not have had preoperative CT scans. Using a prerequisite of 6.1 ng/mL or above, 49 nonmetastatic patients would not have had a preoperative CT scan, and 90 per cent of the stage IV patients would have been imaged. We recommend obtaining a preoperative CT scan on those patients with a CEA value twice that of normal or greater.

Preoperative evaluation of pelvic lateral lymph node of patients with lower rectal cancer: comparison study of MR imaging and CT in 53 patients

BACKGROUND

Preoperative assessment of the lateral pelvic lymph nodes is important for treatment strategy to patients with lower rectal cancer.

MATERIALS AND METHODS

Fifty-three patients with primary lower rectal cancer were preoperatively assessed by spiral computed tomography (CT) and magnetic resonance imaging (MRI) at 1.5 T with a phased-array coil. Preoperative tumor and lymph node stages were compared with the final histological findings.

RESULTS

The MRI tumor stage coincided with the histological stage in 36 of 53 patients (68%). The MRI and CT lymph node stage coincided with the histological stage in 33 (62%) and 26 (49%) of 53 patients, respectively. However the accuracy of MRI in detecting the lateral pelvic lymph node involvement was 83%, compared to 77% of CT (p<0.05).

CONCLUSIONS

With the use of MRI, the lateral pelvic lymph node involvement can be predicted with high accuracy, allowing preoperative identification of patients who need radiotherapy or extensive surgery to escape recurrence.

Efficacy of PET/CT in the accurate evaluation of primary colorectal carcinoma

AIM

This study was performed to assess in the accurate evaluation of primary colorectal carcinoma using PET/CT.

METHODS

One hundred patients with primary colorectal carcinoma were evaluated during 2004. All patients underwent PET/CT when their preoperative serum carcinoembryonic antigen was >or=10 ng/mL or when CT showed equivocal findings. The appropriateness of PET/CT-induced changes was noted by subsequent operative findings and follow-up.

RESULTS

PET/CT more detected 15 intra-abdominal metastatic lesions than abdomino-pelvic CT scan. PET/CT showed true negative findings in 13 patients and false positive or negative findings in 10. Due to PET/CT results, management plans were altered in 27 patients; 9 had inter-modality changes, 10 received more extensive surgery, and 8 avoided unnecessary procedures.

CONCLUSIONS

PET/CT altered management plan in 24% of patients with primary colorectal carcinoma in correct direction. These findings suggest that PET/CT should be considered a part of standard work up for preoperative evaluation in a subset of patients with colorectal carcinoma.

Endoscopic posterior mesorectal resection after transanal local excision of T1 carcinomas of the lower third of the rectum

PURPOSE

The rectum-sparing transanal local excision is a well-established treatment of T1 carcinomas of the lower third of the rectum. A potentially increased locoregional recurrence rate by this procedure is tolerated because of the high morbidity and mortality risk of transabdominal rectal resection. Dorsoposterior extraperitoneal pelviscopy makes it possible to remove the relevant lymphatic drainage of the lower third of the rectum minimally invasively, in the sense of a rectum-sparing endoscopic posterior mesorectal resection. It has to be considered whether endoscopic posterior mesorectal resection in combination with transanal local excision allows for local radicality and an adequate tumor staging in T1 carcinomas of the lower third of the rectum, in terms of better-directed therapy planning compared with transanal local excision alone.

METHODS

We operated on 11 consecutive patients with T1 carcinomas of the lower third of the rectum by transanal local excision in combination with endoscopic posterior mesorectal resection as a two-stage procedure in the period from 1998 to 2005.

RESULTS

It was possible to perform a complete excision of the primary and to resect the posterior part of the mesorectum in all cases. Postoperative morbidity consisted of two transient neurologic complications and a pulmonary embolism. There was no mortality. Histologic analysis revealed a median of eight (range, 4-20) lymph nodes. Two patients diagnosed with lymph-node metastases received adjuvant radiochemotherapy. After a median follow-up of 48 (range, 4-60) months, there was no evidence for locoregional recurrence. In one patient liver metastasis was detected eight months postoperatively.

CONCLUSIONS

Radical excision of the primary tumor and an adequate tumor staging in T1 carcinomas of the lower third of the rectum seems to be achievable by means of transanal local excision and endoscopic posterior mesorectal resection.

Is T classification still correlated with lymph node status after preoperative chemoradiotherapy for rectal cancer?

BACKGROUND

It is well known that the risk of lymph node involvement increases according to pathologic T classification in rectal cancers, but to the authors' knowledge, the correlation between risk of lymph node involvement and ypT classification in rectal cancers treated with preoperative chemoradiotherapy (CRT) remains unclear. The current study investigated the correlation between tumor involvement in regional lymph nodes and rectal mural tumor status in patients who underwent preoperative CRT for rectal cancer.

METHODS

Between October 2001 and February 2005, 282 patients underwent preoperative CRT followed by proctectomy for locally advanced rectal adenocarcinoma. Correlations between lymph node status and ypT classification, Dworak regression grade, and magnetic resonance (MR) volumetry findings were explored.

RESULTS

Lymph nodes harboring tumors were found in 87 of 282 (30.9%) patients. The rate of lymph node involvement was found to be correlated with ypT-classification (P < .001); positive lymph nodes were detected in 1 of 45 (2.2%) ypT0 patients, 1 of 13 (7.7%) ypT1 patients, 13 of 77 (16.9%) ypT2 patients, 69 of 140 (49.3%) ypT3 patients, and 3 of 7 (42.9%) ypT4 patients. The rate of lymph node involvement decreased as Dworak regression grade increased (P < .001); tumor-harboring lymph nodes were found in 62.3% of Grade 1 patients, 31.4% of Grade 2 patients, 16.1% of Grade 3 patients, and 2.2% of Grade 4 patients. There were no differences noted with regard to MR volumetry findings, including mean volume of pre- or post-CRT tumor and the tumor volume reduction rate between lymph node-negative and lymph node-positive patients.

CONCLUSIONS

Pathologic T classification is still the most reliable predictor of lymph node metastasis in rectal cancer patients who have undergone preoperative CRT. The risk of lymph node metastasis was found to be 3.4% in rectal cancer that had regressed to ypT0 or ypT1.

Bowel cancer: the outcome is improving

The management of rectal cancer has been revolutionised over the last 20 years through improvements in staging, surgery and the use of radiotherapy and combination chemoradiotherapy. The traditional approach involved surgery followed by pathological assessment of the specimen reporting the completeness of excision. Incomplete excision in many cases led to local recurrence of the cancer within the pelvis with the disabling symptoms of pelvic pain, bowel fistulation and bowel and bladder dysfunction. Indeed, many patients died with local recurrence alone and salvage therapy in these patients was rarely successful. However, the recognition of the advantage of pre-operative therapy for patients in whom surgery would not provide local cure has been a major advance. The ability to downstage/downsize the tumour before curative surgery has improved outcome. However, these pre-operative therapies are toxic and not without their own complications, therefore the select use, targeted at the appropriate patient, represents the 'gold-standard'. The development of magnetic resonance imaging staging that accurately predicts operability has completed this triad approach which is focused through the weekly multidisciplinary team meeting. National acceptance of these techniques and standards can only improve the outcome for patients with this disease.

Endosonographic imaging of anorectal diseases

OBJECTIVE

The normal sonographic anatomy of the anorectum, sonographic findings of anorectal diseases, and indications and limitations of endosonography compared with magnetic resonance imaging are reviewed. Methods. Endosonographic imaging was performed with a Siemens (Erlangen, Germany) FI 400 ultrasound scanner with an end-fire 7.5-MHz biplane endorectal probe and a B-K Medical (Sandhoften, Denmark) scanner with an 1850 axial-type side-fire 5.0- to 10.0-MHz rotating endoscopic probe.

RESULTS

Rectal carcinoma appears on endorectal sonography as a low-echogenicity lesion that abruptly interrupts the normal sequence of layers. The internal anal sphincter is seen very clearly on endoanal sonography, and it is easy to appreciate atrophy and small tears of this sphincter. Endoanal sonography cannot accurately show thinning of the external anal sphincter. Peroxide-enhanced endoanal sonography is especially useful for patients with recurrent perianal fistulas in whom scarring should be distinguished from recurrent fistulas and detection of the internal opening. However, sonography does not provide an adequate deep and global display of all adjacent pelvic and perineal spaces.

CONCLUSIONS

Endosonography can accurately stage primary rectal tumors and assess the internal anal sphincter. Peroxide-enhanced 3-dimensional imaging can increase the utility of endoanal sonography in detection and characterization of perianal fistulas and planning of optimal therapy. However, magnetic resonance imaging can be used a complementary modality to endosonography, especially for evaluation of external anal sphincter atrophy and deep pelvic inflammation.

The management of rectal cancer in a resource poor environment - a review

Rectal cancer is an increasing problem in the developing world. There is little written on how to manage this problem outside the confines of major teaching hospitals in Western Countries. In these centres debate surrounds preoperative staging, the use of preoperative radiotherapy and sophisticated sphincter preserving procedures. The literature is complex and of little relevance to those faced with a patient with rectal cancer in rural Africa or Asia far from the ivory towers. This review aims to combine the best of evidence based medical practice related to the management of rectal cancer with the practical realities of operating in resource poor environments. In this situation staging is by means of simple radiology and a clinical examination supplemented by an examination under anaesthetic. If there are no distant metastases and the tumour is freely mobile a resection can be attempted. An abdominoperineal resection is a good operation with a proven track record. If an anastomosis can be fashioned then an anterior resection is an excellent operation and should be performed extrafascially to avoid local recurrence. It is vital to counsel the patient preoperatively. The pros and cons of referral to a centre of excellence need to be discussed with the patient prior to any intervention.

p53 status and response to radiotherapy in rectal cancer: a prospective multilevel analysis

The aim of this study was to evaluate, in a prospective study, the predictive role of p53 status analysed at four different levels in identifying the response to preoperative radiotherapy in rectal adenocarcinoma. Before treatment, 70 patients were staged and endoscopic forceps biopsies from the tumour area were taken. p53 status was assessed by total cDNA sequencing, allelic loss analysis, immunohistochemistry, and p53 antibodies. Neoadjuvant treatment was based on preoperative radiotherapy or radiochemotherapy. Response to therapy was evaluated after surgery by both pathologic downstaging and histologic tumour regression grade. In all, 35 patients (50.0%) had p53 gene mutations; 44.4% of patients had an allelic loss; nuclear p53 overexpression was observed in 39 patients (55.7%); and p53 antibodies were detected in 11 patients (16.7%). In the multilevel analysis of p53 status, gene mutations correlated with both nuclear protein overexpression (P<0.0001) and loss of heterozygosity (P=0.013). In all, 29 patients (41.4%) were downstaged by pathologic analysis, and 19 patients (29.2%) were classified as tumour regression grade 1. Whatever the method of evaluation of treatment response, no correlation between p53 alterations and response to radiotherapy was observed. Our results do not support the use of p53 alterations alone as a predictive marker for response to radiotherapy in rectal carcinoma.

Estándares de calidad de la cirugía del cáncer de recto

The results of surgery for rectal cancer have classically been measured through indicators such as morbidity, mortality, and length of hospital stay. In the last few years other parameters have been included that evaluate healthcare quality such as the functional results of the surgical technique employed and quality of life. Total resection of the mesorectum, performed by experienced surgeons, is the surgical technique of choice. Currently, the sphincter can be preserved in 70% of patients. Anastomotic dehiscence after anterior resection of the rectum is the most serious complication and the most important risk factor is the height of the anastomosis. The overall dehiscence rate should be less than 15% and operative mortality should be between 2% and 3%. The colonic reservoir improves functional outcome and consequently it is the procedure of choice to reconstruct transit after low anterior resection. Local recurrence should be less than 10% and 5-year survival should be between 70% and 80%. In general, quality of life is better after anterior resection of the rectum than after abdominoperineal amputation, despite the functional deterioration presented by some patients.

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.

Usefulness of magnetic resonance volumetric evaluation in predicting response to preoperative concurrent chemoradiotherapy in patients with resectable rectal cancer

PURPOSE

We performed magnetic resonance (MR) volumetry before and after neoadjuvant chemoradiation for evaluating response to therapy in T3 and T4 rectal cancer. To investigate the utility of MR volumetry for predicting the response to neoadjuvant chemoradiation, we compared results from MR volumetry before chemoradiation with those after chemoradiation.

METHODS AND MATERIALS

A total 112 patients with T3 or T4 rectal cancer who successfully underwent MR volumetry and completed neoadjuvant chemoradiation followed by radical resection for cure were identified. MR volumetries were performed before and after chemoradiation. We compared pre- and postchemoradiation tumor volume and % volume reduction rates of patients whose tumors were down-staged with those of patients that were not down-staged. The same analyses were also performed between those patients having a complete histologic regression and those with residual disease in the operative specimen. We assessed the difference of % volume reduction rate according to Dworak's rectal cancer regression grades.

RESULTS

Fifty-seven patients (50.9%) demonstrated a tumor down-staging after chemoradiation therapy. Both pre- and posttreatment MR tumor volumes were significantly less in patients whose tumors were down-staged than in patients that were not down-staged (p = 0.04, 0.031), and % volume reduction rates were significantly higher in patients whose tumors were down-staged (p = 0.024). Sixteen patients (14.3%) showed pathologically complete tumor regression. The differences of MR tumor volumes before and after chemoradiation and % volume reduction rates were not significantly different between patients having a complete histologic regression and those with residual disease (p = 0.688, 0.451, and 0.480). The differences of % volume reduction rates according to Dworak's grades were statistically significant (p = 0.03).

CONCLUSION

The MR volumetric examinations before and after chemoradiation demonstrated the significant difference of tumor volume and % volume reduction rate between patients whose tumors were down-staged and those that were not down-staged. The volume reduction rates were significantly different among groups according to Dworak's grades. However, the MR volumetric evaluation could not identify any differences between those patients having a complete histologic regression and those with residual disease.