Preoperative radiotherapy in rectal carcinoma. 2. The effect of irradiation on lymph node involvement

A total of 38 cases of advanced rectal cancer (non-radiation group; 25 cases, radiation group; 13 cases) was studied in order to clarify the effect of preoperative radiation therapy (42.6 Gy) on lymph node metastases in rectal carcinoma. In all cases, microcarbon was submucosally injected into the rectal wall the day before operation in order to increase the number of removable lymph nodes from resected specimens as many as possible. By this method, the number of lymph nodes detected per specimen increased from 40 to 60. The incidence of lymph node metastases was 38.5% in radiation group and 64.0% in non-radiation group. The mean number of lymph nodes with metastases was 8.6 in non-radiation group, however, 2.8 in radiation group. With regard to the relationship between size and number of positive lymph nodes, especially in small lymph nodes measuring less than 3 mm, the incidence of metastases was 6.4% in non-radiation group, whereas 0% in radiation group. As a result, it was evident that preoperative radiation therapy in rectal cancer would reduce the number of positive lymph nodes significantly and the effect of radiation was prominent in small lymph nodes.     

Assessing tumor perfusion and treatment response in rectal cancer with multisection CT: initial observations

PURPOSE: To use first-pass perfusion computed tomography (CT) to prospectively investigate tumor vascularity in rectal cancer and to determine whether any of the perfusion parameters would predict tumor response to chemotherapy and radiation therapy. MATERIALS AND METHODS: The institutional review board approved this study, and informed prior consent was obtained from participants. Perfusion CT of rectal cancer was performed with four-section multi-detector row CT in 15 patients (13 men, two women; mean age, 62.1 years; age range, 46-84 years). Five patients with prostate cancer served as controls. All patients with rectal cancer underwent 6-8 weeks of chemotherapy and radiation therapy followed by surgery. In nine patients, perfusion CT was repeated after completion of chemotherapy and radiation therapy. Contrast medium-enhanced dynamic CT was performed with a static table position for 45 seconds, and the data were analyzed by using commercial software to calculate tissue blood flow (BF), blood volume, mean transit time (MTT), and vascular permeability-surface area product. Perfusion parameters of normal rectum and tumor were compared. Perfusion parameters before and after chemotherapy and radiation therapy were compared. A tumor was considered to have responded if its stage at pathologic analysis indicated regression compared with the preoperative stage. Baseline perfusion values were compared between responders and nonresponders. Statistical analysis was performed with the Student t test. RESULTS: Rectal cancer showed higher BF and shorter MTT compared with those of normal rectum (P < or =.05). After chemotherapy and radiation therapy, tumors showed significant reduction in BF and increase in MTT (P < or =.05). There was a significant difference in baseline BF and MTT values between responders and nonresponders (P < or =.05). Tumors in three patients with high initial BF and short MTT showed poor response. CONCLUSION: Perfusion CT of rectal cancer can enable assessment of tumor vascularity and perfusion changes that result from chemotherapy and radiation therapy. In this small patient sample, tumors with initial high BF and short MTT values tended to respond poorly to chemotherapy and radiation therapy.     

Hepatic artery injection of I-131-labeled lipiodol. Part II. Preliminary results of therapeutic use in patients with hepatocellular carcinoma and liver metastases

Internal radiation therapy with transarterial injection of iodine-131-labeled iodized oil (Lipiodol Ultra-Fluide [LUF]) was evaluated in 15 patients with hepatocellular carcinoma and eight with hepatic metastases. Five patients with hepatocellular carcinoma received more than one injection. Treatment tolerance was excellent, as assessed clinically and by means of liver function tests. An analgesic effect was noted in the two patients with painful hepatocellular carcinomas. Serum alpha 1-fetoprotein levels dropped rapidly in 11 of the 12 patients with elevated basal values. An average reduction in tumor size of 50% was observed in the nine cases followed up with computed tomography. After 5-12 months of follow-up, six of the 15 patients with hepatocellular carcinoma were alive. Two of them had undergone liver transplantation. Histologic examination of one of the livers, removed 3 months after a third injection, revealed microscopic features highly suggestive of radiation effect in LUF-containing areas. In the group with widespread hepatic metastases, no objective response was noted, except for an analgesic effect in three cases.     

Assessment of radiotherapeutic effect on brain tumors by dynamic susceptibility contrast MR imaging: a preliminary report.

PURPOSE: The purpose of this study was to assess tumor vascularity of the brain by dynamic susceptibility contrast (DSC) MR imaging and to determine whether this method is clinically useful for monitoring radiation effects on brain tumors. We, furthermore, compared DSC MR imaging with single-photon emission computed tomography (SPECT) using technetium-99m diethylene-triamine-pentaacetic acid human serum albumin (99mTc-HSA-D) in the assessment of tumor vascularity in a limited numbers of cases. METHODS: Twelve patients with various kinds of brain tumors were studied. DSC MRI was performed on all patients before and after radiation therapy. SPECT using 99mTc-HSA-D was also performed in five patients. The rate of change in tumor blood volume in response to radiation therapy was evaluated with DSC MRI and SPECT. The rate of change in tumor volume in response to radiation was also measured. RESULTS: Ten patients were successfully studied. The rate of change in tumor blood volume correlated well between DSC MRI and SPECT. There was no significant correlation between the rates of change for tumor blood volume and tumor volume. Changes in tumor vascularity preceded the reduction in tumor volume seen following radiotherapy. CONCLUSION: DSC MRI provides information regarding radiation effects on tumor vessels that is not available with conventional MRI.     

Nonresectable adenocarcinoma of the rectum assessed by MR imaging before and after chemotherapy and irradiation.

Thirty-four patients with nonresectable adenocarcinoma of the rectum, defined as tumor fixation at digital examination, were examined with MR. All 34 patients had, according to MR imaging, perirectal tumor growth. In 23 (68%) of the patients, the tumor has reached an adjacent organ. Eight of these patients had disturbances of the MR characteristics in the adjacent organ which proved to be due to overgrowth, i.e., to tumor invasion into these structures. In the remaining 15 patients, without disturbed MR characteristics, 7 had tumor overgrowth at laparotomy. When there was a visible space between the tumor and adjacent organs, there was no sign of tumor overgrowth at laparotomy, except in one case. In 24 patients, examined both before and after combined irradiation and drug therapy, tumor regression was registered after treatment. MR imaging seems to be useful in the assessment of resectability and to evaluate preoperative anticancer treatment in patients with nonresectable rectal carcinoma.     

Preoperative staging of rectal carcinoma by transrectal echography combined with pelvic computerized tomography

The accurate staging of rectal carcinoma is very important for treatment planning. The histological data obtained from the surgical specimens of 22 patients with rectal carcinoma were compared with pre- and postoperative endorectal US findings and with preoperative CT results. According to an adapted version of the Astler and Coller classification, the different degrees of tumor spread into the rectal wall were represented as follows: stage A: 1 patient; stage B1: 5 patients; stage B2: 6 patients; stage C1: 1 patient; stage C2: 8 patients and stage D: 1 patient. Preoperative staging, based on the overall results of CT and US, was in agreement with histology in 19 of 22 cases. Individual analysis of US and CT results, in comparison with histological data, showed US staging accuracy to be 77.3% (17/22 patients). US accuracy in demonstrating tumor spread into the rectal wall (stages A, B1, C1) was 100% (7/7 patients); US was 70% accurate in lymph node detection (7/10 patients) and 93.3% accurate in demonstrating perirectal infiltration (14/15 patients). CT diagnostic accuracy was 66.7% (10/15 patients) in the evaluation of perirectal lymph nodes, but tumor spread into the rectal wall (stages A and B1) could not be evaluated. While admitting the primary role of US in the staging of rectal carcinoma, according to our results a combination of US and CT yields a more accurate preoperative diagnostic picture.     

Rectal cancer: review with emphasis on MR imaging

One concern after rectal cancer surgery is the high local recurrence rate. Randomized trials have shown that the best local control rate for rectal cancer patients as a group is achieved after a short course of radiation therapy followed by optimal surgery. It is debatable, however, whether all patients with rectal cancer should undergo preoperative radiation therapy. Preoperative identification of those most likely to benefit from neoadjuvant therapy is important. Therefore, the challenge for preoperative imaging in rectal cancer is to determine subgroups of patients with different risks for recurrence: those with superficial tumors, who can be treated with surgery alone; those with operable tumors and a wide circumferential resection margin, who can be treated with a short course of radiation therapy followed by total mesorectal excision; and those with advanced cancer and a close or involved resection margin, who require a long course of radiation therapy, with or without chemotherapy, and extensive surgery. So far, there is no consensus on the role of diagnostic imaging (endorectal ultrasonography, computed tomography, and magnetic resonance [MR] imaging) in the care of patients with primary rectal cancer. Preoperative staging has long relied on digital examination alone, which indicates that it has been difficult to achieve accuracy levels high enough for clinical decision making with preoperative imaging. In this review, the relevance of preoperative imaging in staging the local extent of primary rectal cancer will be discussed. Research on various imaging modalities, with an emphasis on MR, will be discussed under four main headings that address the most relevant aspects of local spread of rectal tumors: T stage, circumferential resection margin, locally advanced rectal cancer, and N stage.     

Rectal carcinoma treated by preoperative irradiation: MR imaging and histopathologic correlation.

We evaluated the role of MR imaging in assessing the effect of preoperative irradiation in 11 patients with primary rectal carcinoma. Findings on MR images obtained before radiotherapy and 5-6 weeks afterward were analyzed and correlated with the histopathological findings (nine patients) or the findings at laparotomy (two patients). Before irradiation, the tumor volumes on MR images were between 3.3 and 51.7 cm3 (mean 19.7 cm3). After irradiation, the volumes were from 0.8 to 33.2 cm3 (mean, 10.4 cm3), representing a decrease in volume of 11% to 88% (mean, 55%). On the MR images obtained before irradiation, the tumors were confined to the bowel wall in four cases (stage A-B1), penetrated the perirectal fat in six cases (stage B2), and involved an adjacent organ in one case (stage B3). After irradiation, no apparent changes were seen in the MR appearance of the local tumor stage in nine of the 11 patients. In one patient, progression of stage was suspected on the postirradiation MR images, but this was not confirmed at histologic examination. In one patient, possible downstaging occurred after irradiation, although this could not be proved. Our findings suggest that MR imaging may be useful for determining the effect of preoperative radiotherapy on rectal carcinomas.     

64层螺旋CT灌注成像评价直肠癌术后复发或瘢痕组织

目的:应用64层螺旋CT灌注成像研究直肠癌术后复发或瘢痕组织的血流灌注情况,判断各种灌注成像参数与直肠癌术后复发或瘢痕组织是否存在相关性。方法:20例T3、T4期直肠癌患者,手术前及手术后6个月行2次多层CT灌注成像,所有病例手术前均经肠镜证实。采用64层CT扫描机,动态电影模式扫描,所有数据经工作站软件处理,计算组织血流量(BF),血容量(BV),平均通过时间(MTT)和血管表面通透性(PS)。比较直肠正常部位与肿瘤组织、术前肿瘤组织与手术后软组织肿块各灌注参数的变化。结果:直肠癌组织BF值明显升高、MTT值明显降低,与正常直肠组织相比差异具有显著性意义(P<0.05)。术后复发肿瘤组织BF值明显升高、MTT值明显降低;术后瘢痕组织BF值明显降低、MTT值明显升高;复发组织与瘢痕组织BF、MTT值差异有显著性意义(P<0.05)。结论:64层螺旋CT灌注成像能有效评价直肠癌患者术后复发或瘢痕组织血管灌注情况的变化,对判断直肠癌术后复发具有重要价值。     

DNA measurements and micronuclei in human rectal carcinoma

It has been recognized that the variability among individual human tumors is tremendous. We investigated DNA content and cell proliferation in 81 patients with rectal carcinoma by cytophotometric methods. Among them, 32 patients showed only diploid cells and 41 patients hyperploid cells, and the former had better prognoses than the latter. The percentage of S cells calculated from the DNA histograms and the number of cells with micronuclei were higher in proliferative tumors. Clinically, probably due to repopulation in the tumor 10 to 15 days after preoperative radiotherapy, the number of S cells increased and local recurrence was found several months after surgical resection in more than a few cases. These data suggest that the biological variability of human tumors is extraordinary and individualization of tumor therapy is greatly indicated. Furthermore, the above parameters may help to obtain indicators for the prognosis and thereby improve therapy.     

Restaging of Locally Advanced Carcinoma of the Rectum with MR Imaging after Preoperative Radio-Chemotherapy plus Regional Hyperthermia

BACKGROUND: The restaging accuracy of MR imaging in advanced primary rectal carcinoma after preoperative radiochemotherapy and regional hyperthermia was evaluated and compared with the histopathologically verified degree of tumor remission after a course of radio-chemo-thermotherapy. PATIENTS AND METHODS: 35 patients with primary rectal carcinoma (uT3/uT4) underwent MRI using a surface coil 4-6 weeks after radiochemotherapy (n = 35), regional hyperthermia (n = 23), and before curative surgery. We defined as gold standard for the remission status the comparison of pretherapeutic endosonography with the histopathology of the resected specimen. RESULTS: T category was correctly restaged after preoperative treatment in only 19 (54%) of 35 patients. Nine of 20 responders were overstaged and seven of 15 non-responders were understaged. Concurrently, the N category was correctly restaged in 19 (54%) of 35 patients (twelve responders and seven non-responders). Overstaging occurred in four responders and two non-responders, understaging occurred in four responders and six non-responders. CONCLUSIONS: MRI proved independent of the response status as not suitable to restage locally advanced rectal carcinoma after preoperative radiochemotherapy despite optimized imaging technique and spatial resolution. Basically, imaging the morphology of a tumor cannot clearly differentiate between vital and devitalized tissue after a treatment. Functional imaging such as PET (positron emission tomography) appears more feasible for restaging after radio-chemo-thermotherapy.     

螺旋CT在直肠癌诊断及其术前分期中的价值

目的：探讨直肠癌的CT表现及其术前分期价值。方法：对33例经内镜或手术活检病理证实为直肠癌的患者进行CT回顾性阅片，分析其CT征象并进行术前分期．并将CT表现与病理结果进行对照。结果：直肠癌CT表现为肠壁增厚、肠腔狭窄、软组织肿块及周围组织结构侵犯、区域淋巴结肿大和远处转移。直肠癌术前CT分期诊断和病理分期的总符合率为92％。结论：直肠癌的CT征象具有一定的特征性，CT在直肠癌术前分期中具有较高的准确性，对治疗方案的确定具有重要参考价值。     

Clinical assessment of tumor clearance during radiotherapy as a prognostic factor of early glottic carcinoma.

From 1967 through 1985, 358 cases of early glottic carcinoma were treated with telecobalt therapy at the Department of Radiology, Osaka University Medical School. Among 278 cases treated with 2 Gy a day, the tumor response of 262 cases at 40, 50 and 60 Gy were evaluated by direct or indirect laryngoscope. The five-year local control rates of these evaluable cases of T1 and T2 glottic carcinoma were 79% and 70%, respectively. The local control rates of T1 glottic carcinoma with tumor clearance and persistence at 40 Gy were 83% (119/143) and 64% (43/67), and those of T2 cases were 86% (18/21) and 58% (18/31), respectively. The local control rates of the cases with tumor clearance and persistence at 40 Gy were same between T1 and T2 cases. The tumor clearance rates of T1 cases were significantly higher than those of T2 cases (p < 0.005). T2 glottic carcinoma had larger tumor volumes and slower tumor regression and resulted in lower control rates compared with T1 glottic carcinoma. The difference in the radiation dose of T1 and T2 glottic carcinoma with the same clearance rate was estimated as 15 Gy using logit analysis.     

Bedeutung der Wartezeit bei Tumorpatienten am Beispiel der Vorbehandlung des lokal fortgeschrittenen Rektumkarzinoms

BACKGROUND: With the intention to achieve tumor reduction and thereby increase R0-resection rate, preoperative radiochemotherapy is increasingly applied in locally advanced rectum cancer. Along with the advantages of prior therapy, a delay of surgical treatment occurs which might despite continuing therapy give way to local tumor progression or metastatic disease. PATIENTS AND METHODS: Since 1993 we have treated locally advanced rectum carcinomas by preoperative radiotherapy according to a preoperative study protocol. We analyzed the incidence of local tumor progression or metastases during the 12 weeks of preoperative treatment. Hundred and fifteen patients with histologically proven primary rectum carcinoma without evidence of regional or distant metastases and endosonographically determined infiltration depth of stage T3 or more underwent preoperative radiochemotherapy between 3/1993 and 10/1999. Hundred and eight patients (88 times uT3 and (20 times uT4) have been operated and examined afterwards with respect to response to prior treatment. Before and after preoperative therapy, endorectal ultrasound was performed to evaluate local response. Distant metastatic manifestations were excluded by radiography and ultrasound scanning. RESULTS: A reduction of the infiltration depth was observed in 55 patients (51%). Tumor size remained unchanged in 50 patients (46%). Only 3 patients (3%) showed tumor growth in histological assessment. Fifty-seven patients (53%) showed no change in lymph node status after preoperative therapy, whereas lymph node metastases were detected in 11 patients (10%) who were judged uN0 preoperatively. We discovered metastases in 6 patients (6%) after preoperative therapy. CONCLUSION: During preoperative therapy, tumor progress is not entirely evitable. Considering the lack of precision in pretherapeutic staging diagnostics, we conclude that delays due to therapeutic regimen are responsible for prognostic disadvantage in only a small number of patients.     

Rectal carcinoma: CT staging with water as contrast medium

Computed tomography (CT) was used to study 42 patients with rectal carcinoma. Water was used as a contrast medium for studying the local extent of tumor in all patients. Scans were read prospectively without knowledge of the histologic staging and then compared with pathologic specimens. CT depicted the tumor in all patients. Comparison of CT and histologic results (following the Dukes classification) showed that disease was correctly staged as A in three of four patients, as B in eight of 12, as C in 15 of 17, and as D in nine of nine. Overall, carcinoma was correctly staged with CT in 35 of 42 patients (diagnostic accuracy, 83.3%). The accuracy in the assessment of local invasion was 97.6% (41 of 42). In the detection of lymph node involvement, the accuracy was 78.6% (sensitivity, 88%; specificity, 64.7%). CT is recommended in the preoperative staging of rectal carcinoma and as an aid in choosing the appropriate therapy. The use of water enema and complete distention of the rectum are reliable techniques for improving the accuracy of CT in the assessment of local invasion by cancer.     

Computed Tomogram prior to Prostatectomy Advantage in Defining Planning Target Volumes for Postoperative Adjuvant Radiotherapy in Patients with Stage C Prostate Cancer?

PURPOSE: To evaluate the influence of a preoperative computed tomogram (CT) on delineation of the planning target volume (PTV) for adjuvant radiation therapy of pT3 pN0 prostate cancer. PATIENTS AND METHODS: PTVs of ten patients who had an additional preoperative CT examination were contoured by three independent radiation oncologists. PTV included the former prostatic bed and seminal vesicles with a safety margin. First PTVs were drawn without knowledge of the preoperative CTs and in a second attempt, this procedure was repeated with these CTs available for visual comparison. Changes in PTV dimensions for every patient were analyzed. RESULTS: In 93% of all PTVs there was a decision to increase the PTV after viewing the preoperative CT images. Mean PTV length increased from 7.3 to 8.4 cm and PTV volumes expanded 26% from 244 to 308 cm3. These differences were statistically significant for all three participating radiation oncologists. CONCLUSION: Planning target volume definition probably is a critical factor in adjuvant radiation therapy after radical prostatectomy. As there is a considerable incertainty in PTV definition a preoperative CT is helpful and therefore may have beneficial influence on results.     

Phase-II-Studie zur präoperativen Radio-Chemo-Thermo-Therapie beim lokal fortgeschrittenen Rektum-Karzinom

Background

Recent studies show that preoperative radio-chemotherapy can increase resectability and local control of locally advanced rectal carcinomas. Additional regional hyperthermia might increase remission rates and tumor response. We therefore tested regional hyperthermia together with radio-chemotherapy in a phase-II study on locally advanced rectal carcinomas.

Patients and Methods

Thirty-seven patients with primary advanced stage uT3/T4 rectal carcinomas were treated with preoperative radio-chemo-thermo-therapy. The initial tumor depth was determined using endosonography, CT, and MRI. Radiotherapy was carried out in prone position (on a belly board) using standard techniques, with 5 × 1.8 Gy per week up to 45 Gy at the reference point. 5-Fluorouracil (300 to 500 mg/m²) was administered with low doses of leucovorin (50 mg) on days 1 to 5 and 22 to 28. The patients were treated with regional hyperthermia each week prior to radiotherapy and simultaneously with chemotherapy, using the Sigma 60 ring from the BSD-2000 system. Temperature/position curves and temperature/time curves were recorded in endocavitary (endorectal) catheters in tumor contact and as well in bladder and vagina. Following endosonographic restaging, the operation was carried out 4 to 6 weeks after the end of preoperative therapy and adjuvant chemotherapy continued in four cycles. In cases where tumors were non-resectable, a boost up to 64 Gy was aimed.

Results

Thirty-one of the 37 patients (84%) with primary carcinoma proved locally R0-resectable. In addition we had 1 R1-resection (3%) and 5 non-resectable tumors (13%). Among the resected tumors, 53% experienced a reduction of depth infiltration from the initial endosonographic stage during preoperative therapy. The actuarial, survival rate after 4 years is 65% (free of progression 57%). The actuarial 4-year survival rate was particularly favorable for the group of responders. Overall, the preoperative multimodal therapy was well tolerated, and premature termination was only necessary in 1 case (3%). Grade III/IV toxicities in the intestine and skin were reduced as far as possible by field blockings and cooling of the perineal region. They occurred only in 5/37 patients (13%) at the intestine and in 6/37 patients (16%) at the skin. The thermal data were subjected to a statistical analysis. The quality of temperature distribution (T₉₀, cum min T₉₀≥40.5 °C) depends on the power level and relative power density. The response (reduction of tumor size or depth infiltration) correlated significantly with quality parameters of the temperature distributions. This dependency is found as a trend for progression-free survival, too.

Conclusions

Preoperative radio-chemo-thermo-therapy proved to be practical and effective, with encouraging remission rates and excellent local control rates. For this reason, a phase-III study to test regional hyperthermia has been initiated. At the same time, certain technical improvements are still under development for regional hyperthermia.     

Computed tomography of the urinary bladder shortly after radiation therapy for rectal carcinoma

Eighteen patients with rectal carcinoma were examined with computed tomography (CT), before and shortly after preoperative irradiation. Changes in the bladder that could be mistaken for tumor growth did not occur at CT. However, considerable individual variations were seen. Radiation therapy did not result in increased contrast enhancement of the bladder wall after irradiation. The bladder wall thickness increased somewhat during and after treatment and the bladder volume was reduced. Localized thickening with little contrast enhancement was seen in the anterior bladder wall in 3 patients. One case of irradiation cystitis was noted. Edema was seen in the perivesical fat, but could in no case be mistaken for tumor growth.     

Carcinomatous neuropathy in recurrent rectal carcinoma. The results of radiotherapy and the role of CT

More than 60% of the patients with recurrent rectal carcinoma complain of pain after radical surgery. Pelvic carcinomatous neuropathy (PCN) is a frequent cause of pain in such patients. Although the effectiveness of radiotherapy in the palliative treatment of local recurrences of rectal carcinoma is well recognized, its results in PCN are less known. The authors have evaluated the results of high-energy radiotherapy in 12 patients with recurrent rectal carcinoma and PCN, who were treated with doses between 35 and 55 Gy. Although the survival of these patients is always poor, about 50% of them achieved a significant and prolonged palliative result by radiation treatment. In patients with PCN, CT is an effective tool to detect recurrences, define their volume and relationship to critical organs, show sites of neural involvement, and optimize radiation treatment planning.     

MR-endoscopic US correlation for loco-regional staging of rectal carcinoma

INTRODUCTION: To correlate findings at high-resolution MR and endoscopic US (EUS) for preoperative loco-regional staging of rectal carcinoma. PATIENTS AND METHODS: Fifty-two patients with rectal carcinoma underwent high-resolution MR imaging. Only 43 of these patients underwent EUS due to technical limitations and stenosing carcinomas. Morphological imaging features and TNM staging were evaluated for both imaging modalities. The degree of correlation and accuracy were calculated for both. RESULTS: The correlation between MR and EUS was good for tumor length and thickness (r=0.7 and 0.61) for for nodal (N) staging (k=0.53). Correlation was good for T1 and T2 stages (k=0.51) and T3 stage (k=0.43) and very poor for stage 4 (k= -0.09), because no T4 lesion was detected at EUS. 81.8% of patients where T stage was over-estimated on MRI and 100% of patients where T stage was over-estimated on EUS had received preoperative radiation therapy. Therefore, results should be interpreted with caution. The predictive evaluation of tumor resectability (absence of perirectal fascia invasion) with a circumferential margin on MR> or =5 mm was 93%. CONCLUSION: Correlation between MR and EUS was moderate for T staging, because of limitations of EUS for large tumors. Results confirm that high-resolution MRI is useful for loco-regional staging of rectal carcinoma, especially for large tumors. EUS should be limited to the valuation of superficial tumors of the rectum.