Predictive ultrasound factors of lymphatic invasion in rectal cancer: "extra-corporeal" study.

OBJECTIVE: the accuracy of preoperative endorectal ultrasound in the status evaluation of lymph nodes is around 50-70%, with a lack of eco-morphological patterns of clinical use. Since, accurate local staging is of great value in prognosis and decision-making we decided to analyze the referenced eco-morphological parameters in a try to find a proper predictive tool of clinical help that could improve the accuracy of rectal ultrasound. MATERIAL AND METHOD: the resected specimens of 24 patients that were operated on by radical surgery because rectal cancer, without preoperative radiotherapy were suspended in warm water and ultrasound scanned (360º circular probe with a transducer of 10 Mhz). All suspicious nodes were recorded and marked for the definitive histological report. RESULTS: from the 24 specimens, 318 nodes were imaged(210 benign and 100 involved). All ultrasound parameters analysed were significant but only lobulation, echogenicity and hilar reflection were independent values. An score system was design with the addition of all parameters that showed a sensitivity of 98%and specificity of 99,1%. CONCLUSIONS: our study shows that a careful study of ultra-sound lymph node images can get a high level of accuracy and better help in tailoring the treatment of any particular case.

Anal endosonography for the study of anal canal anatomy: normal images and sonographic variants.

OBJECTIVE: To present normal images and sonographic variants of the anal canal to be used as reference for the study of sphincter and anal canal abnormalities. MATERIAL AND METHODS: Sixty subjects without known anal canal disease were studied by means of anal endosonography. Subject were divided according to age in two groups (up to 50 years and more than 50 years). All of them underwent an outpatient study with B&K medical ultrasound 2,003 scanner and 1,850 multifrequency transducer. RESULTS: Four layers can be sonographically identified in the anal canal: an inner hyperechoic layer which is the submucosa, a second hypoechoic layer which is the internal sphincter, a third one which is a longitudinal muscle and the outer hyperechoic layer which is the external sphincter and the only to be found in the low anal canal. In people older than 50 years, both sphincters were significantly thicker (0.3-0.5 mm). At the high anal canal 40% of women presented an anterior gap in the external anal sphincter. CONCLUSIONS: Anal endosonography allows an easy division in high-, mid-, and low anal canal. In some women there is a gap at the mid-high anal canal that must be taken into account in order to avoid diagnostic errors. An internal sphincter thickness greater than 3.5 mm should be considered abnormal at any sex or age.

Transanal endoscopic surgery for rectal tumors.

OBJECTIVE: To report our results with local excision by transanal endoscopic microsurgery (TEM) to treat 42 cases of rectal lesions (29 adenomas and 13 carcinomas). METHODS: Prospective, descriptive study. Sex distribution: 55% men, 45% women, mean age 65 years (range: 17-84 years). SYMPTOMS: rectal bleeding 67%, diarrhea 23%. SURGICAL TECHNIQUE: mucosectomy 6 cases, full-thickness excision 36 cases. Average follow-up: 11 months (range: 1-36 months). RESULTS: We analyzed operating time (average 85 min; range: 25-180 min), bleeding (average 100 ml, range 10-350 ml), distance of the tumor from the anal verge (lower tumor margin: mean, 8.8 cm; range, 1-20 cm; distal tumor margin: mean, 12.9 cm; range, 5-22 cm), tumor size (mean, 3.9 cm; range, 2-10 cm), postoperative hospital stay (average, 4 days; range, 2-15 days), morbidity (hemorrhage 1 case; perforation, 1 case), mortality (0) and follow-up (temporary incontinence to flatus in 6 cases, 1 recurrence of carcinoma treated with abdominoperineal resection, 2 recurrences of adenoma and 2 new adenomas). CONCLUSIONS: TEM is a safe technique for the treatment of rectal lesions. Low morbidity and recurrence rates and short hospital stays make TEM a procedure of choice when local rectal surgery is indicated.

Endoluminal ultrasography for rectal tumors: efficacy, sources of error and limitations.

OBJECTIVES: endorectal ultrasound (EUS) is currently accepted as the best technique for the preoperative study of patients with rectal tumors, and surgical decisions depend increasingly on EUS staging. The main pitfalls in staging rectal tumors are over- or understaging as well as errors in imaging lymph nodes. Being aware of such errors and their causes may help to improve the overall results. The aim of the present study was to evaluate the accuracy of EUS in staging rectal neoplasms, and to study potential sources of error. METHODS: from May 1996 to December 1998, 120 patients with rectal tumors were studied preoperatively by EUS. The uTNM classification described by Hildebrandt and coworkers was used. The EUS findings were compared prospectively with the results of pathological examination. When there was no correlation, both the specimen and the EUS findings were carefully reviewed to look for potential sources of error. RESULTS: 41 out of 120 patients were classified as uT1, 10 as uT2, 60 as uT3 and 9 out of 120 as uT4. 31 patients had positive lymph nodes (uN1). On comparing these data with the results of the pathological report, we found 90% accuracy in staging rectal wall penetration, and 70% accuracy in the diagnosis of lymph nodes. Errors were due basically to technical problems, characteristics of the tumor itself, and difficulties in staging lymph nodes. CONCLUSIONS: it is important to identify the potential source of errors as well as the current limitations of EUS to improve the overall results with this technique.