DIAGNOSTIC YIELD OF PREOPER, ATIVE ENDORECTAL ULTRASONOGRAPHY FOR LOWER RECTAL CANCER STAGING
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0 bjectives: This study was designed to evaluate the diagnostic accuracy of endorectal ultrasonography (ERUS) as a modality for preoperative staging of cancer rectum and its applicability as screening test for cases with early cancerous lesias. Patients & Methods: The study comprised 40 patients; 29 males (72.%) and II females (27.5%) patients with mean age of 52.6±5.2 years and had rectal cancer diagnosed using colonoscopic biopsy and assigned for curative resection of the tumor. All the cases underwent preoperative pelvi-abdominal ultrasonographic and CT examination. Then all patients underwent preoperative ERUS. Results: Thirty patients (75%) underwent low anterior resection, while the other 10 (25%) underwent abdominoperineal resection (APR). No patient received preoperative radiotherapy or chemotherapy. The tumor mass and mesorectum enveloped within the visceral endopelvie fascia were removed as an intact unit and sent for histopathological examination. Hileen patients had anteriorly situated, 11 patients had laterally situated, 9 patients had posteriorly siiiiiited tunior and 5 patients had circumferential tumor. Mean distance of tumor from dentate line was 4.8 I 0.9: range- -- - -5-6.5 cm; 27 tumors were on distance <5 cm; while the other 13 tumors were placed on distance-s. Seven lesions were ulcerative, 15 ulcerofungating, 12 ulceroinfiltrative lesions and 6 were polypoid lesions. Mean tumor maximal diameter was 3.7±0.8; range: 2-7 cm. Ten lesions were well, 22 lesions were moderately and 8 lesions were poorly differentiated. As regards depth of tumor invasion (T stage), in comparison to postoperative histopathological examination of excised specimen, ERUS correctly predicted the T stage in 32 patients (80%), over-staged tumors in 5 patients (12.5%) and under-staged tumors in 3 patients (7.5%). ERUS detected 28 nodal free lesions and 12 lesions had nodal extension. ERUS examination properly depicted tissue invasion with sensitivity rate of 91.4% and accuracy rate of 80% and using ROC curve analysis, ERUS could be used as screening test for detecting early lesions with AAC= 0.905. ERUS examination was found to diagnose superficial tumors (T1 stage) with higher specificity (AUC=0.679) than more invasive lesions AUC=0.591, 0.607 and 0.636, for T2, T3 and 74 lesions, respectively. ERUS could detect nodal involvement with an accuracy rate of 83.3% Conclusion: ERUS is an appropriate diagnostic modality for staging of cases of cancer rectum with sensitivity rate of 91.4% and accuracy rate of 80% and could be used as screening test for detection of superficial (stage T1) lesions with high specificity thus aiding early surgical management with conservative surgeries and spare the net(' for preoperative multimodality debulking therapies.