ENDOLUMINAL ULTRASOUND AND LOW-FIELD MAGNETIC-RESONANCE-IMAGING ARE SUPERIOR TO CLINICAL EXAMINATION IN THE PREOPERATIVE STAGING OF RECTAL-CANCER

Objective. To compare digital examination, endoluminal ultrasound (ELU ), and plain magnetic resonance imaging (MRI), with histopathological findings in the preoperative staging of rectal cancer. Design: A prosp ective comparative study. Setting: University hospital, Sweden. Subjec ts: 35 patients with rectal cancer who presented during the period Feb ruary 1987 to February 1991. Results: The digital examination of 19 pa tients could be assessed and was correct in 13 (68%). ELU was done in 34 patients; the accuracy was 88 %. Extension of tumour was overestima ted in two and underestimated in two. MRI was done for 35 patients wit h an accuracy of 66%, in 12 patients extension was underestimated. The diagnostic accuracy of the assessment of lymph node involvement was 7 1% with ELU, and 72% with MRI. Conclusion: These findings indicate tha t MRI seems to underestimate the extension of rectal tumours, but both ELU and MRI can be helpful in selecting patients with advanced tumour s for whom preoperative adjuvant treatment is being considered. ELU is superior in staging tumours confined to the rectal wall, and could be of value in the selection of patients whose tumours were suitable for local excision. None of these techniques, however, can reliably ident ify the extent of lymph node involvement.