Role of endorectal ultrasound in the conservative management of rectal cancers.

Endorectal ultrasonography (ERUS) extends the ability of the clinician to define the clinical features assessed on routine physical examination, and remains the best modality for accurately staging depth of penetration and presumptive nodal status in rectal cancers. The success of conservative management of rectal cancers is predicated on proper patient selection. The preoperative selection of the ideal patient for local therapies can be difficult, and the decision-making process takes into account many critical factors. Careful assessment of the T and N stages is critical in determining the success of conservative therapies, and directing treatment algorithms. Local resections with curative intent are limited to patients with T1N0 rectal cancers, and select patients with T2N0 tumors with favorable pathological criteria. Conservative management may also be extended to patients identified with significant underlying comorbid conditions staged preoperatively with unfavorable T2/T3 lesions, often combined with adjuvant therapies in a palliative setting. In addition, ERUS may have a role in the selection of those patients with more advanced lesions to neoadjuvant chemoradiation, followed by radical resection. Though not clearly defined, ERUS is evolving in its role in the postoperative follow-up of patients treated conservatively for rectal cancers, and can lead to the early detection of local recurrences. The widespread use of ERUS remains limited due to high operator variability and errors in interpretation; however, the role of ERUS in the postoperative management of rectal cancers is evolving and requires further evaluation.