The use of colonoscopic ultrasound in the management of patients with malignant colorectal polyps

The aim of this study was to assess the use of colonoscopic ultrasound in the evaluation of residual disease and local lymph nodes after polypectomy (removal of polyps). The results show that high-frequency ultrasound is beneficial for the assessment of colorectal malignant (cancerous) polyps (abnormal tissue growth).

Patients who received polypectomy for malignant polyps are a management challenge. Surgery or endoscopic surveillance is decided by balancing the surgical risks and the risk of local lymph node metastasis (spread of cancer). However, studies have shown that the increased risk of lymph-node metastasis is related to the depth of invasion into the colon wall. One of the new methods for risk assessment is endorectal (inside the terminal part of the large bowel) ultrasound.

This study was conducted between 2008 and 2010 on 21 patients who were identified with localised cancer after endoscopic polypectomy. Endoscopic ultrasound was performed 3 months after the polypectomy. Also, all the patients received a CT scan to detect the presence of local lymph nodes and distant metastases. Patients were followed up with clinical visits every 6 months, a CT scan at 24 months and a colonoscopy at 3 years.
The results of the study showed that the rectum was the most frequent location of the polyps. Also, more than 70 % of the polyps were sessile (or attached by a broad base). The colonoscopic high-frequency ultrasound did not detect residual disease or spread to local lymph nodes at the polypectomy site in any of the patients. Abnormal findings were present in 38% of the patients, but the histological analysis proved it was only scar tissue.
 

In conclusion, this study indicates that most patients with apparently malignant colorectal polyps can be managed after endoscopic polypectomy without the need for major surgery. Even if definitive management cannot rely only on ultrasound results, this method may prove to be a useful predictor of a poor outcome.