New method for detecting colorectal cancer!

Japanese researchers from the National Cancer Center Hospital East, Kashiwa City have discovered a new way of detecting colorectal cancer. It involves putting naturally evacuated faeces through a filtration system to isolate colonocytes (colon cells) and then examining the cells by cytology (microscopy) and DNA (genetic) techniques. Their findings are reported in the December issue of Gastroenterology.

Researchers hypothesized that old colon cells would flake off into faeces as they were replaced by new cells. Normal cells would die quickly, but cancerous cells would survive a long time in faeces, meaning they could be detected.The researchers analysed faeces from 116 patients with colorectal cancer and 83 healthy volunteers. Faeces samples from all patients where put through a funnel-shaped filtration system. After filtration, they separated the normal cells from neoplastic (abnormal) cells using magnetic beads coated with mouse antibodies specific for a membrane antigen expressed on most normal and neoplastic human epithelial tissues.The researchers then analysed the retrieved cells using both cytological and DNA techniques. They found that:- Cytology alone showed atypical cells in 28% of colorectal cancer patients and none of the healthy volunteers;- DNA analysis showed genetic alterations in 71% of patients with colorectal cancer. It also showed alterations in 12% of the healthy individuals.- When analysis was limited to cases in which genetic alterations were present in cancer tissue, the detection rate for such alterations using these methods was 86%.Given these encouraging findings, researchers now intend to carry out a prospective randomized study to compare their new detection method with the standard hemoccult detection method to determine the actual specificity and sensitivity in a real screening population and to verify its clinical usefulness and medical economics.(Source: Gastroenterology 2005;129:1918-1927.)