Current staging paradigms have significant limitations. Histopathology
has been the gold standard for staging patients with colorectal
cancer. Although the clinical limitations of histopathology have
been well established scientifically, a viable alternative has not
been available. These limitations include:
Clinical Limitations of Histopathology
Sampling Error
<1.0% of available
tissue is reviewed
Sensitivity
Reliable lower limit of
detection of 1 cancer cell in 200 normal cells
Since staging is the single most important prognostic indicator
and determines treatment decisions, the accuracy of the assay used
to establish stage can significantly influence patient management
and their disease-free and overall survival. This is particularly
relevant for patients classified as lymph node-negative, who typically
are denied chemotherapy, since their lymph nodes may harbor occult
micrometastases that escape detection by standard methodologies.
Indeed, these occult micrometastases likely underlie the high (30%)
recurrence rates in patients who are lymph node negative.