Trial Information

Prevalence of Stem Cell and Prognostic Markers in Circulating Tumor Cells of Patients With Metastatic Colorectal Cancer Undergoing Chemotherapy

Metastatic colorectal cancer (mCRC) has a five year survival of <10% and is the cause of
death of nearly 50,000 individuals in the United States each year. Current first and second
line therapies for mCRC include FOLFOX, XELOX, or FOLFIRI in combination with Bevacizumab or
Cetuximab or Panitumumab, as well as Xeloda, camptosar or infusional 5-FU within various
less intensive regimens for patients who cannot tolerate full-dose chemotherapy. Current
practice involves evaluation of response by imaging at 2-3 months after initiation of
therapy. Recent studies have demonstrated that the number of circulating tumor cells (CTCs)
in the blood of patients with mCRC has independent prognostic value in terms of reflecting
disease burden as well as indicating response to therapy. The use of CTC counts offers the
possibility of predicting response in treated patients at an earlier time than through
standard means by using CT scans. The investigators hypothesize that subsets of CTCs with
cancer stem cell (CSC) markers or other known prognostic markers may improve the prognostic
value of CTC evaluation in the course of therapy of patients with mCRC. The protocol will
use Veridex CellSearch technology and will when possible compare this to other emerging
technologies including microfluidic devices that can isolate CTCs or GFP-expressing
adenoviruses that replicate in telomerase-expressing epithelial tumor cells ex-vivo. The
protocol will enroll 200 patients with metastatic colorectal cancer receiving therapy.
Additional proposed laboratory studies may unravel important biological insights into the
relationship of CTC genomic and genetic profiles as they compare to the primary tumors.
Additionally the investigators hope to gain an understanding of potential subgroups of
patients that have very high numbers of CTCs or those with early relapse of CTC after early
reduction of CTC numbers. The impact of this research may be in better prediction of
response to mCRC therapy so that patients can be treated with second line or other
experimental therapy if they are unlikely to respond to their current therapy as predicted
by CTC evaluation.