Counting of tumour cells in the bloodstream could help
monitor treatment progress in patients with castration-resistant prostate
cancer, new results show.
At a conference in Lugano, Switzerland,
organized by the European Society for Medical Oncology, researchers showed that
changes in the number of circulating tumor cells predicted the outcome after
chemotherapy in this hard to treat cancer.
"The results add to a growing body of evidence showing
that counting these cells is a valuable method for predicting survival and for
monitoring treatment benefit in these patients", said Dr. David Olmos from
The Royal Marsden NHS Foundation Trust in the UK.
"Our study shows that circulating tumor cell counts
could provide information about how patients are responding to therapy earlier
than other markers such as prostate-specific antigen (PSA) or time-to-disease
progression," he said. "We have observed that patients with declining
numbers of circulating tumor cells can see a change in their initial prognosis,
reflecting a potential benefit from therapy."
Among the 119 patients in the study, researchers found that
those with the lowest circulating cell counts had on average the longest
"Cancer cells can be detected in the circulating blood
by a range of methods", Dr. Olmos said. "The technique we used in our
study is classified as a cytometric approach. We use an antibody that is widely
expressed by epithelial cancer cells, and then use a range of cell-staining
techniques to ensure it is a cancer cell."
"Because these circulating cells have broken away from
either primary tumors or metastatic sites in other parts of the body, they
could potentially be used to help study the specific characteristics of the
cancer and perhaps personalize therapy", Dr. Olmos said.