Circulating Tumor Cells and Early Diagnosis

A recent report describing a novel application of the cell search technology developed by Veridex, LLC (a subsidiary of Johnson & Johnson) may provide an extremely sensitive tool for the early detection of cancer. Four major cancer centers in the United States will conduct an analysis to determine the accuracy of this method for early diagnosis.

Over recent years, it has been recognized that cancer patients circulate small numbers of tumor cells in their blood. Using microbead technology, these tumor cells can be isolated from the blood stream and characterized. The original application of the technology was a prognostic marker by which patients with breast, colorectal or prostate cancers and high levels of circulating tumor cells, fell in the “high-risk” groups. I have been highly supportive of the application of this technology and have applied it extensively for patients with prostate and breast cancers.

The more recent iteration of this technique will allow investigators to not only identify but also characterize the isolated tumor cells. This provides an exciting new opportunity for early diagnosis.

As we speculate on the ramifications of this discovery, certain questions are raised. The most immediate being: What to do with the data? It has previously been suggested that many cancers arise 20 or 30 years before they are clinically detected. Malignant populations measuring in the hundreds of thousands, millions or even hundreds of millions, may still lie below the radar screen of modern diagnostic tools. If we have the capacity to identify patients 10 or 20 years before their cancers can be clinically detected, would we then begin therapy decades before clinical disease arises? If so, what treatments will we administer? Will the early detection of cancer cells be associated with the further characterization of tumors, such that targeted agents can be utilized to eliminate these clones at their earliest inception?

We will watch the development of these clinical studies with great interest. It will be even more interesting to see how we answer the questions that arise.