Detection of circulating solid tumor cells by reverse transcriptase polymerase chain reaction

Despite advances in cancer treatment, disseminating disease continues to pose a major problem in clinical management. The dissemination of cancer cells around the body, or metastasis, involves multiple tumor-host interactions. The relatronship between circulating tumor cells and development of secondary disease is not fully understood, though for cells to metastasize they must be capable of entering and surviving in peripheral blood or bone marrow. Although it is thought less than 0.01% of cnculating tumor cells will successfully establish metastatic colonies (1) detect small numbers of such cells will allow evaluation of their role in the disease process. This may provide the clinician with a powerful tool to predict recurrence and relapse. In the longterm this may lead to improved clinical outcome by additional treament of persistent disease following conventional therapy or early intervention in patients with micrometastatic disease and preclinical relapse.