Clinical relevance of minimal residual cancer in patients with solid malignancies

With the advent of new therapeutic modalities, the treatment options for on cologists can vary greatly depending upon the aggressiveness of the patient 's cancer. Patients may receive no therapy, adjuvant therapy, aggressive ad juvant therapy (taxane based), monoclonal antibody therapy (e.g. Herceptin) or bone marrow transplantation. It is now mandatory to determine accurate prognostic patient profiles at diagnosis and during therapy to determine wh o would benefit most from a particular therapeutic regimen or to determine who should be shifted into more aggressive therapy. We now have ultra-sensi tive methods of tumor cell detection that can determine the presence of min imal residual cancer (MRC) in marrow, stem cell product (SCP) and lymph nod e to help create these prognostic profiles. The author has conducted a crit ical review of the literature regarding the type of testing used to detect MRC, the incidence of MRC in marrow, SCP, and lymph node, and the clinical significance of MRC at diagnosis and during therapy. To date it is now clear that immunohistochemistry is a very useful diagnost ic tool with adequate sensitivity to detect MRC. The presence of MRC at dia gnosis in marrow and/or lymph node is associated with a poor prognosis for a number of disorders including breast cancer, neuroblastoma, gastrointesti nal tumors, and lung cancer. In addition, the presence of MRC during therap y in marrow and/or SCP is associated with a very poor prognosis for patient s with breast cancer. The use of testing for MRC in the patient provides pr ognostic information that may be of use to the oncologist.