The Terminology of “Carcinoma Cell Leukemia” — Is an Alternative Needed?

To the Editor:

I refer to the article of Nasr et al1 entitled “Carcinoma Cell Leukemia” published in a recent issue of Blood. I would like to express my reservation about the use of the phrase “carcinoma cell leukemia” to describe circulating carcinoma cells. Although it could be argued that the historical meaning of the word leukemia (Gr. leukos white + haima blood = white blood)2 may be applicable to conditions characterised by circulating cancer cells in peripheral blood, use of such terminology, in my opinion, may be a source for future confusion. In clinical practice, it is customary to use the terms leukemia and carcinoma to describe hematological malignancies and nonhematological malignancies, respectively. This distinction has clear advantages in that it differentiates the eminently treatable neoplasms of hematopoietic tissue from those of nonhematopoietic cells with very different biological behavior and prognosis. The distinction is particularly useful when counseling patients with leukemias who are terrified by the words carcinoma and cancer. The hybrid term “carcinoma cell leukemia” may blur this distinction, potentially leading to confusion. The term “carcinocytaemia”³ may be a preferable term because it is more accurately descriptive. My viewpoint may sound pedantic but I feel it is imperative that incorrect use of terminology should be discouraged to avoid creating confusion in the future.