Assessing the risk of recurrence in breast cancer

The search for ever better methods of predicting the prognosis of a cancer patient is at the forefront of today's cancer research. An article in the February 1, 1990 issue of 'The New England Journal of Medicine' presents the results of assessing the risk for the recurrence of breast cancer by a relatively simple test. The ability to predict which patients with breast disease are likely to be at high risk for cancer recurrence would be important in planning clinical treatment. In 1979, a glycoprotein (combination of protein and carbohydrate) was identified as being secreted by human breast cancer cells grown in laboratory tissue cultures. After purification this molecule, called cathepsin D, was identified as a precursor of an enzyme which acts to break down protein (i.e., a protease). This compound was found to be stimulated by the level of female hormones or estrogens, and its level was restricted by anti-estrogen drugs (which oppose estrogens). A classification system for the prognosis of breast cancer patients is related to the degree of cancerous involvement of the lymph nodes; an absence of lymph node involvement is associated with a better prognosis, and the occurrence of lymph node involvement is related to a poorer prognosis. The possibility that cathepsin D is important as a prognostic factor is interesting because it is stimulated by estrogens and many breast cancers also have receptors for estrogens. In the reported research, the value of cathepsin D for predicting the rate of breast cancer recurrence is explored in a study of 396 women. Overall survival was better for all patients who had low levels of cathepsin D; however, the predictive values were much greater for women who were node-negative (no involvement of the lymph nodes). The work appears to be promising, but both patients and physicians alike should proceed carefully until the utility of this test is completely explored in routine clinical practice. (Consumer Summary produced by Reliance Medical Information, Inc.)