NEW ORLEANS—A considerable proportion of patients with primary breast cancer have minimal residual disease in the bone marrow that is prognostically relevant and detectable by bone marrow aspiration, according to German investigators who reported their findings at the 92nd Annual Meeting of the American Association for Cancer Research (AACR).

The results of the studies do not have immediate therapeutic implications, but they add to a growing concern that patients who appear to have a favorable prognosis may actually be headed for metastatic disease.

"The message is that we may be treating some patients in error or some not at all who are at increased risk," said Wolfgang Janni, MD, of Ludwig-Maximillians University, I. Frauenklinik, Munich, Germany. The director of the I. Frauenklinik is Professor Dr. G. Kindermann.

Dr. Janni’s trial (abstract 204) examined the fate of occult metastatic cells detected in the bone marrow at the primary diagnosis of breast cancer and at a second aspiration at a later time. The aim was to determine whether outcome was affected by the presence of these occult metastatic cells on one aspiration or both (persistently positive).

Cytokeratin Positivity

The study included 89 patients with stage I-III breast cancer who were free of recurrence. Bone marrow aspirates taken at diagnosis and after a median interval of 19 months (range, 7 to 67 months) were analyzed for cytokeratin positivity. The patients then were followed prospectively for a median of 41 months (range, 12 to 78 months) after the first bone marrow aspiration.

At the time of primary breast cancer diagnosis, 24 of 89 patients presented with occult metastatic cells in the bone marrow. At the second aspiration, 50 patients remained negative for occult tumor cells; 10 patients remained positive; 15 became newly positive; and 14 who were initially positive became negative (see Table), Dr. Janni reported, along with Christian Schindlbeck, MD, and their colleagues.