The incidence of some early stage metastatic breast cancers is increasing, but this finding is likely explained by changes in clinical practice, according to a study published online June 26 in the Journal of the National Cancer Institute. Deirdre Cronin-Fenton, Ph.D., of Aarhus University Hospital in Denmark, with colleagues at the National Cancer Institute in Bethesda, Md., found that the increase in some early stage breast cancers corresponded to greater use of biopsies of sentinel lymph nodes—the primary lymph node to which cancer cells are likely to spread from a tumor. Sentinel lymph node biopsies often detect small numbers of tumor cells that do not necessarily indicate that the cancer has spread.