Try explaining this to a clinician: The patient is N0 but is POSITIVE for isolated tumor cells in two out of three sentinel axillary nodes and, by the way, they were only found with IHC for cytokeratins. This is a controversial area (to say the least) in terms of what to do with the patient. Should the patient have a completion axillary dissection? Adjuvant chemotherapy? Additional testing, e.g., OncotypeDX?
A recent meta-analysis published in Journal of the National Cancer Institute in November 2008 "Non-Sentinel Lymph Node Metastases Associated with Isolated Breast Cancer Cells in the Sentinel Node" might be helpful in assessing these patients. We have seen several such patients over the past year or so and this article probably underestimates the prevalence of this situation. The article suggests that the presence of ITCs in a sentinel node without other indications for adjuvant chemotherapy might benefit from axillary lymph node dissection for staging.
This is probably a half-step behind current practice but would like to hear what is happening at your places. The use of Adjuvant Online and OncotypeDX has been my experience before consideration of axillary dissection. It seems oncologists (and surgeons?) are looking for any alternatives to complete dissection to spare the patients the additional morbidity.