NEW YORK (Reuters Health) Sep 28 - Occult axillary lymph node metastases don't influence outcome in early breast cancer, researchers reported online August 25th in Cancer.

The subject "has been controversial, because some studies have demonstrated reduced survival when occult metastases were identified, and others have demonstrated no survival difference" - and when significant differences did show up, they were often too small to be clinically meaningful, said lead author Dr. Yun Wu and colleagues at The University of Texas MD Anderson Cancer Center, Houston.
Furthermore, because of different methodologies, studies can be hard to compare, the authors said.

For the current study they reviewed data on 267 patients who had axillary lymph node dissection between 1987 and 1995, with negative pathologic evaluations.

More recently, all of the dissected lymph nodes from these patients were re-evaluated by intensified pathologic methods and 39 patients (15%) were found to have occult metastases.

According to standard practice at the time, none of the patients received systemic chemotherapy or hormone therapy - which today makes it possible for Dr. Wu's group to analyze the natural history of occult lymph node disease.

Twenty percent of patients with occult lymph node disease had macrometastases (>2 mm), 40% had micrometastases (>0.2 mm to 2 mm) and 40% had isolated tumor cells (< 0. 2 mm).
Median follow-up for all patients was 15.7 years. Thirty patients (11%) died of the disease and 77 (29%) died of other causes. The median follow-up for patients who remained alive at the time of analysis was 17.8 years.

There was no difference in recurrence-free or overall survival between lymph node-negative patients and patients with occult metastases. There was also no relationship between survival and metastasis size.

The researchers note that this is in contrast to a recent report from Memorial Sloan-Kettering Hospital in New York that used similar methods. However, they point out that the Memorial study included patients with larger tumors, more metastases, and more patients with multiple involved lymph nodes.

The results from the current study, according to Dr. Wu and colleagues, "contribute further to the growing body of literature indicating that occult lymph node metastasis identified by intensified pathologic methods in patients with early stage breast cancer may not be biologically or clinically significant."

SOURCE: http://bit.ly/rkn1Nj
Cancer 2011.