NEW YORK, Sep 10 (Reuters Health) -- A new technique for examining cells from lymph nodes under the microscope can improve the detection of breast cancer that has spread to armpit nodes, say researchers.
The international team suggests that the technique, called immunohistochemical detection, aids in the diagnosis and staging of breast cancer, and should become "a standard method of node examination in postmenopausal patients," according to their report, published Saturday in The Lancet.
Staging a cancer, that is, determining how far it has spread, has important implications for treatment and survival. Breast cancer often spreads first to armpit lymph nodes under the arm on the same side of the body as the affected breast.
The findings mean that currently used standard methods of examining tissues to assess the status of the lymph nodes in breast cancer patients are outdated, according to Dr. R.J. Cote from the University of Southern California School of Medicine in Los Angeles, and colleagues with the International Breast Cancer Study Group.
Immunohistochemistry relies on a specific immune reaction between a special stain and breast cancer cells that causes a chemical change that can be spotted under the microscope, the investigators report.
The immunohistochemical method was nearly three times as sensitive as standard tissue staining methods. Among 736 breast cancer patients studied, the standard method detected lymph node spread (metastases) in 52 patients (7%), while the immunohistochemical method detected metastases in 148 (20%), the results indicate.
Also, the new technique was more sensitive than the standard method in detecting lymph node metastases regardless of the type of breast cancer, the researchers note.
"Overall, patients with (lymph node) metastases detected had significantly worse survival than the node-negative group," the authors write. Survival diminished as the number of tumor cells detected in lymph nodes increased.
In postmenopausal patients, the presence of breast cancer cells in a lymph node predicted shorter overall survival and higher likelihood of recurrence, the investigators indicate.
Cote and colleagues conclude that the immunohistochemical method provides a reliable, simple means of detecting breast cancer cells hidden in lymph nodes.
