Surgery to Remove Sentinel Lymph Nodes With or Without Removing Lymph Nodes in the Armpit in Treating Women With Breast Cancer

RATIONALE: Removing the sentinel lymph nodes and examining them under a microscope may help plan more effective surgery for breast cancer. It is not yet known if surgery to remove the sentinel lymph nodes is more effective with or without removal of the lymph nodes in the armpit in treating breast cancer. PURPOSE: Randomized phase III trial to compare the effectiveness of surgery to remove the sentinel lymph nodes with or without removal of lymph nodes in the armpit in treating women who have breast cancer.