A new computerized tool helps physicians calculate risk for breast cancer beyond the sentinel node and make decisions regarding complete axillary dissection, according to an article in the December issue of the Annals of Surgical Oncology.

In the first phase, American researchers developed the nomogram based on pathological features of the primary breast tumor and presence of sentinel lymph node metastasis in 702 patients. The nomogram was then used prospectively with 373 patients whose cancer was detected in biopsy of sentinel nodes; the investigators found that the prognostic tool (the computerized nomogram) predicted risk for axillary lymph node metastasis to within a few percentage points.

“This easy-to-use nomogram will allow patients and their physicians to obtain accurate estimates of a patient’s risk for additional disease in the axillary lymph nodes, and can assist greatly in individualized decision-making regarding further treatment,” said the study’s lead author Kimberly Van Zee, MD.

The nomogram takes several pathological factors into account, including tumor size, tumor type (ductal or lobular), estrogen-receptor status of the primary tumor, method of detection of sentinel node metastases (frozen section analysis, routine analysis, or enhanced pathologic analysis), and the number of positive and negative sentinel lymph nodes.

“There are many variables affecting the probability of additional lymph node metastasis, however, this nomogram represents the best prediction model currently available,” said the study’s senior author Michael Kattan, PhD.

Previous studies had shown that roughly 50 percent of women with disease in the sentinel lymph nodes have cancer in other axillary nodes. Consequently, the current standard of care for patients with sentinel-node disease includes surgical axillary lymph node dissection. Although axillary dissection does not affect survival, it does reduce risk for recurrent cancer in the axilla. Side effects of dissection include edema and infection.

Development of the nomogram gives physicians and patients one more information tool for use in deciding whether to proceed to axillary dissection. “Because the nomogram results make no actual treatment recommendations, we advise that patients discuss risk estimates with their doctor and consider which treatment options are most appropriate for their individual circumstances,” Van Zee said.

The breast cancer nomogram is available on the web site of Memorial Sloan Kettering Cancer Center, where it was developed: http://www.mskcc.org/nomograms/breastcancer