DURHAM, NC -- Duke University researchers report that a common surgery used to determine the extent of disease in early stage breast cancer patients may not benefit a large number of them.
Axillary lymph node dissection, the removal of underarm lymph nodes that drain fluids from breast tissue, has been a mainstay of breast cancer treatment. Physicians used the findings to plan treatments based on whether the cancer had spread to the nodes, and to how many of the nodes. In fact, a patient's "stage" of disease depends in part on the findings.
But the Duke researchers found that information gained from this surgery, which often leaves a patient with scars and nerve damage, is not always crucial, given new ways of combating breast cancer. Knowing lymph node status was also unlikely to affect survival, they concluded in a study published in the May issue of the Journal of Clinical Oncology.
"Patients with positive nodes used to be treated differently than patients with negative lymph nodes," explained study author Giovanni Parmigiani, associate professor in the Institute of Statistics and Decision Sciences at Duke.
"Lately, research has been changing the recommendations for adjuvant therapy. If the information obtained through axillary lymph node dissection isn't as valuable for these patients, we should seriously consider reassessing its purpose."
Supported by the Duke Specialized Program of Research Excellence (SPORE) in Breast Cancer award from the National Cancer Institute, the research team developed a decision model to systematically evaluate axillary lymph node dissection in early stage breast cancer patients whose nodes were normal on physical exams. The researchers combined the results of numerous recent clinical trials along with information about cancer rates and survival to determine what benefit lymph node status provided. The results were quantified in terms of additional life expectancy, taking into account quality of life as well.
They found that the newer ways of treating breast cancer, such as recommending chemotherapy for early as well as late stage disease, superceded information gained from removing and analyzing lymph nodes in most cases. Physicians also now routinely prescribe the drug tamoxifen to treat tumors with estrogen receptors, regardless of node status. These methods are quite different than those available when axillary lymph node dissection studies initially took place, Parmigiani said.
The biggest benefit of axillary node dissection surgery is for estrogen receptor positive women with small tumors who can avoid chemotherapy if their lymph nodes are actually negative, Parmigiani said, but the benefit is small. For other patients, the statistical analysis showed that chemotherapy plus tamoxifen, if indicated, was the preferred treatment, regardless of node status.
"If an early stage patient is undergoing breast-conservation surgery and having radiation, our model shows that axillary lymph node dissection shouldn't be a routine procedure," he said. "It is important for physicians to consider how therapy would be changed by the results of the procedure, and to discuss with their patients whether the prognostic information alone is worth the surgery."
At first, axillary lymph node dissection was thought to improve survival by removing the first site of cancer spread. But studies showed that it wasn't more effective than non-surgical options such as radiation.
The procedure also was used to help understand what additional therapy to use -- radiation, chemotherapy, or both. But its role in determining treatment options is now being reconsidered in clinical trials, Parmigiani said.
Axillary lymph node dissection still provides prognostic information. Lymph node status indicates if the cancer has spread, and some women need to know what they are facing, even if knowing in and of itself doesn't provide any survival advantages, Parmigiani said.
In some studies, axillary lymph node dissection is being compared to less invasive sentinel node biopsy, in which radioactivity or a dye is used to identify which specific nodes are the first stop from the site of the tumor. These nodes are then analyzed for cancer cells. The Duke decision model does not consider sentinel node biopsy, Parmigiani said.
Co-authors on the study are Donald Berry of Duke University, Dirk Iglehart and Leonard Prosnitz of Duke Comprehensive Cancer Center, Eric Winer of Dana Farber Cancer Institute in Boston, and Claudia Tebaldi of the National Center for Atmospheric Research in Boulder, Colo. All researchers were at Duke when the study took place.
Journal
Journal of Clinical Oncology