Uneven use of less-invasive breast cancer staging test reported

Mar 26 2008

The use of sentinel lymph node biopsy (SLNB) during breast cancer surgery increased substantially from 1998 through 2005, according to an article published online March 25 in the Journal of the National Cancer Institute.

However, non-white women, older women, and those living in poorer areas of the U.S. were less likely to receive SLNB than their counterparts who are white, younger, or from more affluent areas, respectively.

A key prognostic factor for breast cancer is whether or not the disease has spread beyond the breast tissue into neighboring lymph nodes. To look for such invasion, surgeons can remove many lymph nodes in a procedure called axillary lymph node dissection (ALND) or only a few in the SLNB procedure. In 1998, clinical care guidelines changed, allowing surgeons to use SLNB for certain patients. SLNB is associated with easier recovery and fewer long-term problems for patients than ALND.

In the current study, Amy Y. Chen, M.D., of Emory University and the American Cancer Society in Atlanta and colleagues examined patient data from a national hospital-based cancer registry to determine how frequently SLNB had been used between 1998 and 2005. They also looked at whether patient-related factors or the type of treatment facility affected a woman's chance of receiving SLNB over ALND.

The researchers identified 490,899 women in the National Cancer Database who underwent breast cancer surgery during the study period and had a stage of disease for which SLNB would be appropriate. The proportion of these patients who underwent SLNB increased from 26.8 percent to 65.5 percent during the study period. However, not all women were equally likely to undergo SLNB. Non-white women, women aged 72 years or older, and those who lived in zip code areas that had a lower proportion of high school graduates or lower median incomes were less likely than women who were white, younger, or from more educated or affluent regions to undergo SLNB. Disparities between these groups persisted from 1998 through 2005. For example, in 1998, 29 percent of white women received SLNB, compared with 26 percent among African American women and 35 percent among Hispanic women. In 2005, these rates rose to 70 percent, 64 percent, and 67 percent, respectively.

The clinical guidelines recommend that SLNB only be performed in facilities that have teams experienced with the procedure. While the use of SLNB increased over time in all types of hospitals, data were not available to assess whether disparities in access to SLNB were related to lack of experience with the procedure in facilities that were treating poorer women.

“The disparities that were related to receipt of SLNB in this study are particularly important in light of the clinical advantages associated with this technique. Better outcomes have been reported for patients receiving SLNB than for patients receiving ALND,” the authors write.

In an accompanying editorial, Stephen B. Edge, M.D., of Roswell Park Cancer Institute in Buffalo, N.Y., describes the history of sentinel lymph node biopsy and its rapid acceptance among breast cancer surgeons. The incorporation of the technique preceded outcome data from large randomized trials. In this instance, such enthusiasm appears to have been well placed, he writes, but a more cautious approach with new interventions should be observed in general.

Despite the eagerness of surgeons to use the technique, not all patients have equal access to the less invasive approach. “Given America's track record of disparate care, I suppose we should not be surprised that racial and ethnic minorities were disproportionately deprived of another medical advance. However, this observation is profoundly disappointing and sobering. It is yet another call for us to redouble efforts to identify and correct the root causes of disparities,” Edge writes.