Nonclinical factors affect odds of breast cancer patients having sentinel node biopsy

March 27, 2008

NEW YORK (Reuters Health) - The likelihood that a woman with early breast cancer will undergo sentinel lymph node biopsy -- as opposed to the more invasive axillary lymph node dissection -- depends in part on sociodemographic characteristics and insurance status, as well as clinical factors, according to a new study.

Better outcomes are associated with sentinel lymph node biopsy (SLNB) compared with axillary lymph node dissection (ALND), including decreased lymphedema and pain. According to Dr. Amy Y. Chen, with the American Cancer Society in Atlanta, Georgia, and colleagues, little is known about factors that influence the choice of procedure.

They examined these issues using the National Cancer Database, which covers facilities approved by the American College of Surgeons Commission on Cancer. Their study included 491,000 patients with T1a, T1b, T1c, and T2N0 breast cancer who received surgical treatment including lymph node sampling between 1998 and 2005.

The use of SLNB increased from 26.8% in 1998 to 65.5% in 2005, Dr. Chen and her colleagues report in the Journal of the National Cancer Institute for April 2.

According to multivariate analysis for the entire study period, independent risk factors for not receiving SLNB included age over 72 years, belonging to a racial/ethnic minority, and having Medicaid or no health insurance. Individuals residing in zip codes where more than 19% of residents had not graduated high school or where the median household income was less than $32,000 were more likely to receive ALND.

SLNB was performed significantly less often among patients with T2 disease, those who underwent mastectomy, and those treated at community facilities.

"SLNB is most appropriately done in conjunction with breast conserving surgery," Dr. Chen told Reuters Health. "Radiation is required after breast-conserving surgery, so if the physician decides that radiation is not 'do-able' after surgery, then a more comprehensive breast and lymph node surgery may be done, and thus ALND may be performed."

"SLNB is technically more involved, although not necessarily more difficult," she added. "If surgeons are not trained to do SLNB or if they work in facilities that do not have the support infrastructure, ie, radiology service, then they may need to do ALND."

The research team also examined trends over time and observed that, in contrast to disparities that existed in 2005, some factors, including older age, income, and health insurance status, were not associated with chances of undergoing SLNB in 1998. Disparities associated with minority status widened.

According to their paper, the adjusted annual rates of SLNB in 2005 were 0.70 in whites, 0.64 in African Americans, and 0.67 in Hispanics.

"Even when we controlled for low income and health insurance status, racial disparities still persisted," Dr. Chen added. "It is concerning to see that as dissemination of SLNB increased across all facility types, racial and socioeconomic status disparities increased."

However, because the database does not include individual hospital characteristics, she added, they could not tell if "disproportionate groups of poorer individuals, for example, seek medical care at facilities that do not offer SLNB."

These findings imply, the authors state, that "those who are more likely to receive ALND may lack resources to deal with the added burdens associated with its adverse effects."