Most women with early-stage breast cancer avoid extensive lymph node removal

A new study of women with early-stage breast cancer finds that surgeons no longer universally remove most of the lymph nodes in the underarm area when a biopsy of the nearby lymph nodes shows cancer - a major change in breast cancer management. The study, which evaluated data from 2.7 million U.S. breast cancer patients, is published as an "article in press" on the Journal of the American College of Surgeons website in advance of print publication later this year.

Until now, it was unclear to what extent surgeons were following the recommendations of a landmark clinical trial published more than four years ago, known as the American College of Surgeons Oncology Group Z0011, or ACOSOG Z-11, trial. Those researchers reported that most early-stage breast cancer patients with tumor in their sentinel lymph node (the first draining node) who undergo lumpectomy do not benefit from surgical removal of the remaining lymph nodes in the underarm area, called completion axillary lymph node dissection (ALND). That study found no difference in cancer recurrence1 and five-year survival2 between patients who underwent ALND and those who did not but were monitored for recurrences.

The new study found a dramatic increase in the proportion of lumpectomy patients who underwent only a sentinel lymph node biopsy (SNB)--removal of the "gatekeeper" lymph nodes that the cancer is most likely to spread to first--without an ALND after discovery of cancerous sentinel nodes. According to the study authors, the SNB-alone rate more than doubled, from 23 percent in 2009, before publication of the first results1 of the ACOSOG Z-11 trial in September 2010, to 56 percent in 2011, the first year after publication.

"As far as I know, our study is the first to show that the findings from the ACOSOG Z-11 trial have changed clinical practice for breast cancer patients nationwide," said lead author Katharine Yao, MD, FACS, director of the Breast Surgical Program at NorthShore University HealthSystem, Evanston, Ill., and clinical associate professor of surgery at the University of Chicago Pritzker School of Medicine. "The Z-11 trial has had a huge impact because of the lower risks for patients who undergo SNB alone."

Removal of small numbers of lymph nodes in SNB alone, according to Dr. Yao, greatly lowers the lifetime risk of developing the often disabling complication of lymphedema. This buildup of lymph fluid under the skin results in swelling and sometimes pain.

For the new study, Dr. Yao and colleagues used the National Cancer Data Base (NCDB), a joint project of the American College of Surgeons Commission on Cancer (CoC) and the American Cancer Society. NCDB captures an estimated 70 percent of newly diagnosed cancer cases in the United States from approximately 1,500 cancer programs accredited by the CoC.

Although NCDB does not identify the type of lymph node dissection (SNB or SNB plus ALND) performed, the researchers used the number of lymph nodes removed as surrogates for these procedures. They categorized the removal of four or fewer lymph nodes as SNB only and removal of 10 or more nodes as ALND.