Updated

LONDON (AP) — Some breast cancer patients may do just as well with a less invasive surgery to remove selected lymph nodes rather than the aggressive operation normally used to remove them all, a new study says.

In the biggest trial yet to compare the two procedures, North American researchers found early breast cancer patients don't need the more interventionist surgery to live longer.

Most patients with such cancer have surgery to remove the disease. Doctors sometimes decide to get rid of all the lymph nodes to better control the cancer because if the disease spreads, it usually goes first to the nearby lymph nodes. Experts also think there is a relationship between the number of lymph nodes affected and how aggressive a cancer is.

But the invasive operation, an axillary-lymph node dissection, often comes with nasty side effects like nerve damage and reduced use of the arms and shoulders.

Doctors can use another surgery to remove only the first set of lymph nodes, or the sentinel lymph nodes under the arm, but many physicians have assumed the more aggressive surgery gives women a better shot at staying alive.

The study dealt only with victims of early breast cancer, not women needing a mastectomy.

U.S. and Canadian scientists monitored 5,611 early breast cancer patients whose disease had not yet spread to their lymph nodes. About half were assigned to get both surgeries. The other half had operations to remove only some of their lymph nodes. Most patients in both groups also received other treatments like radiotherapy.

After tracking the patients for eight years, doctors didn't find any difference in the patients' survival rates.

Among the 1,975 women who got both surgeries, 1,660 were alive after eight years. Among the 2,011 who only got a few lymph nodes removed in the less invasive operation, 1,675 were alive.

The study was paid for by the U.S. Public Health Service, the National Cancer Institute and the Department of Health and Human Services. It was published Tuesday in the journal Lancet Oncology.

"This is good for patients because this is a less aggressive technique which could mean fewer patients develop unpleasant side effects (like major tissue swelling)," said Meg McArthur, a senior policy officer at the British charity Breakthrough Breast Cancer. She was not linked to the paper.

John Benson of Cambridge University called it a "seminal" paper that should help treat most early stage breast cancer patients. He also was not linked to the research.

"It will now be difficult to justify (using aggressive surgery) when there is no marked difference in survival," he said, adding there may be some cases where using the more invasive procedure is preferable, such as if patients have larger tumors or more advanced disease.

Benson said all breast cancer patients need to be carefully monitored after their surgeries. He noted in the study that of the women who had the less invasive procedure, 14 had cancer return in the region of their lymph nodes compared to eight of those who had the more aggressive surgery.

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Online:

www.lancet.com

www.breakthrough.org.uk