Study spurs breast cancer rethink

Women with even the tiniest spread of breast cancer to a lymph node have a much higher risk of the disease recurring years later and may need more treatment than just surgery, a new study suggests.
For years, doctors and patients have struggled with what to do about a microscopic tumor or stray cancer cells in a lymph node. Women with "micro tumors" usually are given estrogen-blocking drugs, chemotherapy or both; those with isolated cancer cells usually are not, because those were thought to be of low concern.

The study - done in the Netherlands and published in the New England Journal of Medicine - challenges that view. It suggests that either type of metastasis, or spread, raises a woman's risk of having cancer show up in the breast or anywhere else in the next five years by about 50 percent.

"This took an area that was very gray and I think made it black and white," said Linda Vahdat, director of breast cancer research at Weill Cornell Medical College. "I think it will influence treatment."

Daniel Hayes, director of breast cancer treatment at the University of Michigan, agreed.

"It really does look like our biases are wrong," he said. "For the first time, it suggests that isolated tumor cells do have biological significance."

The study is not ideal: it just observed a large number of women rather than assigning some to get treatment and comparing how they fared with others who were not treated. The study also was done at a time when treatment was less aggressive and in a country where doctors treat breast cancer more conservatively than in the United States.

"The big issue is, should these patients also get chemotherapy?" Hayes said.

However, not all women benefit from chemotherapy even when their risk of a recurrence is high, said Eric Winer, breast cancer chief at the Dana-Farber Cancer Center in Boston.

"Patients are looking for more specific treatment" tailored to their individual tumor type - not necessarily more or less treatment, he said.

The study involved more than 2,700 women with low-risk, early-stage cancer - small tumors that did not seem aggressive. All had surgery to remove their breast tumors. All of their armpit lymph nodes or a few key ones called "sentinel" nodes were removed and checked for signs of cancer.

Larger tumors in lymph nodes already trigger further treatment. A micro tumor is a cluster of cells less than two millimeters. Most, but not all, doctors would treat these, too. Isolated tumor cells are even tinier and do not typically spur further treatment.

The Dutch researchers compared patients based on whether they received treatment beyond surgery and whether cancer of various amounts was found in a lymph node.

In most cases, breast cancer does not return after surgery. Among women in the study who were given no additional treatment, 86 percent of those with no cancer in lymph nodes were free of cancer five years later. Only 76 percent of those with micro tumors and 77 percent of those with isolated cancer cells were cancer-free. That translates to a roughly 50 percent greater risk of recurrence if any sign of cancer is present in a node.

Also, women with micro tumors or stray cells who were given additional treatment had a 43 percent lower risk of a cancer recurrence than similar women not treated beyond surgery.

The differences should lead doctors to reconsider guidelines for how tumors are classified, which guides the amount of treatment a woman receives. ASSOCIATED PRESS 
Source: http://www.thestandard.com.hk/news_print.asp?art_id=86329&sid=24890068