Any spread of breast cancer raises risk of return

Breast cancer patients with even the tiniest spread of the disease to a lymph node have a much higher risk of it recurring years later and may need more treatment than just surgery, new research 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 new study 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 Dr. Linda Vahdat, director of breast cancer research at Weill Cornell Medical College and an adviser for the breast cancer patient Web site of ASCO, the American Society of Clinical Oncology.

Results are in the current New England Journal of Medicine.

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 to others who were not treated. The study also was done at a time when treatment was less aggressive and in the Netherlands, where doctors had been treating breast cancer more conservatively than in the United States.

In the U.S., many women with early stage breast cancer are given hormone blockers.

"The big issue is, should these patients also get chemotherapy?" Dr. Daniel Hayes, director of breast cancer treatment at the University of Michigan, said.

The Dutch study involved more than 2,700 women with low-risk, early stage cancer. 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. Doctors do this by examining tissue slices from the nodes and using special stains to make cancer cells show up.

Larger tumors in lymph nodes already trigger further treatment. A micro tumor is a cluster of cells less than 2 millimeters - smaller than one-tenth of an inch. Most, but not all, doctors would treat these, too. Isolated tumor cells are even tinier and do not typically spur further treatment under current guidelines.

In most cases, breast cancer doesn't 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 was 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.