Spreading Breast Cancer Carries Risk Of Return
Research indicates that the smallest spread of cancer to a lymph node can put a breast cancer patient at much higher risk of having the disease return years later, suggesting more treatment than surgery may be needed.
Doctors and patients have been tormented for years with the decision of what action to take when a microscopic tumor or stray cancer cells in a lymph node are found.
When women are diagnosed with "micro tumors", they are typically given estrogen-blocking drugs, chemotherapy or both. Women with isolated cancer cells do not usually take such measures, since these cells were not previously considered to be as concerning.
However, the new study challenges that view. It suggests that no matter how the cancer spreads, the chance of a woman having the cancer reappear in the breast or elsewhere in the following five years is 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.
She said, "I think it will influence treatment”¦if we’re considering treating the patient, we probably should."
Dr. Daniel Hayes, director of breast cancer treatment at the University of Michigan, agreed. He said, “It really does look like our biases are wrong."
"For the first time, it suggests that isolated tumor cells or micro-metastases do have biological significance."
Vahdat and Hayes had no connection to the study, which was performed by researchers throughout the Netherlands. Results are in Thursday’s New England Journal of Medicine.
The study did not have the most ideal conditions. It only observed a large number of women rather than assigning them to groups where some would receive treatment and then compare their results to those who were not treated.
Another downfall of this particular study is that it was performed during a time when treatment was less aggressive and in a country where doctors were known to be more conservative with their treatment than in the United States. Many women with early stage breast cancer in the U.S. are given hormone blockers.
"The big issue is, should these patients also get chemotherapy?" Hayes said.
But not all women would benefit from chemotherapy even with a high risk of recurrence, according to Dr. 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.
Over 2,700 women with low-risk, early stage cancer, such as small tumors that did not seem aggressive participated in the Dutch study. All had surgery to remove their breast tumors.
The doctors removed all of their armpit lymph nodes or a few key "sentinel" nodes and checked them for signs of cancer by examining tissue slices from the nodes and using special stains to make cancer cells appear.
More in depth treatment is automatically encouraged for larger tumors in lymph nodes. A micro tumor is a cluster of cells less than 2 millimeters, which is smaller than one-tenth of an inch. Almost all doctors would treat these as well. Isolated tumor cells are even smaller.
“You can essentially count them" in a tissue sample, Winer said. And current guidelines do not typically require further treatment of them.
The Dutch researchers did a comparison of patients based on whether they received treatment beyond surgery and whether various levels of cancer was found in a lymph node.
The breast cancer does not come back after surgery in most cases. Of the women in the study who were given no additional treatment, 86 percent with no cancer in lymph nodes remained cancer free five years later.
Only 76 percent of those with micro tumors and 77 percent of those with isolated cancer cells were cancer-free.
This means a 50 percent greater risk of recurrence if any sign of cancer was present in a node.
Women with micro tumors or stray cells who were given additional treatment also had a 43 percent lower risk of a cancer recurrence than similar women who received no treatment beyond surgery.
The disparity between the two groups should encourage doctors to reconsider guidelines for how tumors are classified. This would guide the amount of treatment a woman receives, the authors write.
Micro tumors are now considered "node positive" cancer, requiring further treatment, while isolated cells are called "node negative."
Hayes said that a new version of the guidelines is expected to be released soon.
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