If Sentinel Lymph Node Is Positive, Then Standard Lymph Node Surgery Is Necessary

Reviewed study: "If Sentinel Lymph Node Is Positive, Then Standard Lymph Node Surgery Is Necessary" by T. B. Julian and others, San Antonio Breast Cancer Symposium, December 9, 2005, Abstract 20

Is this for me? If you've been diagnosed with breast cancer and are unsure which type of lymph node surgery you should have, you might want to read this article.

Background and importance of the study: When a woman is diagnosed with breast cancer, it's important to know whether breast cancer cells have spread to the underarm (axillary) lymph nodes near the affected breast. Fluid from the breast drains into the armpit, and the lymph nodes filter that fluid. If cancer cells are found in one or more lymph nodes, there's a higher risk of the cancer coming back in other parts of the body. So the information that comes from lymph node removal helps you and your doctor decide on the best treatment for you. Removing involved lymph nodes also helps keep the lymph node area cancer-free.

If cancer cells are found in the lymph nodes, your test results are called "positive." If cancer cells are not found in the lymph nodes, your test results are called "negative."

The standard way to remove lymph nodes (called axillary lymph node dissection) is to remove a pad of fat along the bundle of blood vessels and nerves from the armpit. The removed fat contains about a dozen lymph nodes. A pathologist looks carefully at the nodes under the microscope.

A newer way to detect cancer cells in the lymph nodes, called sentinel lymph node dissection, may be used for women who have no lymph node enlargement of concern that can be felt by physical examination or seen on tests before surgery. The "sentinel" node, the one closest to the breast, is the "watchdog" node that's responsible for filtering out cancer cells that may have escaped from the breast and are heading toward the armpit. Your surgeon wants to be sure to remove this lymph node because it's the most likely lymph node for the cancer to travel to. Sometimes there's more than one sentinel lymph node.

In sentinel lymph node dissection, the surgeon injects a blue dye, a radioactive substance (tracer), or both into the area around the cancer or behind the nipple. The dye or tracer follows the path that the cancer cells would most likely take from the breast area to the lymph nodes. The surgeon then removes the sentinel node (or sometimes the first few nodes) — the one (or ones) that takes up most of the dye or tracer. Nodes near the sentinel node also may be removed.

The lymph nodes are examined under a microscope. If they contain cancer cells, then your surgeon might recommend doing a standard lymph node removal to check for additional areas of cancer. If a significant number of cancer cells are found in the lymph nodes, additional lymph nodes are usually removed. If only a few cancer cells are seen, your doctor may advise against more surgery.

But if the sentinel node is free of cancer cells, no more nodes are removed.

The standard axillary lymph node procedure removes more tissue and requires more work around the blood vessels and nerve bundles than sentinel lymph node removal. Research has shown that sentinel node removal causes fewer side effects than the standard axillary lymph node procedure. But the long-term chance of staying cancer-free if only a few nodes are removed is unknown.

In the study reported here, researchers looked at:

• whether finding cancer cells in the sentinel node means a woman must then have standard lymph node removal
• whether having a positive sentinel node—together with other factors—can predict the presence of cancer cells in the other lymph nodes

Study design: This study involved 5,611 women diagnosed with breast cancer who had no physical signs that the cancer had spread to their lymph nodes when their doctors examined them. The women were randomly assigned to one of two groups:

• The first group had sentinel lymph node removal immediately followed by axillary removal.
• The second group had just sentinel lymph node removal. If the sentinel node was positive, more nodes were removed using the standard procedure. If the sentinel lymph node was negative, no axillary surgery was done.

This study, part of the National Surgical Adjuvant Breast and Bowel Project, is called NSABP B-32.

Results: Women were significantly more likely to have at least one positive non-sentinel node if:

• their cancer was larger
• they have more positive sentinel nodes
• they had more non-sentinel nodes removed

The percentage of women with at least one positive non-sentinel node significantly decreased as the number of sentinel nodes removed increased.

Significant findings mean findings that are most likely NOT due to chance.

Some factors had no effect on whether positive non-sentinel nodes were found:

• the women's age
• the grade of the cancer
• hormone receptor status

Conclusions: The researchers concluded that most women who have sentinel lymph node removal that shows lymph node involvement should then have standard (axillary) lymph node removal.

The researchers found that other factors helped predict whether other, non-sentinel nodes were found.

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