Causes of Lymphedema? More Than Surgery, It Turns Out

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Studying lymphedema can be difficult because it may not develop until years after its cause. However, by looking at the medical records of 1,794 patients diagnosed with breast cancer in Olmstead County, Minnesota, between 1990 and 2010, researchers at the Mayo Clinic were able to get a better understanding of the multiple factors that can affect the onset of lymphedema in breast cancer survivors. The data was presented at the 2017 American Society of Breast Surgeons Annual Meeting.

A chronic condition

Lymphedema is a chronic condition characterized by swelling when the lymphatic system doesn’t work properly. While it may be hereditary (primary lymphedema), often it is caused by trauma to the lymph nodes in a specific area of the body (secondary lymphedema). For breast cancer patients, the swelling usually occurs in the trunk or arm on the cancer side. It may not occur until years after cancer treatment.

Many women diagnosed with breast cancer are aware that surgery removing the lymph nodes under their arms may increase the possibility of developing lymphedema, but few are aware that radiation can also increases their risk. This research at Mayo Clinic shows that chemotherapy, especially with taxanes, and obesity, also increase risk.

Does sentinel node biopsy help?

One advance in breast cancer surgery was the sentinel lymph node biopsy, developed in 1992, which allows doctors to inject dye into a patient’s breast to see which lymph nodes it reaches first. Then the surgeon removes just those first lymph nodes. If patients do not have cancer cells, doctors feel confident that the cancer has not spread to the other lymph nodes. Doctors expected that sentinel node surgery would reduce lymphedema, and in this Mayo Clinic research, led by Judy C. Boughey, M.D., it did to some extent. Sentinel node patients had a 5.3 percent rate of lymphedema compared to 15.9 percent for patients who had most or all of the lymph nodes under their arms removed. However, this difference did not hold up for the 453 patients whose treatment was just surgery. Rates for those patients were similar at near 4 percent.

More than surgery affects lymphedema

So what raises lymphedema rates? Radiation was a big factor in this research. Almost a third of patients who received axillary (under the arm) radiation developed lymphedema within five years. Many women choose breast conserving surgery plus radiation instead of a mastectomy in the hopes of avoiding lymphedema. This study should give people new data to consider when making that decision. While there are other reasons to decide on a lumpectomy rather than a mastectomy, it seems to me that this research does not support treatment with lumpectomy plus radiation as a way to avoid lymphedema.

Chemotherapy also raised lymphedema rates. More than a quarter of patients who received chemotherapy had lymphedema, compared to 6 percent who did not have it. This might surprise some who thought chemotherapy did not cause lymphedema, but this research shows otherwise.

Body mass was also a predictor for lymphedema. A body mass index (BMI) of over 35 correlated with higher lymphedema rates. Patients with a BMI less than 25 had an 8 percent risk at five years, compared to a 17.1 percent risk for those over 35 BMI.

The more risk factors a patient had, the higher her chances of getting lymphedema. Patients who had axillary lymph nodes removed, with radiation and chemotherapy, had lymphedema rates of more than 40 percent in this study.

This was a fairly large study done over a long period of time, so it was able to capture lymphedema cases that developed years after treatment.

One limitation of the study to keep in mind is that Olmstead County is mainly white, educated, and affluent, so factors affecting minority patients or patients with lower education levels may have been missed. For example, are lymphedema rates higher for women whose work involves repetitive motion like hair stylists or clerical workers? Would their lymphedema rate be even higher than 40 percent?

What can you do?

I’m one of those people who had multi-modality treatment that put me at high risk for lymphedema, but I wouldn’t make any different treatment choices. When a doctor is recommending surgery, chemo, and radiation, it is to save a person’s life. Lymphedema becomes a secondary concern. However, the researchers suggest that those at high risk for lymphedema should be evaluated at a lymphedema clinic and closely monitored over the years. Early treatment of mild lymphedema is important to prevent this chronic condition from getting worse.

It would be a good idea for you to ask for an appointment with a lymphedema therapist if you have had multi-modality treatment. A lymphedema expert can take baseline measurements on your arm and offer you suggestions on how to avoid actions that might trigger swelling. Most breast cancer patients will never get lymphedema, but it is sensible to take precautions against it.

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