The development of breast cancer-related lymphedema is tied closely to how many nodes are removed by surgery. Radiation therapy and chemotherapy can also increase risk. A recent study from Korea (published in (check out the length of the this name!) International Journal of Radiation Oncology Biology Physics, 2013) attempted to estimate the risk of lympededema based on combinations of these treatment factors.
The Study: The authors looked at 772 patients with breast cancer. All had primary surgery with axillary node dissection from 2004 to 2009. The study looked back at these patients (retrospective analysis). Adjuvant chemotherapy was given to 677 patients. Of the 675 who got radiation therapy, 35% had a component directed at the nodes above the collarbone (supraclavicular nodes).
Results: Half of patients were followed beyond 5.1 years. The 5 year cumulative chance of getting edema was 17%. Of these 76% developed it in the first 2 years after surgery. Fully 91% of those who got it did so within 3 years.
Risk factors included number of nodes removed by the surgeon, chemotherapy use, and whether the nodes above the collarbone were treated with radiation therapy. The total number of risk factors correlated well with the incidence of lymphedema. Patients with 0 to 1 risk factors had a 5 year risk of only 3%, while those with 2 or 3 risk factors had a risk of 19% and 38%, respectively.
My take: The bad news? Any lymph node removal introduces risk. The good news? If a patient had 10 of fewer nodes removed, and no other risk factors, the 5 year risk dropped to 1.4%. For those who had fewer than 10 nodes removed but got chemotherapy, the risk was 3.8%. Fortunately today, many patients who have a limited node sampling of only 1 to 3 nodes (to help establish prognosis for invasive breast cancer) have a very low risk of significant lymphedema. The so-called sentinel node procedure has truly improved the surgical management for many patients with early breast cancer. I’m Dr. Michael Hunter.
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