Radiation to Axillary Lymph Nodes Causes Less Lymphedema Than Surgery

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A study has found that women diagnosed with early-stage breast cancer are less likely to have lymphedema if they get radiation to their axillary lymph nodes instead of having them surgically removed.

The study, the AMAROS trial, was presented at the 2013 European Cancer Congress on Oct. 4, 2013. Read the abstract of “Axillary lymph node dissection versus axillary radiotherapy; A detailed analysis of morbidity. Results from the EORTC 10981-22023 AMAROS trial.”

When early-stage breast cancer is removed, the lymph node closest to the cancer -- called the sentinel node -- often is removed and sent to a pathologist for evaluation. Removing just this one node is called sentinel node biopsy or sentinel node dissection.

If cancer cells are in the sentinel node, it means the cancer has spread beyond the breast. In the past, doctors thought that more treatment might be needed to reduce the risk of the cancer coming back (recurrence), including:

  • removing other underarm lymph nodes (axillary node dissection)
  • radiation therapy to the underarm lymph nodes (axillary radiation)
  • chemotherapy
  • hormonal therapy if the cancer is hormone-receptor-positive

But research has shown that women diagnosed with early-stage breast cancer with a positive sentinel node who have no further treatment do just as well as women who have axillary node dissection. They also had a lower risk of lymphedema. The AMAROS trial results also support the idea that no more surgery is needed if the sentinel node is positive: the researchers found that axillary radiation causes less lymphedema than axillary surgery. Results from this same study presented in July 2013 at the American Society of Clinical Oncology Annual Meeting also found that axillary radiation reduces recurrence risk about the same amount as axillary lymph node surgery.

Lymphedema is the swelling of the soft tissues caused by a build-up of lymph fluid. Depending on the type of surgery and other treatments a person has, it’s possible for lymphedema to occur in the arm, hand, breast, trunk, or abdomen. The swelling can be accompanied by pain, tightness, numbness, and sometimes infection. Lymphedema can happen days, months, or years after breast cancer treatment and can be temporary or ongoing. Because lymphedema can be misdiagnosed or overlooked in mild cases, it’s difficult to know exactly how many women are affected. Experts estimate that 20-30% of women will have some type of lymphedema after breast cancer surgery.

In the AMAROS trial, about 1,400 women diagnosed with early-stage breast cancer who had positive sentinel node biopsy results were randomly split into two treatment groups:

  • one group had axillary node dissection (744 women)
  • the other group had axillary radiation daily 5 days a week for 5 weeks (681 women)

Some of the women had both axillary node dissection and axillary radiation.

The two groups were similar in terms of age, cancer size and grade, cancer characteristics, and whether the women got other treatments after surgery. The researchers assessed any lymphedema at 1, 3, and 5 years after surgery for both groups of women.

After more than 10 years of follow-up, the rate of lymphedema in women who had axillary node dissection was:

  • 25.6% at 1 year
  • 21% at 3 years
  • 20.8% at 5 years

The rate of lymphedema in women who had axillary radiation was:

  • 15% at 1 year
  • 13.4% at 3 years
  • 10.3% at 5 years

This difference was significant, which means that it was likely because of the difference in treatment and not just due to chance.

Women who had both axillary node dissection and axillary radiation had the highest rates of lymphedema:

  • 59.3% at 1 year
  • 44.8% at 3 years
  • 58.3% at 5 years

Women who had axillary dissection also had more complications from surgery, including bleeding, infection, and seroma (a build-up of lymph fluid under the skin near the surgical site):

  • 29% of the women who had axillary node dissection had surgical complications
  • 9% of the women who had axillary radiation had surgical complications

The results of this study are very positive and give us more evidence that no more surgery is needed if cancer is found in the sentinel node of a woman diagnosed with early-stage breast cancer.

If you’ve been diagnosed with early-stage breast cancer, sentinel node biopsy may be done as part of your surgery. If cancer cells are found in the sentinel node, your doctor will consider all the details of your situation, including your age and the characteristics of the cancer (size, stage, etc.) before recommending treatments to reduce the risk of recurrence.

You can learn more by visiting the Breastcancer.org Lymph Node Removal pages.

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