Lymph Node Radiation, Surgery Offer Similar Outcomes After Positive Sentinel Node in Early-Stage Breast Cancer

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Ten years of follow-up showed lymph node radiation and lymph node surgery offer similar recurrence and overall survival rates for women diagnosed with early-stage breast cancer with a positive sentinel node.

Results from the AMAROS trial were presented on Dec. 6, 2018, at the San Antonio Breast Cancer Symposium. Read the abstract of “Radiotherapy or surgery of the axilla after a positive sentinel node in breast cancer patients: 10 year follow up results of the EORTC AMAROS trial (EORTC 10981/22023).”

Treatment after a positive sentinel node

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, surgically removing other underarm lymph nodes, called axillary node dissection, was a common treatment after a positive sentinel node to reduce the risk of recurrence (the cancer coming back).

Earlier results from the AMAROS trial published in 2013 found women diagnosed with early-stage breast cancer with a positive sentinel node are less likely to have lymphedema if they get radiation to their axillary lymph nodes instead of having them surgically removed. These results also showed axillary lymph node 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.

The researchers who did the AMAROS study continued to follow the women in the study to see if having lymph node radiation or lymph node surgery affected overall survival rates. Overall survival is how long a person lives, with or without the cancer coming back.

10-year AMAROS results

In the AMAROS trial, 1,425 women diagnosed with early-stage breast cancer who had a positive sentinel node were randomly split into two treatment groups:

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

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

The two treatment groups were similar in terms of age, cancer size and grade, cancer characteristics, and whether the women received other treatments, such as hormonal therapy, after surgery.

After 10 years:

  • 1.82% (11 women) who had axillary radiation had a cancer recurrence in the axillary lymph nodes
  • 0.93% (7 women) who had axillary surgery had a cancer recurrence in the axillary lymph nodes

This difference was not statistically significant, which means it likely happened by chance, rather than because of the difference in treatment.

Metastasis-free survival — how long the women lived with no cancer coming back in a part of the body away from the breast — and overall survival rates also were similar between the two groups.

Metastasis-free survival rates were:

  • 78.2% for women treated with axillary radiation
  • 81.7% for women treated with axillary surgery

Overall survival rates were:

  • 81.4% for women treated with axillary radiation
  • 84.6% for women treated with axillary surgery

Neither of these differences was statistically significant either.

“Our new 10-year data show that axillary radiotherapy and axillary lymph node dissection provide excellent and comparable overall survival, distant-metastasis-free survival, and locoregional control,” said Mila Donker, M.D., Ph.D., radiation oncologist at the Netherlands Cancer Institute, who helped lead the study. “Given that we previously published 5-year follow-up data from the trial showing that lymphedema occurred significantly more often after axillary lymph node dissection than after axillary radiotherapy, we believe that axillary radiotherapy should be considered a good option for patients who have a positive sentinel lymph node biopsy instead of complete surgical clearance of the axillary lymph nodes.”

"Both lymph node dissection and radiotherapy to the axilla provide excellent and comparable locoregional control in sentinel node positive breast cancer patients after 10 years," said Emiel Rutgers, M.D., Ph.D., surgical oncologist at the Netherlands Cancer Institute, who presented the research. "There is significantly less lymphedema after radiotherapy after 5 years. Axillary radiation therapy can be considered standard procedure."

What does this mean for you?

To make sure that people have the appropriate lymph node surgery, the American Society for Clinical Oncology released guidelines on sentinel lymph node biopsy for people diagnosed with early-stage breast cancer. The guidelines say sentinel lymph node biopsy should be offered under these circumstances:

  • breast cancer in which there is more than one tumor, all of which have formed separately from one another (doctors call these multicentric tumors); these types of breast cancers are rare
  • ductal carcinoma in situ (DCIS) treated with mastectomy
  • women who have previously had breast cancer surgery or axillary lymph node surgery
  • women who have been treated before with chemotherapy or another systemic treatment (treatment before surgery is called neoadjuvant treatment)

Sentinel node biopsy should not be offered under these circumstances:

  • the cancer is 5 cm or larger or locally advanced (meaning the cancer has spread extensively in the breast or to the nearby lymph nodes)
  • the cancer is inflammatory breast cancer
  • the cancer is DCIS treated with lumpectomy
  • the woman is pregnant

The guidelines also say:

  • Women with negative sentinel node biopsies shouldn’t have axillary node surgery.
  • Women with one or two positive sentinel nodes who plan to have lumpectomy plus radiation also don’t need axillary node surgery.
  • Women who have one or more positive sentinel nodes and plan to have mastectomy with no radiation should be offered axillary node surgery.

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, you and your doctor will consider all the details of your situation, including your age and the characteristics of the cancer (such as size and stage) before deciding on treatments to reduce the risk of recurrence. If axillary surgery is recommended for you, it’s a good idea to ask your doctor why it’s recommended, as well as why axillary radiation isn’t a good option for you.

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

Written by: Jamie DePolo, senior editor

Reviewed by: Brian Wojciechowski, M.D., medical adviser


Lilly Oncology

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