Lymph Node Surgery Unnecessary for Patients with Certain Breast Cancer Subtypes

New findings presented at the 11^th European Breast Cancer Conference suggest that sentinel lymph node biopsies may be avoidable among patients with triple-negative or HER2-positive breast cancer.

Once breast cancer has metastasized, patients have few treatment options. To detect metastasis, patients typically undergo sentinel lymph node dissection, which is one of the first places the disease spreads.

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Although dissection can help physicians formulate a stronger attack against breast cancer, patients can experience long-term swelling, numbness, and reduced movement of the arm, according to the authors.

The results of 2 recent studies suggest that patients diagnosed with triple-negative or HER2-positive breast cancer who respond to chemotherapy prior to surgery may be able to avoid biopsies due to a low risk of having cancer cells in the sentinel lymph nodes, according to the session.

Included in the first study were 90 patients treated at the University Hospital Vall Hebron between January 2011 and December 2016. All patients had triple-negative or HER2-positive breast cancer and were administered chemotherapy prior to surgery.

The patients also underwent ultrasound scans to check whether the disease spread to the lymph nodes, which was then confirmed with pathology tests.

The authors noted that 60% of patients had no signs of cancer in their lymph nodes prior to treatment and 96.3% had no cancer in their lymph nodes post-treatment.

"Our results suggest that giving chemotherapy to patients with these types of breast cancer before considering surgery offers the possibility of reducing or even avoiding surgery,” said author of the first study Christian Sisó, MD. “By giving drug treatment first we are able to see how well the drugs work against an individual tumor. If they are working well, they can clear cancer cells from the lymph nodes and in the breast.”

Another 42.5% of patients had no cancer cells in the affected breast and none had cancer cells in their lymph nodes.

Of the 40% of patients who had cancer cells in their lymph nodes prior to treatment, 14.2% had no signs of cancer in the breast after treatment and 76.5% were free of cancer cells in their lymph nodes, according to the study.

"In women who had no signs of cancer in their lymph nodes and where treatment seems to have cleared the cancer in the breast, lymph node surgery might be avoided,” Dr Sisó said. “On the other hand, in women who had signs of cancer in their lymph nodes before treatment, there is still a risk that the disease will remain there, even when it has been successfully treated in the breast itself."

Included in the second study were 294 patients with breast cancer treated at the Netherlands Cancer Institute between January 2013 and September 2017. Testing with ultrasound, PET/CT, or cytology indicated that no patients had signs of cancer cells in their lymph nodes. All of the patients were administered chemotherapy.

After chemotherapy, no patients with HER2-positive breast cancer had cancerous cells in their sentinel lymph nodes. Only 1% of patients with triple-negative disease had cancer cells in their lymph nodes, according to the study.

The authors also found that 2% of patients with a poor grade tumor had cancer cells in their lymph nodes and all patients whose tumors responded to chemotherapy had no signs of cancer in their lymph nodes.

"These results suggest that sentinel lymph node biopsies are most likely not needed in many women who undergo upfront chemotherapy and who have no sign of cancer in their lymph nodes before the start of chemotherapy,” said author of the second study Marieke van der Noordaa, MD. “This could mean the side effects sentinel lymph node biopsies could be prevented in these women."