Two new studies have found that some HER2-positive breast cancer patients can avoid sentinel lymph node biopsy (SLNB) after neoadjuvant systemic therapy.
SLNB is commonly used following neoadjuvant therapy, but evidence has suggested that many women may not have any residual disease in the lymph nodes at this point. The two new studies examining the need for SLNB were presented at the 11th European Breast Cancer Conference, held March 21–23 in Barcelona.
In one study, researchers included 90 patients with either HER2-positive or triple-negative breast cancer who underwent neoadjuvant treatment; of those, 54 patients (60%) were cN0, and 36 (40%) were cN1.
In the cN0 patients, 42.5% had a breast pathologic complete response (pCR), and 96.3% had no evidence of axillary node metastases following neoadjuvant therapy. Two patients (3.7%) had residual axillary disease, neither of whom achieved a pCR. Among the cN1 patients, 76.5% of those with a pCR and 36.8% of those without a pCR had no residual nodal disease (P = .02).
“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 Christian Sisó, MD, of the University Hospital Vall Hebron in Barcelona, according to a press release. “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.”
The second study included 298 patients, only with cN0 disease, treated again with neoadjuvant systemic therapy. Four of 54 patients with HER2-positive/hormone receptor (HR)-positive disease had a positive sentinel lymph node after treatment; none of the 39 patients with HER2-positive/HR-negative disease had positive nodes, and 1 of 66 patients with triple-negative disease had positive nodes. In contrast, 35 of the 139 patients with HER2-negative/HR-positive disease had positive sentinel lymph nodes.
“These results suggest that SLNBs 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 Marieke van der Noordaa, MD, of the Netherlands Cancer Institute in Amsterdam. “This could mean the side effects of SLNBs could be prevented in these women.”
Van der Noordaa and others are starting a new trial for patients with HER2-positive or triple-negative breast cancer to further examine whether avoiding these biopsies is possible.