For some early-stage breast cancer patients, it may be safe to forego a sentinel lymph node biopsy

For some early-stage breast cancer patients, it may be safe to forego a sentinel lymph node biopsy

Skipping sentinel lymph node biopsy (SLNB) in patients with clinically node-negative, hormone receptor (HR)-positive, HER2-negative early-stage breast cancer did not affect regional control or survival after a median follow-up of five years. This is according to the results of the phase III clinical trial BOOG 2013-08, presented at the San Antonio Breast Cancer Symposium (SABCS), December 9-12, 2025.

Over the past two decades, breast cancer treatment has shifted toward minimizing invasiveness while maintaining oncologic safety.”

Marjolein Smidt, MD, PhD, moderator of this study and professor at Maastricht University Hospital, The Netherlands

SLNB, in which a lymph node closest to the primary tumor is surgically removed and analyzed, is the preferred method for axillary staging in early breast cancer. However, increasing evidence suggests that SLNB primarily provides prognostic information and rarely changes systemic treatment decisions in patients whose lymph nodes showed no evidence of cancer, Smidt added.

“In addition to the potential scarring and discomfort associated with surgical removal of some lymph nodes, patients undergoing SLNB are also at risk of experiencing long-term side effects such as lymphedema, which is swelling caused by the accumulation of lymph fluid and often requires physical therapy,” Smidt said. The 2013-08 BOOG trial was designed to test whether omitting SLNB was safe in clinically node-negative patients undergoing breast-conserving therapy, she said.

The study involved 1,733 patients with early-stage breast cancer with tumors up to 5 cm in size whose lymph nodes were considered cancer-free based on physical examinations, preoperative ultrasounds and, where appropriate, tissue analysis experiments. All patients were treated with breast-conserving surgery and radiation between 2015 and 2022 in 25 hospitals in the Netherlands. Patients were randomly assigned to either the group that would receive SLNB therapy or the group that would forego it.

Based on data from a median five-year follow-up period of 1,574 evaluable patients - 749 in the SLNB arm and the remainder without SLNB treatment - cancer recurrence in the lymph nodes surrounding the primary tumor was observed in 0.5% of patients in the SLNB arm compared to 1.2% of patients in the SLNB arm; The difference was not statistically significant.

The median five-year regional recurrence-free survival, which was the measure of patients who showed no evidence of cancer spread to lymph nodes further from the primary tumor during their lifetime, also did not differ significantly between the two groups - 96.6% for the SLNB arm and 94.2% for the SLNB-missed arm.

“This study shows that we may be able to safely avoid sentinel lymph node biopsy, particularly in patients with HR-positive and HER-negative early-stage breast cancer, as 86.6% of tumors in this study population were of this type,” Smidt said.

Among patients with HR-positive tumors, adjuvant endocrine therapy was administered in 48.6% (SLNB arm) and 46.6% (SLNB-missed arm). “Hormonal therapy can have a major impact on a woman’s quality of life and must be carefully considered before use,” Smidt noted. "Although endocrine therapy was prescribed less frequently compared to other similar SLNB omission studies, the risk of recurrence in our study to date has still been low. However, this group requires careful follow-up due to known late recurrences," she continued.

“Not only does eliminating SLNB have a positive impact on patients, but it is also cost-effective, results in shorter patient care, and avoids complications – this can lead to better patient-reported outcomes and an overall smoother recovery,” said Smidt.

Limitations of this study include incomplete five-year follow-up for all participants and reliance on protocol analysis, as whole breast irradiation was standard practice after breast-conserving surgery at the time the study was conducted, Smidt explained. "Today's radiation therapies involve other protocols, such as partial breast irradiation. With the data from this study, we cannot prove that omitting SLNB is also safe when patients are treated with other radiation protocols, but we can try to extrapolate the results in the future."

The results apply primarily to early-stage HR-positive, HER2-negative tumors that were 2 cm or smaller; Patients with larger tumors and other breast cancer subtypes were underrepresented in the study, said Smidt.

The study was funded by the Dutch Cancer Society, the Central Health Insurance and the Netherlands Organization for Health Research and Development. Smidt reports receiving funding from Roche, Nutricia, and Servier Pharma, as well as material from Illumina.

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