Skipping Axillary Lymph Node Dissection in Breast Cancer?

TOPLINE:

Skipping standard axillary lymph node dissection led to very low rates of axillary recurrence in patients with node-positive breast cancer who became node-negative following neoadjuvant chemotherapy, and these rates did not differ significantly between patients who underwent sentinel lymph node biopsy or targeted axillary dissection, new research suggests.

METHODOLOGY:

  • There are limited data on outcomes among patients with breast cancer who skip standard axillary lymph node dissection after being downstaged from node-positive to node-negative disease following neoadjuvant chemotherapy.
  • In the current analysis, researchers aimed to clarify the rate of axillary recurrence after omitting axillary lymph node dissection in this patient population and to determine whether the rate of axillary recurrence differed among patients undergoing less invasive approaches — sentinel lymph node biopsy or targeted axillary dissection.
  • To investigate, researchers looked back at 1144 patients with stages II-III biopsy-proven node-positive breast cancer treated with neoadjuvant chemotherapy across 25 centers in 11 countries; 93% of patients had N1 disease, 54% had ERBB2 (formerly HER2)–positive illness, and 66% had a breast pathologic complete response.
  • Overall, 666 patients (58%) underwent sentinel lymph node biopsy with dual tracer mapping, and 478 (42%) underwent targeted axillary dissection. Targeted axillary dissection included sentinel lymph node biopsy with single or dual mapping alongside imaging-guided localization of the positive-clipped lymph node. 
  • The primary endpoints were 3- and 5-year rates of any axillary recurrence. Secondary endpoints included locoregional recurrence, any invasive (locoregional and distant) recurrence, and number of lymph nodes removed.

TAKEAWAY:

  • Patients who underwent targeted axillary dissection were more likely to receive nodal radiation therapy (85% vs 78%). The clipped node was successfully retrieved in 97% of targeted axillary dissection cases and 86% of sentinel lymph node biopsy cases (without localization).
  • The mean number of sentinel lymph nodes retrieved was lower with targeted axillary dissection vs sentinel lymph node biopsy (3 vs 4; P < .001), and the mean number of total lymph nodes removed was also lower with targeted axillary dissection (3.95 vs 4.44 with sentinel lymph node biopsy; P < .001).
  • The 3- and 5-year rates of any axillary recurrence were 0.65% and 1.0%, respectively. At 3 years, there was no significant difference in axillary recurrence rates between targeted axillary dissection (0.5%) and sentinel lymph node biopsy (0.8%).
  • At 5 years, the rate of locoregional recurrence was 2.7%, and the rate of any invasive recurrence was 10%, with no difference by surgical group.

IN PRACTICE:

This cohort study suggests that early axillary recurrence after omitting of axillary lymph node dissection in patients whose cancer converted to node-negative disease “is a very rare event” and was not significantly lower after targeted axillary dissection vs sentinel lymph node biopsy, the authors concluded. “Although longer follow-up is needed, these results support omission of [axillary lymph node dissection] in patients with nodal pathologic complete response after [neoadjuvant chemotherapy],” the authors said.

SOURCE:

The study, with first author Giacomo Montagna, MD, MPH, with Memorial Sloan Kettering Cancer Center, New York City, was published online on April 25 in JAMA Oncology.

LIMITATIONS:

The study was retrospective, and there were differences in median follow-up time between groups. Adjusting for baseline and treatment differences between groups was not possible, given the low number of axillary recurrences and the random effect caused by the treatment site. The study may have been underpowered to detect small outcome differences between groups.

DISCLOSURES:

The study was funded in part by a grant from the National Cancer Institute to Memorial Sloan Kettering Cancer Center. Several authors reported financial ties to pharmaceutical companies.

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