Prognostic significance of further axillary dissection in breast cancer patients with micrometastases & the number of micrometastases: a SEER population-based analysis

Efficacy and safety comparison between axillary lymph node dissection with no axillary surgery in patients with sentinel node-positive breast cancer: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis aimed to study the evidence on the efficacy and safety of omitting axillary lymph node dissection (ALND) for patients with clinically node-negative but sentinel lymph node (SLN)-positive breast cancer using all the available evidence.

METHODS

The Embase, Medline, and Cochrane Library databases were searched through February 25, 2023. Original trials that compared only the sentinel lymph node biopsy (SLNB) with ALND as the control group for patients with clinically node-negative but SLN-positive breast cancer were included. The primary outcomes were axillary recurrence rate, total recurrence rate, disease-free survival (DFS), and overall survival (OS). Meta-analyses were performed to compare the odds ratio (OR) in rates and the hazard ratios (HR) in time-to-event outcomes between both interventions. Based on different study designs, tools in the revised Cochrane risk of bias tool were used for randomized trials and the risk of bias in nonrandomized studies of interventions to assess the risk of bias for each included article. Funnel plots and Egger's test were used for the publication's bias assessment.

RESULTS

In total, 30 reports from 26 studies were included in the systematic review (9 reports of RCTs, 21 reports of retrospective cohort studies). According to our analysis, omitting ALND in patients with clinically node-negative but SLN-positive breast cancer had a similar axillary recurrence rate (OR = 0.95, 95% confidence interval (CI): 0.76-1.20), DFS (HR = 1.02, 95% CI: 0.89-1.16), and OS (HR = 0.97, 95% CI: 0.92-1.03), but caused a significantly lower incidence of adverse events and benefited in locoregional recurrence rate (OR = 0.76, 95% CI: 0.59-0.97) compared with ALND.

CONCLUSION

For patients with clinically node-negative but SLN-positive breast cancer (no matter the number of the positive SLN), this review showed that SLNB alone had a similar axillary recurrence rate, DFS, and OS, but caused a significantly lower incidence of adverse events and showed a benefit for the locoregional recurrence compared with ALND. An OS benefit was found in the Macro subset that used SLNB alone versus complete ALND. Therefore, omitting ALND is feasible in this setting.

TRIAL REGISTRATION

CRD 42023397963.

The prognostic significance of further axillary dissection for sentinel lymph node micrometastases in female breast cancer: A competing risk analysis using the SEER database

BACKGROUND

Sentinel lymph node (SLN) biopsy has been widely recognized as an excellent surgical and staging procedure for early-stage breast cancer, and its development has greatly improved the detection of micrometastases. However, the axillary treatment of micrometastasis has been the subject of much debate.

METHODS

We identified 427,131 women diagnosed with breast cancer from 2010 to 2018 in the Surveillance, Epidemiology, and End Results (SEER) database. Patients whose nodal status was micrometastases (pTxN1miM0) were classified into two groups: the SLNB only group and SLNB with complete ALND group, and we used these classifications to carry out propensity-score matching (PSM) analysis. The primary and secondary endpoints were OS and BCSS, respectively. We then implemented the Kaplan-Meier method and Cox proportional hazard model and used Fine and Gray competitive risk regression to identify factors associated with the risk of all-cause mortality.

RESULTS

After the PSM, 1,833 pairs were included in total. The SLNB with complete ALND showed no significant difference in OS (HR=1.04, 95% CI: 0.84-1.28, P=0.73) or BCSS (HR= 1.03, 95% CI: 0.79-1.35, P=0.82) compared to the SLNB only group, and axillary treatment was not associated with breast cancer-specific death (BCSD) (HR=1.13, 95% CI: 0.86-1.48, P=0.400) or other cause-specific death (OCSD) (HR=0.98, 95% CI:0.70-1.38, P=0.920). There was no statistically significant difference in the cumulative incidence of BCSD (Grey's test, P=0.819) or OCSD (Grey's test, P=0.788) for between the two groups either. For different molecular subtypes, patients in the SLNB only group showed no statistically significant differences from those in the SLNB with complete ALND group with Luminal A (HR=1.00, 95% CI:0.76-1.32, P=0.98) or Luminal B (HR=0.82, 95% CI:0.42-1.62, P=0.55) but similar OS to HER2-enriched (HR=1.58, 95% CI:0.81-3.07, P=0.19) or triple negative breast cancers (HR=1.18, 95% CI:0.76-1.81, P=0.46).

CONCLUSIONS

Our results suggest that in early breast cancer patients with micrometastasis, complete ALND does not seem to be required and that SLNB suffices to control locoregional and distant disease, with no significant adverse effects on survival compared to complete ALND.

Omitting completion axillary lymph node dissection after detection of sentinel node micrometastases in breast cancer: first results from the prospective SENOMIC trial

BACKGROUND

Completion axillary lymph node dissection has been abandoned widely among patients with breast cancer and sentinel lymph node micrometastases, based on evidence from prospective RCTs. Inclusion in these trials has been subject to selection bias, with patients undergoing mastectomy being under-represented. The aim of the SENOMIC (omission of axillary lymph node dissection in SENtinel NOde MICrometases) trial was to confirm the safety of omission of axillary lymph node dissection in patients with breast cancer and sentinel lymph node micrometastases, and including patients undergoing mastectomy.

METHODS

The prospective SENOMIC multicentre cohort trial enrolled patients with breast cancer and sentinel lymph node micrometastases who had breast-conserving surgery or mastectomy at one of 23 Swedish hospitals between October 2013 and March 2017. No completion axillary lymph node dissection was performed. The primary endpoint was event-free survival, with a trial accrual target of 452 patients. Survival proportions were based on Kaplan-Meier survival estimates.

RESULTS

The trial included 566 patients. Median follow-up was 38 (range 7-67) months. The 3-year event-free survival rate was 96.2 per cent, based on 26 reported breast cancer recurrences, including five isolated axillary recurrences. The unadjusted 3-year event-free survival rate was higher than anticipated, but differed between patients who had mastectomy and those who underwent breast-conserving surgery (93.8 versus 97.8 per cent respectively; P = 0.011). Patients who underwent mastectomy had significantly worse tumour characteristics. On univariable Cox proportional hazards regression analysis, patients who had mastectomy without adjuvant radiotherapy had a significantly higher risk of recurrence than those who underwent breast-conserving surgery (hazard ratio 2.91, 95 per cent c.i. 1.25 to 6.75).

CONCLUSION

After 3 years, event-free survival was excellent in patients with breast cancer and sentinel node micrometastases despite omission of axillary lymph node dissection. Long-term follow-up and continued enrolment of patients having mastectomy, especially those not receiving adjuvant radiotherapy, are of utmost importance.