Does Lymph Node Status Prior to Neoadjuvant Chemotherapy Influence the Number of Sentinel Nodes Removed?

New Insight for Axillary De-Escalation in Breast Cancer Surgery: "SoFT Study" Retrospective Analysis

Background: The SOUND study demonstrated that an axillary de-escalation may be sufficient in locoregional and distant disease control in selected early breast cancer (EBC) patients. To establish any preoperative variables that may drive sentinel lymph node biopsy (SLNB) omission, a study named sentinel omission risk factor (SOFT) 1.23 was planned. Methods: A single-center retrospective study from a prospectively maintained database was designed, aiming at underlying preoperative prognostic factors involved in sentinel lymph node (SLN) metastasis (lymph node involvement (LN+) vs. negative lymph node (LN-) group). Secondary outcomes included surgical room occupancy analysis for SLNB in patients fulfilling the SOUND study inclusion criteria. The institutional ethical committee Area Territoriale Lazio 2 approved the study (n° 122/23). Results: Between 1 January 2022 and 30 June 2023, 160 patients were included in the study and 26 (%) were included in the LN+ group. Multifocality, higher cT stage, and larger tumor diameter were reported in the LN+ group (p = 0.020, p = 0.014, and 0.016, respectively). Tumor biology, including estrogen and progesterone receptors, and molecular subtypes showed association with the LN+ group (p < 0.001; p = 0.001; and p = 0.001, respectively). A total of 117 (73.6%) patients were eligible for the SOUND study and the potential operating room time saved was 2696.81 min. Conclusions: De-escalating strategies may rationalize healthcare activities. Multifactorial risk stratification may further refine the selection of patients who could benefit from SLNB omission.

Nanoparticle-assisted axillary staging: an alternative approach after neoadjuvant chemotherapy in patients with pretreatment node-positive breast cancers

PURPOSE

In order to achieve an optimized method of axillary staging after neoadjuvant chemotherapy (NAC) in breast cancer patients with pretreatment positive axillary lymph nodes, we evaluated the feasibility and accuracy of nanoparticle-assisted axillary staging (NAAS) which combines carbon nanoparticles with standard sentinel lymph node biopsy (SLNB) with radioisotope and blue dye.

METHODS

Invasive breast cancer patients with pre-NAC positive axillary lymph nodes who converted to ycN0 and received surgeries from November 2020 to March 2021 were included. All patients underwent ipsilateral NAAS followed by axillary lymph node dissection. Detection rate (DR), false-negative rate (FNR), negative predictive value (NPV) and accuracy of axillary staging were calculated.

RESULTS

Eighty of 136 (58.8%) breast cancer patients converted to ycN0 after NAC and received NAAS. The DR, NPV and accuracy was 95.0%, 93.3% and 97.4% for NAAS, respectively. And the FNR was 4.2% (2/48) for NAAS, which was lower than that of standard dual-tracer SLNB (SD-SLNB) (9.5%, 4/42). Pretreatment clinical T4 classification was a risk factor for detection failure in NAAS (p = 0.016). When patients with pretreatment inflammatory breast cancers were excluded from analysis, FNR dropped to 2.2% (1/45) for NAAS.

CONCLUSION

NAAS revealed great performance in invasive breast cancer patients with pre-NAC positive axillary lymph nodes who converted to ycN0. The application of NAAS reached a better balance between more accurate axillary evaluation and less intervention. Trial registration Chictr.org.cn (ChiCTR2000039814). Registered Nov 11, 2020.

Sentinel lymph node mapping in breast cancer patients following neoadjuvant chemotherapy: systematic review and meta-analysis about head to head comparison of cN0 and cN + patients

PURPOSE

The effectiveness of sentinel lymph node (SLN) mapping and biopsy following neoadjuvant chemotherapy (NAC) in axillary lymph node staging of breast cancer (BCa) patients with initial clinical node positive status (cN +) compared to clinical node negative status (cN0) is not yet known. The aim of this meta-analysis was to compare the accuracy of SLN mapping following NAC in cN + and cN0 BCa patients.

METHODS

PubMed and Scopus were comprehensively reviewed to retrieve all the studies that performed SLN mapping/biopsy and standard axillary lymph node dissection on cN0 and cN + BCa patients following NAC. Pooled detection and false negative rates for N0 and N + patients including 95% confidence interval values (95% CI) were evaluated. Odds ratio (OR) and risk difference (RD) of SLN detection failure and false negative results were compared between two groups.

RESULTS

A total of 27 articles were included for SLN detection rate evaluation and 17 for false negative assessment. The OR and RD of detection failure in N + group compared with N0 group following NAC were 2.22 (p = 0.00, 95% CI 1.4-3.4) and 4% (p = 0.00, 95% CI 2-6%), respectively. The OR and RD of false negative rate were 1.6 (p = 0.01, 95% CI 1-2.6) and 8% (p = 0.02, 95% CI 1-14%), respectively.

CONCLUSION

SLN mapping in BCa patients following NAC shows high risk of detection failure and high false negative rate of SLN biopsy in cN + patients. In comparison with cN0 BCa patients, SLN mapping and biopsy after NAC was associated with almost two times higher odds of detection failure and false negative results in cN + patients; therefore, this method should not be recommended in this group of patients.

Sentinel Lymph Node Removal After Neoadjuvant Chemotherapy in Clinically Node-Negative Patients: When to Stop?

BACKGROUND

The maximum number of sentinel lymph nodes (SLN) to be resected to accurately stage the axilla in patients undergoing neoadjuvant chemotherapy (NAC) for the treatment of clinically node-negative (cN0) breast cancer has not been determined. We sought to determine the sequence of removal of the positive SLNs in this patient population.

METHODS

All patients aged ≥ 18 years diagnosed with cN0 invasive breast cancer who received NAC and underwent SLN surgery at Mayo Clinic Rochester between September 2008 and September 2018 were identified. Univariate analysis was performed to compare factors associated with positive nodes and where the first positive node was in the sequence of removal of the SLNs.

RESULTS

We identified 446 cancers among 440 patients with a median age of 51 (IQR: 43, 61) years. At surgery, 381 (85.4%) cancers were pathologically node (ypN) negative and 65 (14.6%) were pN + . The number of nodes removed was similar for both patients with ypN0 and ypN + disease, with a median number of SLNs removed of 2.0 (IQR: 2.0, 3.0). Of all patients with a positive node, the first positive node was most commonly the 1st node removed (75.4%), and was identified by the 3rd SLN removed in all cases.

CONCLUSIONS

Among cN0 patients treated with NAC, if a positive SLN is present, it is most commonly identified as the 1st sentinel node removed by the surgeon, and was identified by the 3rd sentinel node in our series. This suggests that once 3 SLNs have been resected, removal of additional sentinel lymph nodes does not add diagnostic value.

Selecting Node-Positive Patients for Axillary Downstaging with Neoadjuvant Chemotherapy

BACKGROUND

Axillary lymph node dissection (ALND) can be avoided in node-positive patients who receive neoadjuvant chemotherapy (NAC) if three or more negative sentinel lymph nodes (SLNs) are retrieved. We evaluate how often node-positive patients avoid ALND with NAC, and identify predictors of identification of three or more SLNs and of nodal pathological complete response (pCR).

METHODS

From November 2013 to July 2019, all patients with cT1-3, biopsy-proven N1 tumors who converted to cN0 after NAC received SLN biopsy (SLNB) with dual mapping and were identified from a prospectively maintained database.

RESULTS

630 consecutive N1 patients were eligible for axillary downstaging with NAC; 573 (91%) converted to cN0 and had SLNB, and 531 patients (93%) had three or more SLNs identified. Lymphovascular invasion (LVI; odds ratio [OR] 0.46, 95% confidence interval [CI] 0.24-0.87; p = 0.02) and increasing body mass index (BMI; OR 0.77, 95% CI 0.62-0.96 per 5-unit increase; p = 0.02) were significantly associated with failure to identify three or more SLNs. 255/573 (46%) patients achieved nodal pCR; 237 (41%) had adequate mapping. Factors associated with ALND avoidance included high grade (OR 2.51, 95% CI 1.6-3.94, p = 0.001) and receptor status (HR+/HER2- [referent]: OR 1.99, 95% CI 1.15-3.46 [p = 0.01] for HR-/HER2-, OR 3.93, 95% CI 2.40-6.44 [p < 0.001] for HR+/HER2+, and OR 8.24, 95% CI 4.16-16.3 [p < 0.001] for HR-/HER2+). LVI was associated with a lower likelihood of avoiding ALND (OR 0.28, 95% CI 0.18-0.43; p < 0.001).

CONCLUSIONS

ALND was avoided in 41% of cN1 patients after NAC. Increased BMI and LVI were associated with lower retrieval rates of three or more SLNs. ALND avoidance rates varied with receptor status, grade, and LVI. These factors help select patients most likely to avoid ALND.

Axillary Nodal Burden Assessed with Pretreatment Breast MRI Is Associated with Failed Sentinel Lymph Node Identification after Neoadjuvant Chemotherapy for Breast Cancer

Background After publication of the findings of the American College of Surgeons Oncology Group Z1071 trial, sentinel lymph node biopsy (SLNB) has been increasingly performed in patients with breast cancer after neoadjuvant chemotherapy (NAC). Purpose To investigate the pretreatment breast MRI and clinical-pathologic characteristics associated with failed sentinel node identification after NAC in patients with breast cancer. Materials and Methods Patients who underwent SLNB after NAC between January 2015 and January 2019 were retrospectively identified. Two radiologists independently reviewed the characteristics of axillary nodes (number, perinodal infiltration, cortical thickness, and maximal diameter) at pretreatment breast MRI. The associations of the clinical-pathologic and imaging characteristics of the axillary nodes with sentinel node identification were assessed by using the χ² test and/or the χ² test for trend and multivariable logistic regression with odds ratio (OR) calculation. Results A total of 276 women (mean age ± standard deviation, 48 years ± 9; range, 27-68 years) were included. Sentinel nodes were identified in 252 of the 276 patients (91%). Multivariable analysis showed that higher (stage 3 or 4) clinical T stages (OR = 5.2, P = .004 for radiologist 1; OR = 4.6, P = .01 for radiologist 2), use of a single tracer (OR = 4.3, P = .04 for radiologist 1; OR = 3.9, P = .046 for radiologist 2), a greater number (10 or more) of suspicious axillary nodes (OR = 11.5, P = .002 for radiologist 1; OR = 8.3, P = .01 for radiologist 2), and the presence of perinodal infiltration (OR = 7.0, P = .002 for radiologist 1; OR = 7.5, P = .003 for radiologist 2) were associated with failed sentinel node identification. Conclusion A greater number of suspicious axillary nodes and the presence of perinodal infiltration at pretreatment MRI, higher clinical T stages, and use of a single tracer were independently associated with failed sentinel node identification after neoadjuvant chemotherapy in patients with breast cancer. © RSNA, 2020 See also the editorial by Imbriaco in this issue.