Applicability of magnetic seeds for target lymph node biopsy after neoadjuvant chemotherapy in initially node-positive breast cancer patients: data from the AXSANA study.

PURPOSE: Currently, various techniques are available to mark and selectively remove initially suspicious axillary lymph nodes (target lymph nodes, TLNs) in breast cancer patients receiving neoadjuvant chemotherapy (NACT). To date, limited data are available on whether the use of magnetic seeds (MS) is suitable for localizing TLNs. This study aimed to investigate the feasibility of MS in patients undergoing target lymph node biopsy (TLNB) or targeted axillary dissection (TAD) after NACT. METHODS: Prospective data from the ongoing multicentric AXSANA study were extracted from selected patients in whom the TLN had been marked with an MS before NACT and who were enrolled from June 2020 to June 2023. The endpoints of the analysis were the detection rate, the rate of lost markers, and the potential impairment on magnetic resonance imaging (MRI) assessment. RESULTS: In 187 patients from 27 study sites in seven countries, MS were placed into the TLN before NACT. In 151 of these, post-NACT surgery had been completed at the time of analysis. In 146 patients (96.0%), a TLN could successfully be detected. In three patients, the seed was removed but no lymphoid tissue was detected on histopathology. The rate of lost markers was 1.2% (2 out of 164 MS). In 15 out of 151 patients (9.9%), MRI assessment was reported to be compromised by MS placement. CONCLUSION: MS show excellent applicability for TLNB/TAD when inserted before NACT with a high DR and a low rate of lost markers. Axillary MS can impair MRI assessment of the breast. TRIAL REGISTRATION NUMBER: NCT04373655 (date of registration May 4, 2020).

Swedish prospective multicenter trial on the accuracy and clinical relevance of sentinel lymph node biopsy before neoadjuvant systemic therapy in breast cancer.

PURPOSE: The timing of sentinel lymph node biopsy (SLNB) in the context of neoadjuvant systemic therapy (NAST) in breast cancer is still controversial. SLNB before NAST has been evaluated in few single-institution studies in which axillary lymph node dissection (ALND), however, was commonly not performed in case of a negative SLNB. We investigated the potential clinical relevance of SLNB before NAST by performing ALND in all patients after NAST. METHODS: This national multicenter trial prospectively enrolled clinically node-negative breast cancer patients planned for NAST at 13 recruiting Swedish hospitals between October 2010 and December 2015. SLNB before NAST was followed by ALND after NAST in all individuals. Repeat SLNB after NAST was encouraged but not mandatory. RESULTS: SLNB before NAST was performed in 224 patients. The identification rate was 100% (224/224). The proportion of patients with a negative SLNB before NAST but positive axillary lymph nodes after NAST was 7.4% (nine of 121 patients, 95% CI 4.0-13.5). Among those with a positive SLNB before NAST, 23.2% (86/112) had further positive lymph nodes after NAST. CONCLUSIONS: In clinically node-negative patients, SLNB before NAST is highly reliable. With this sequence, ALND and regional radiotherapy can be safely omitted in patients with a negative SLNB provided good clinical response to NAST. Additionally, SLNB-positive patients upfront will receive correct nodal staging unaffected by NAST and be consequently offered adjuvant locoregional treatment according to current guidelines pending the results of ongoing randomized trials.

Swedish prospective multicenter trial evaluating sentinel lymph node biopsy after neoadjuvant systemic therapy in clinically node-positive breast cancer.

PURPOSE: Patients with clinically node-positive breast cancer planned for neoadjuvant systemic therapy (NAST) may draw advantages from the nodal downstaging effect and reduce the extent of axillary surgery with sentinel lymph node biopsy (SLNB) performed after NAST. Since there are concerns about lower sentinel lymph node (SLN) detection and higher false-negative rates (FNR) in this setting, our aim was to define the accuracy of SLNB after NAST. METHODS: This Swedish national multicenter trial prospectively recruited 195 breast cancer patients from ten hospitals with T1-T4d biopsy-proven node-positive disease planned for NAST between October 1, 2010 and December 31, 2015. Clinically node-negative axillary status after NAST was not mandatory. SLNB was always attempted and followed by a completion axillary lymph node dissection (ALND). RESULTS: The SLN identification rate was 77.9% (152/195) but improved to 80.7% (138/171) with dual mapping. The median number of SLNs was two (range 1-5). A positive SLNB was found in 52% (79/152), almost 66% (52/79) of whom had additional positive non-sentinel lymph nodes. The overall pathologic nodal response rate was 33.3% (66/195). The overall FNR was 14.1% (13/92) but decreased to 4% (2/50) when only patients with two or more sentinel nodes were analyzed. CONCLUSIONS: In biopsy-proven node-positive breast cancer, SLNB after NAST is feasible even though the identification rate is lower than in clinically node-negative patients. Since the overall FNR is unacceptably high, the omission of ALND should only be considered if two or more SLNs are identified.

Impact of previous surgery on sentinel lymph node mapping: Hybrid SPECT/CT before and after a unilateral diagnostic breast excision.

BACKGROUND: Earlier studies have shown conflicting results regarding the accuracy of sentinel lymph node biopsy after previous breast surgery, especially after a surgical biopsy. PURPOSE: To compare lymph drainage patterns before and after a diagnostic unilateral surgical biopsy using the exact anatomical localisation of sentinel lymph nodes defined by SPECT/CT. MATERIAL AND METHODS: Thirty-seven women planned for unilateral surgical excision of an unsuspicious breast lesion were prospectively examined between September 2011 and January 2015. Hybrid SPECT/CT lymphoscintigraphy of the thorax and neck region with bilateral subareolar injections of 99mTc-Nanocoll was performed one week before and six weeks after surgery. The non-operated side served as a control. The primary outcome measure was the concordance between pre- and postoperative number and localisation of sentinel lymph nodes. RESULTS: Sentinel lymph node detection rate with SPECT/CT on operated sides was 91.9 per cent (34 of 37 procedures), to be compared with a detection rate of 93.7 per cent on all non-operated sides (104 of 111 procedures, P = 0.771). Partial or total concordance regarding the localisation and number of sentinel lymph nodes was 85.7 per cent (30 out of 35) on operated and 88.9 per cent (32 out of 36 patients) on non-operated breast sides (P = 0.735). CONCLUSION: Breast surgery slightly decreased the concordance between pre- and postoperative sentinel lymph nodes, but this finding was not statistically significant. Our results thus support that it is feasible to perform a sentinel lymph node biopsy after previous breast excisional surgery with an acceptable level of safety.