Fragmentation of axillary fibrofatty tissue during dissection facilitates preservation of the intercostobrachial nerve and the lateral thoracic vein

Ultrasound-assisted carbon nanoparticle suspension mapping versus dual tracer-guided sentinel lymph node biopsy in patients with early breast cancer (ultraCars): phase III randomized clinical trial

BACKGROUND

Appropriate tracing methods for sentinel lymph node biopsy (SLNB) play a key role in accurate axillary staging. This prospective, non-inferiority, phase III RCT compared the feasibility and diagnostic performance of ultrasound-assisted carbon nanoparticle suspension (CNS) mapping with dual tracer-guided SLNB in patients with early breast cancer.

METHODS

Eligible patients had primary breast cancer without nodal involvement (cN0), or had clinically positive lymph nodes (cN1) that were downstaged to cN0 after neoadjuvant chemotherapy. Patients were randomly assigned (1 : 1) to undergo either ultrasound-assisted CNS sentinel lymph node (SLN) mapping (UC group) or dual tracer-guided mapping with CNS plus indocyanine green (ICG) (GC group). The primary endpoint was the SLN identification rate.

RESULTS

Between 1 December 2019 and 30 April 2021, 330 patients were assigned randomly to the UC (163 patients) or GC (167 patients) group. The SLN identification rate was 94.5 (95 per cent c.i. 90.9 to 98.0) per cent in the UC group and 95.8 (92.7 to 98.9) per cent in the GC group. The observed difference of -1.3 (-5.9 to 3.3) per cent was lower than the prespecified non-inferiority margin of 6 per cent (Pnon-inferiority = 0.024). No significant difference was observed in metastatic node rate (30.5 versus 24.4 per cent; P = 0.222), median number of SLNs harvested (3 (range 1-7) versus 3 (1-8); P = 0.181), or duration of surgery (mean(s.d.) 7.53(2.77) versus 7.63(3.27) min; P = 0.316) between the groups. Among the subgroup of patients who had undergone neoadjuvant treatment, the SLN identification rate was 91.7 (82.2 to 100) per cent in the UC group and 90.7 (81.7 to 99.7) per cent in the GC group.

CONCLUSION

The diagnostic performance of ultrasound-assisted CNS mapping was non-inferior to that of dual tracer-guided SLN mapping with CNS plus ICG in patients with early breast cancer.

REGISTRATION NUMBER

NCT04951245 (http://www.clinicaltrials.gov).

Anatomical variations of the axilla

Purpose

The present study aimed to measure the thickness of the subcutaneous adipose tissue (SAT) at the site of the surgical incision for axillary lymph node dissection (ALND) and to record potential anatomical variations in the medial cutaneous nerve of the arm (MCNA), the intercostobrachial nerve (ICBN), the lateral thoracic vein (LTV), the lateral thoracic artery (LTA) and the pectoral muscle pedicle (PMP), considering that some details of the anatomy of these structures within the axilla are still unclear.

Methods

A prospective study was conducted in 100 consecutive patients with breast cancer who underwent ALND as part of surgical treatment. The anatomy of the dissected axilla was video recorded.

Results

The SAT thickness ranged from 8 mm to 60 mm, with an average thickness of 25.9 mm. A positive correlation was observed between the SAT thickness and the body mass index (BMI) of the evaluated patients (r = 0.68; p < 0.0001). The MCNA was the anatomical structure that was least commonly observed in the axilla (22% of cases), while the PMP was the most constant element, identified in 100% of cases. All of the studied anatomical structures observed within the axilla showed variation in at least one of the aspects analyzed, i.e., the point of entry and exit, path, number and location of divisions or branches.

Conclusion

The present study demonstrated wide variation in thickness of the SAT overlying the axilla and identified the existence of broad normative anatomical variation of the axilla.

Electronic supplementary material

The online version of this article (doi:10.1186/2193-1801-3-306) contains supplementary material, which is available to authorized users.

New anatomical classification of the axilla with implications for sentinel node biopsy

Background

The exact anatomical location of the sentinel lymph node (SLN) in the axilla has not ascertained clinically, but could be useful both for teaching purposes and to reduce the morbidity of SLN biopsy. The aim of the study was to determine the position of the SLN in the axilla and to demonstrate that this location is not random.

Methods

A consecutive series of 242 patients with stage I breast cancer (T1/T2 N0) or ductal carcinoma in situ who underwent SLN localization by peritumoral injection were included in a prospective study to map the location of the SLN in the axilla. A new anatomical classification of the lower part of the axilla based on the intersection of two anatomical landmarks, the lateral thoracic vein (LTV) and the second intercostobrachial nerve (ICBN), is described. These two constant elements form the basis of four axillary zones (A, B, C and D).

Results

In 98·2 per cent of patients the axillary SLN was located medially, alongside the LTV, either below the second ICBN (zone A, 86·8 per cent) or above it (zone B, 11·5 per cent). In only four patients (1·8 per cent) was the SLN located laterally in the axilla.

Conclusion

Regardless of the site of the tumour in the breast, 98·2 per cent of SLNs were found in the medial part of the axilla, alongside the LTV. This information should help to avoid unnecessary lateral dissections.