Najim O, et al. - In clinically node-negative axilla (cN0) breast cancer, the negative predictive value (NPV) of sentinel node (SN) after neo-adjuvant chemotherapy (NACT) was assessed. Researchers also determined if axillary lymph node dissection (ALND) can be avoided after NACT irrespective of the pre-treatment clinical staging of the axilla, in case of a normalization of the 18F-fluoro-2-deoxy-glucose positron emission tomography scan (PET-CT scan). As per findings, they recommend performing SNB as a standard procedure after NACT in case of a cN0. ALND should not be performed if the SN is negative and normalization of PET CT after NACT was noted

Methods

• Researchers performed a single institution prospective study from March 29, 2010 until December 1, 2015 at the Multidisciplinary Breast Clinic of the Antwerp University Hospital.
• For study participation, inclusion criteria were breast cancer, age above 18 years, female, and tumor stages T2-T4 N0-3 or T1N1-N3.
• Staging of all patients was performed by a mammography, ultrasound of the axilla, MRI of the breast, PET-CT scan and bone scintigraphy.
• NACT consisting of 12 cycles of paclitaxel or 4 cycles of docetaxel followed by dose dense doxorubicin or epirubicin/cyclofosfamide or vice versa as a standard initial treatment was administered.
• For early tumor response evaluation, a PET-CT scan was performed after 6 weeks.
• To identify the SN on the day of operation, they used a ⁹⁹mTC-labelled nanocolloid.
• They removed the SN separately together with a complete ALND during the surgery.

Results

• Researchers enrolled 150 patients in this study; 129 of these were eligible for analysis.
• They identified 53 patients with a positive SN; of these, 32 have a positive axillary lymph nodes (ALN) with a positive predictive value (PPV) of 60%
• A negative SN was observed in 76 patients; of these, 6 had a positive ALN (NPV 92%).
• With a false omission rate (FOR) of 8%, the sensitivity of 84% and the specificity of 76% were noted.
• Observations revealed that in a total of 45 patients, ALN were clinical negative and no suspect lymph nodes were seen on ultrasound, MRI and PET-CT scan; 45 patients had negative a SN, with no ALN and two patients had a positive SN of which one had axillary involvement (NPV 100%).
• The FOR of cN1: 5%, cN2: 37%, cN3 33%.
• Out of 84 patients, a total of 22 patients (26%) of which 15/49 cN1 (30%), 6/23 (26%) cN2, 1/12 (8%) have after 6 weeks of chemotherapy and normalization on PET-CT scan.
• A negative SN and ALN were observed in a total of 17 patients.
• In this group, the FOR was 0%.