title: Predictive factors of non-sentinel lymph node involvement in patients with invasive breast cancer and sentinel node micrometastases.
abstract: Patient-related, tumor-related, and sentinel node (SN)-related factors have been identified with the aim of predicting non-SN status in patients with SN micrometastases. According to our previous experience, primary tumor size (p=0.005) and the presence of lymphovascular invasion (LVI) (p=0.000) significantly predicted non-SN status in patients with SN micrometastasis; moreover, non-SN metastases were never detected in patients with pT1a-1b, G1, and no LVI. A prospective assessment was undertaken in a validation set of 126 patients to confirm these findings. Univariate analysis indicated that primary tumor size (p=0.05), Scarff-Bloom-Richardson (SBR) grade (p=0.008), LVI (p=0.001), and the number of mitoses/mm(2) (p=0.01) were significant predictors of non-SN status. By logistic regression analysis, tumor size (p=0.03), LVI (p=0.001), grade (p=0.003) and the number of mitoses/mm(2) (p=0.01) were the only variables remaining in the model. Three subsets of patients were identified: i) 18.3% of patients (pT1, G1, and no LVI) had tumor-negative non-SN (no risk group); ii) 37.3% of patients (number of mitoses/mm(2) <10, SBR grade II-III) had a rate of tumor-positive non-SN <15% (intermediate risk); iii) 44.4% of patients had a mean rate of non-SN involvement of 46% (high risk). By these parameters, more than 50% of patients could be selectively spared unnecessary axillary lymph node dissection without staging or therapeutic benefit, especially in patients with well-differentiated pT1 tumors without LVI.
authors.affiliation: Semeiotica Chirurgica e Chirurgia Senologica, IRCCS "San Martino-IST" Genova, L.go R. Benzi, 10, 16132, Genoa, Italy. marco.gipponi@hsanmartino.it.
authors.forename: Daniele
authors.initials: D
authors.lastname: Friedman
authors.forename: Marco
authors.initials: M
authors.lastname: Gipponi
authors.forename: Federica
authors.initials: F
authors.lastname: Murelli
authors.forename: Paolo
authors.initials: P
authors.lastname: Meszaros
authors.forename: Nicola
authors.initials: N
authors.lastname: Solari
authors.forename: Michela
authors.initials: M
authors.lastname: Massa
authors.forename: Francesca
authors.initials: F
authors.lastname: Depaoli
authors.forename: Paola
authors.initials: P
authors.lastname: Baccini
authors.forename: Franca
authors.initials: F
authors.lastname: Carli
authors.forename: Maurizio
authors.initials: M
authors.lastname: Gallo
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Cafiero
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000556:secondary*; D018275:Carcinoma, Lobular / Q000556:secondary*; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D061206:Neoplasm Micrometastasis; D047368:Tumor Burden
keywords: Sentinel lymph node; breast cancer staging; micrometastases