title: Predictive Factors for Non-Sentinel Lymph Node Metastasis in the Case of Positive Sentinel Lymph Node Metastasis in Two or Fewer Nodes in Breast Cancer.
abstract: BACKGROUND
  In breast cancer, recent clinical trials have shown that sentinel lymph node biopsy (SLNB) alone without axillary lymph node dissection results in excellent prognosis if there is sentinel lymph node (SLN) metastasis in two or fewer nodes. The aim of the present study was to investigate the association between non-SLN metastasis and clinicopathological factors in case of SLN metastasis in two or fewer nodes in breast cancer.
  
  
  METHODS
  Patients who underwent SLNB for invasive breast cancer and were found to have positive SLN in two or fewer nodes were evaluated. The associations between non-SLN metastasis and clinicopahological factors were examined. Statistical analyses were performed using the Mann-Whitney and Chi-square tests, with statistical significance set at P < 0.05.
  
  
  RESULTS
  A total of 358 patients were enrolled during the study period and all of these patients were female and 54 patients had SLN metastasis (15%). Positive SLN in two or fewer nodes was identified in 44 patients (81.5%). Among these patients, 17 (38.6%) were found to have non-SLN metastasis. Non-SLN metastasis was associated with invasive tumor size (P = 0.015) and lymphatic involvement (P = 0.035). Multivariate analysis showed that tumor size (P = 0.011) and lymphatic involvement (P = 0.019) remained significant independent predictors of non-SLN metastasis, and that an invasive tumor size cut-off point of 28 mm was useful for dividing patients with positive SLN in two or fewer nodes into non-SLN-positive and non-SLN-negative groups.
  
  
  CONCLUSIONS
  Non-SLN metastasis was found in more than 30% of patients with SLN metastasis present in two or fewer nodes. Large tumor size and the presence of lymphatic involvement were significantly associated with non-SLN metastasis.
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Chie
authors.initials: C
authors.lastname: Toshikawa
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan ; Department of Nursing, Niigata University Graduate School of Health Sciences, 2-746 Asahimachi, Niigata, Niigata 951-8518, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Koyama
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Nagahashi
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Kumiko
authors.initials: K
authors.lastname: Tatsuda
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Moro
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Tsuchida
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Hasegawa
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Niwano
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Manba
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Ikarashi
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kameyama
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan ; Department of Digestive and General Surgery, Uonuma Institute of Community Medicine, Niigata University Medical and Dental Hospital, 4132 Urasa, Minami-Uonuma, Niigata 949-7302, Japan.
authors.forename: Shin-Ichi
authors.initials: S
authors.lastname: Kosugi
authors.affiliation: Division of Digestive & General Surgery, Niigata University Graduate School of Medical & Dental Sciences, 1-757 Asahimachi, Niigata, Niigata 951-8510, Japan.
authors.forename: Toshifumi
authors.initials: T
authors.lastname: Wakai
keywords: Breast cancer; Invasive tumor size; Lymphatic involvement; Metastasis; Non-sentinel lymph node; Sentinel lymph node