Factors associated with involvement of four or more axillary nodes for sentinel lymph node-positive patients.
OBJECTIVE
Sentinel lymph node-positive (SLN+) patients who are unlikely to have 4 or more involved axillary nodes might be treated with less extensive regional nodal radiation. The purpose of this study was to define possible predictors of having 4 or more involved axillary nodes.


METHODS
The records of 224 patients with breast cancer and 1 to 3 involved SLNs, who underwent completion axillary dissection without neoadjuvant chemotherapy or hormonal therapy were reviewed. Factors associated with the presence of 4 or more involved axillary nodes (SLNs plus non-SLNs) were evaluated by Pearson chi-square test of association and by simple and multiple logistic-regression analysis.


RESULTS
Of 224 patients, 42 had involvement of 4 or more axillary nodes. On univariate analysis, the presence of 4 or more involved axillary nodes was positively associated with increased tumor size, lobular histology, lymphovascular space invasion (LVSI), increased number of involved SLNs, decreased number of uninvolved SLNs, and increased size of SLN metastasis. On multivariate analysis, the presence of 4 or more involved axillary nodes was associated with LVSI, increased number of involved SLNs, increased size of SLN metastasis, and lobular histology.


CONCLUSIONS
Patients with 1 or more involved SLN, LVSI, or SLN macrometastasis should be treated to the supraclavicular fossa/axillary apex if they do not undergo completion axillary dissection. Other SLN+ patients might be adequately treated with less extensive radiation fields.
Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA 02114, USA. abkatz@partners.org
Angela
A
Katz
Andrzej
A
Niemierko
Irene
I
Gage
Sheila
S
Evans
Margaret
M
Shaffer
Frederick P
FP
Smith
Alphonse
A
Taghian
Colette
C
Magnant
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D001365:Axilla; D001943:Breast Neoplasms / Q000473:pathology* / Q000532:radiotherapy; D002278:Carcinoma in Situ / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000556:secondary*; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D015182:Lymphatic Irradiation; D008207:Lymphatic Metastasis / Q000473:pathology; D008875:Middle Aged; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy