Size of Extranodal Extension on Sentinel Lymph Node Dissection in the American College of Surgeons Oncology Group Z0011 Trial Era.
OBJECTIVE
Based on the American College of Surgeons Oncology Group Z0011 trial exclusion criteria, patients with T1N0 or T2N0 breast cancer with 1 or 2 positive sentinel lymph nodes (SLNs) are recommended to undergo axillary lymph node dissection if extranodal extension (ENE) is present.


OBJECTIVE
To determine the effect of ENE size on residual axillary nodal burden, disease recurrence, and survival in patients meeting Z0011 criteria.


METHODS
Retrospective cohort study between January 1, 2000, and December 31, 2012, at a single tertiary cancer center. Patients had T1 or T2 breast cancer with 1 or 2 positive SLNs. The ENE was classified as 2 mm or smaller or as larger than 2 mm.


METHODS
Nodal burden, disease recurrence, and overall survival.


RESULTS
Of 208 patients, 149 (71.6%) had no ENE, 21 (10.1%) had ENE 2 mm or smaller, and 38 (18.3%) had ENE larger than 2 mm on SLN dissection. The median follow-up time was 60 months (range, 1-158 months). The mean (SD) total number of positive lymph nodes differed significantly for the group with no ENE (1.72 [1.39]) vs the group with ENE 2 mm or smaller (3.22 [2.09]; P < .001) and vs the group with ENE larger than 2 mm (4.26 [5.01]; P < .001). Similar patterns were observed for mean (SD) nonsentinel lymph node metastases: 0.48 (1.30) for no ENE vs 1.91 (2.07) with ENE 2 mm or smaller (P = .02) and vs 2.95 (4.95) with ENE larger than 2 mm (P < .001). For the group without ENE vs the group with ENE 2 mm or smaller, there were no significant differences in recurrence (distant recurrence, 4 patients [2.7%] vs 1 patient [4.8%], respectively; P = .62) or in mortality (18 patients [12.1%] vs 4 patients [19.1%], respectively; P = .48). For the group without ENE vs the group with ENE larger than 2 mm, there were no significant differences in recurrence (distant recurrence, 4 patients [2.7%] vs 4 patients [10.5%], respectively; P = .19) or in mortality (18 patients [12.1%] vs 9 patients [23.7%], respectively; P = .07).


CONCLUSIONS
Presence of ENE on SLN dissection is associated with N2 disease. Despite increased nodal burden, patients with 1 or 2 positive SLNs and ENE 2 mm or smaller demonstrated recurrence and survival rates similar to those of patients without ENE. Reporting of ENE size should be standardized and required.
Department of Surgery, Loma Linda University School of Medicine, Loma Linda, California.
Audrey H
AH
Choi
Department of Pathology and Human Anatomy, Loma Linda University School of Medicine, Loma Linda, California.
Summer
S
Blount
Department of Pathology and Human Anatomy, Loma Linda University School of Medicine, Loma Linda, California.
Mia N
MN
Perez
Department of Surgery, Loma Linda University School of Medicine, Loma Linda, California.
Carlos E
CE
Chavez de Paz
Department of Surgery, Loma Linda University School of Medicine, Loma Linda, California.
Samuel A
SA
Rodriguez
Department of Surgery, Loma Linda University School of Medicine, Loma Linda, California.
Matthew
M
Surrusco
Department of Surgery, Loma Linda University School of Medicine, Loma Linda, California.
Carlos A
CA
Garberoglio
Department of Surgery, Loma Linda University School of Medicine, Loma Linda, California.
Sharon S
SS
Lum
Department of Surgery, Loma Linda University School of Medicine, Loma Linda, California.
Maheswari
M
Senthil
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001365:Axilla; D001943:Breast Neoplasms / Q000175:diagnosis / Q000556:secondary* / Q000601:surgery; D002140:California / Q000453:epidemiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008197:Lymph Node Excision / Q000379:methods*; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D015412:Mastectomy, Segmental; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D009367:Neoplasm Staging; D011379:Prognosis; D012189:Retrospective Studies; D021701:Sentinel Lymph Node Biopsy / Q000379:methods*; D015996:Survival Rate / Q000639:trends; D013997:Time Factors