Triple-negative breast cancers: unique clinical presentations and outcomes.
BACKGROUND
Triple-negative (TN) breast cancers lack estrogen receptor (ER), progesterone receptor (PR), and HER2/neu amplification (HER2). Few studies have been dedicated to characterizing this subset of cancer.


METHODS
Retrospective review of a prospectively collected database of patients treated for invasive breast cancer at a single institution. Three tumor marker groups were compared: TN [ER-/PR-/HER2-], HER2+ [ERx/PRx/HER2+], and ER+ [ER+/PRx/HER2-].


RESULTS
Over 8 years, 123 TN, 210 HER2+, and 728 ER+ patients were identified. On average, TN patients were younger (mean age TN 59.7, HER2+ 62.0, ER+ 64.5 years, P = 0.0001). They were referred for genetic testing more frequently (17% TN, 10% HER2+, 10% ER+, P = 0.055) and were most likely to have a BRCA mutation identified if tested (24% TN, 10% HER2+, 4% ER+, P = 0.019). TN tumors were larger (mean size 2.1 cm TN, 2.0 cm HER2+, 1.8 cm ER+, P = 0.031) and most commonly detected by breast exam (54% TN, 43% HER2+, 42% ER+, P = 0.025). Lymph node involvement was least common with TN tumors (21% TN, 37% HER2+, 32% ER+, P = 0.013), and angiolymphatic invasion was less common for TN than HER2+ (18% TN, 24% HER2+, 15% ER+, P = 0.006). TN patients had significantly higher local or regional recurrence (5.7% TN, 2.9% HER2+, 1.0% ER+, P = 0.001), and the worst 5-year overall survival, although this did not reach statistical significance (85% ± 6% TN, 94% ± 2% HER2+, 91% ± 2% ER+).


CONCLUSIONS
TN breast cancers are associated with unique patient presentations, tumor characteristics, and clinical outcomes of which clinicians and investigators should be aware.
Billar
Julie A Y
JA
Department of General Surgery, Mayo Clinic Arizona, Phoenix, AZ, USA.
Dueck
Amylou C
AC
Stucky
Chee-Chee H
CC
Gray
Richard J
RJ
Wasif
Nabil
N
Northfelt
Donald W
DW
McCullough
Ann E
AE
Pockaj
Barbara A
BA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D018275:Carcinoma, Lobular / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D003131:Combined Modality Therapy; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011446:Prospective Studies; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D012189:Retrospective Studies; D015996:Survival Rate; D016896:Treatment Outcome; D055815:Young Adult
D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone