Clinical significance of HER2-positive and triple-negative status in small (≤ 1 cm) node-negative breast cancer.
BACKGROUND
Data regarding the clinical significance of HER2(+) and TN status in patients with small node-negative tumors are limited and conflicting. It remains unclear who, among those with small lesions, might benefit from more aggressive adjuvant therapy.


METHODS
We identified all node-negative breast cancer patients with tumor size ≤ 1 cm diagnosed between January 1, 1995 and December 31, 2008 using our institutional breast service database. Patients were classified according to their receptor status into 3 groups: (1) hormone receptor (HR)-positive (estrogen receptor [ER]- or progesterone receptor [PR]-positive, HER2(-)); (2) HER2(+) (immunohistochemistry 3(+) or fluorescence in situ hybridization amplification ≥ 2); and (3) TN (ER(-), PR(-), and HER2(-)). RFS was calculated using Kaplan-Meier methods.


RESULTS
Among 656 patients with tumors ≤ 1 cm, 494 (75%) of the patients were HR(+), 107 (16%) were HER2(+), and 55 (9%) were TN. Median age was 59 years (range, 27-92 years). Median follow-up was 3.5 years. The 5-year RFS rates were 98.2%, 97.1%, and 83.5% in patients with HR(+), HER2(+), and TN tumors, respectively (P < .001). In multivariate analysis, TN status was associated with worse RFS (hazard ratio, 6.70; 95% confidence interval [CI], 3.02-14.86), and HER2(+) was not (hazard ratio, 1.64; 95% CI, 0.73-3.69).


CONCLUSIONS
TN, but not HER2(+) status, was associated with worse RFS in patients with T1abN0 tumors, and adjuvant chemotherapy might be considered in patients with TN breast cancer.
Beth Israel Medical Center, Mount Sinai Health System, New York, NY.
Elan
E
Gorshein
Beth Israel Medical Center, Mount Sinai Health System, New York, NY.
Paula
P
Klein
Beth Israel Medical Center, Mount Sinai Health System, New York, NY.
Susan K
SK
Boolbol
Beth Israel Medical Center, Mount Sinai Health System, New York, NY. Electronic address: tshao@chpnet.org.
Theresa
T
Shao
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D016016:Proportional Hazards Models; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis* / Q000235:genetics; D012307:Risk Factors; D064726:Triple Negative Breast Neoplasms / Q000235:genetics* / Q000401:mortality* / Q000473:pathology*
D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases
HER2+ breast cancer; Hormone receptor; Small breast cancer; T1abN0; Triple-negative breast cancer