title: Distant invasive breast cancer recurrence risk in human epidermal growth factor receptor 2-positive T1a and T1b node-negative localized breast cancer diagnosed from 2000 to 2006: a cohort from an integrated health care delivery system.
abstract: OBJECTIVE
  To determine the invasive recurrence (IR) risk among patients with small, node-negative human epidermal growth factor receptor 2 (HER2) -positive breast cancer.
  
  
  METHODS
  Among 16,975 consecutive patients with invasive breast cancer diagnosed from January 1, 2000, to December 31, 2006, in a large, integrated health care system, we identified a cohort of 234 patients with HER2-positive T1aN0M0 or T1bN0M0 (T1abN0M0) disease with a median follow-up of 5.8 years. Kaplan-Meier methods were used to estimate the percentage of patients who were free of invasive recurrence (recurrence-free interval [RFI]) at 5 years for both distant (DRFI) and local (LRFI) recurrences.
  
  
  RESULTS
  Of 15 IRs, 47% were locoregional only. Among T1ab patients not treated with adjuvant trastuzumab or chemotherapy (n = 171), the 5-year invasive DRFI was 98.2% (95% CI, 94.5% to 99.4%); it was 99.0% (95% CI, 93.0% to 99.9%) for T1a patients, and 97.0% (95% CI, 88.6% to 99.2%) for T1b patients. Locoregional plus distant 5-year invasive RFI was 97.0% (95% CI, 90.9% to 99.0%) for T1a and 91.9% (95% CI, 81.5% to 96.6%) for T1b patients; it was 89.4% (95% CI, 70.6% to 96.5%) for T1b tumors reported at 1.0 cm. T1b tumors reported at 1.0 cm accounted for 24% of the T1ab cohort, 61% of the cohort total tumor volume, and 75% of distant recurrences. Invasive RFI for T1b 1.0 cm tumors was lower than that for T1a tumors: 84.5% versus 97.4% (P = .009).
  
  
  CONCLUSIONS
  The distant IR risk of T1a HER2-positive breast cancer appears quite low. The distant IR risk in T1b patients, particularly those with 1.0-cm tumors, is higher. Potential risk differences for T1a and T1b, including the 1.0-cm tumors, should be considered when making treatment decisions.
authors.affiliation: Louis Fehrenbacher, Vallejo Medical Center, Vallejo; Angela M. Capra, Charles P. Quesenberry Jr, Regan Fulton, and Laurel A. Habel, Kaiser Permanente, Northern California, Oakland; and Parveen Shiraz, Loma Linda University, Loma Linda, CA. lou.fehrenbacher@kp.org.
authors.forename: Louis
authors.initials: L
authors.lastname: Fehrenbacher
authors.affiliation: Louis Fehrenbacher, Vallejo Medical Center, Vallejo; Angela M. Capra, Charles P. Quesenberry Jr, Regan Fulton, and Laurel A. Habel, Kaiser Permanente, Northern California, Oakland; and Parveen Shiraz, Loma Linda University, Loma Linda, CA.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Capra
authors.affiliation: Louis Fehrenbacher, Vallejo Medical Center, Vallejo; Angela M. Capra, Charles P. Quesenberry Jr, Regan Fulton, and Laurel A. Habel, Kaiser Permanente, Northern California, Oakland; and Parveen Shiraz, Loma Linda University, Loma Linda, CA.
authors.forename: Charles P
authors.initials: CP
authors.lastname: Quesenberry
authors.affiliation: Louis Fehrenbacher, Vallejo Medical Center, Vallejo; Angela M. Capra, Charles P. Quesenberry Jr, Regan Fulton, and Laurel A. Habel, Kaiser Permanente, Northern California, Oakland; and Parveen Shiraz, Loma Linda University, Loma Linda, CA.
authors.forename: Regan
authors.initials: R
authors.lastname: Fulton
authors.affiliation: Louis Fehrenbacher, Vallejo Medical Center, Vallejo; Angela M. Capra, Charles P. Quesenberry Jr, Regan Fulton, and Laurel A. Habel, Kaiser Permanente, Northern California, Oakland; and Parveen Shiraz, Loma Linda University, Loma Linda, CA.
authors.forename: Parveen
authors.initials: P
authors.lastname: Shiraz
authors.affiliation: Louis Fehrenbacher, Vallejo Medical Center, Vallejo; Angela M. Capra, Charles P. Quesenberry Jr, Regan Fulton, and Laurel A. Habel, Kaiser Permanente, Northern California, Oakland; and Parveen Shiraz, Loma Linda University, Loma Linda, CA.
authors.forename: Laurel A
authors.initials: LA
authors.lastname: Habel
mesh_terms: D000328:Adult; D000368:Aged; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000737:chemistry* / Q000188:drug therapy* / Q000453:epidemiology / Q000473:pathology; D002140:California / Q000453:epidemiology; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry / Q000188:drug therapy; D002285:Carcinoma, Intraductal, Noninfiltrating / Q000737:chemistry / Q000188:drug therapy; D015331:Cohort Studies; D019033:Delivery of Health Care, Integrated; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D058990:Molecular Targeted Therapy; D009364:Neoplasm Recurrence, Local / Q000737:chemistry* / Q000188:drug therapy* / Q000453:epidemiology / Q000473:pathology; D009367:Neoplasm Staging; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D012042:Registries; D000068878:Trastuzumab; D016896:Treatment Outcome
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D000068878:Trastuzumab; C508053:ERBB2 protein, human