title: Endocrine sensitivity is decisive for patient outcome in small node-negative breast cancers (BC) (pT1a,b) - results from the Munich Cancer Registry.
abstract: OBJECTIVE
  In clinical routine, adjuvant systemic therapy in small node-negative (N0) BC is controversial, in particular in HER2-positive disease. We aimed to evaluate outcome of consecutive patients with small N0 BC in a population-based cancer registry and thus consequently substantiate indications for chemotherapy in those patient subgroups at increased relapse risk or poor survival.
  
  
  METHODS
  From 2002 to 2009 (median follow-up 6 years), 9707 primary breast cancer patients with N0 tumors <2 cm (pTis, pT1N0M0) were reported to the Munich Cancer Registry. Patients with pTis tumors (n = 1870) served as internal comparator. Time to progression, observed (OS) and relative survival rates (Kaplan-Meier estimates) are presented. Cox regression analysis was used to assess the influence of tumor size, age, HR-, and HER2-status.
  
  
  RESULTS
  10-year-OS for pTis was 94.0%. In HR-positive tumors it was 91.9% in pT1a, 90.6% in pT1b, and 86.8% in pT1c. In HR-negative tumors, rates were 91.7%, 86.8%, and 86.8%, respectively. In HER2-positive tumors it was 81.2%, 88.1%, and 86.7%, in HER2-negative 93.1%, 90.6%, and 86.0%, respectively. In the multivariate model, age, tumor size, and HR-status showed a significant impact on OS (HRneg. vs. HRpos.: hazard ratio 1.50 (95% CI; 1.12-1.99), while HER2-status was not an independent prognostic factor.
  
  
  CONCLUSIONS
  Prognosis of N0 tumors <1 cm is excellent, especially if they are HR-positive, even in HER2-positive cases. Weighing potential benefits vs. side-effects, there seems to be no need for chemotherapy in tumors <0.5 cm. In pT1b chemotherapy may be considered, if tumors are triple negative or HER2-positive and HR-negative. In pT1c guideline-based adjuvant therapy using all therapeutic options seems to be warranted.
authors.affiliation: Breast Center, Department for Gynecology and Obstetrics and Comprehensive Cancer Center of LMU, University Hospital Munich - Grosshadern, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Kolben
authors.affiliation: Breast Center, Department for Gynecology and Obstetrics and Comprehensive Cancer Center of LMU, University Hospital Munich - Grosshadern, Ludwig-Maximilians-University, Munich, Germany. Electronic address: nadia.harbeck@med.uni-muenchen.de.
authors.forename: N
authors.initials: N
authors.lastname: Harbeck
authors.affiliation: Breast Center, Department for Gynecology and Obstetrics and Comprehensive Cancer Center of LMU, University Hospital Munich - Maistrasse, Ludwig-Maximilians-University, Munich, Germany.
authors.forename: R
authors.initials: R
authors.lastname: Wuerstlein
authors.affiliation: Munich Cancer Registry (MCR) of the Munich Cancer Center (MCC), Department of Medical Informatics, Biometry and Epidemiology (IBE), Ludwig-Maximilians-University, Munich, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Schubert-Fritschle
authors.affiliation: Head of Project Group Breast Cancer of Munich, Department for Gynecology and Obstetrics, Klinikum Landshut, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Bauerfeind
authors.affiliation: Munich Cancer Registry (MCR) of the Munich Cancer Center (MCC), Department of Medical Informatics, Biometry and Epidemiology (IBE), Ludwig-Maximilians-University, Munich, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Schrodi
authors.affiliation: Munich Cancer Registry (MCR) of the Munich Cancer Center (MCC), Department of Medical Informatics, Biometry and Epidemiology (IBE), Ludwig-Maximilians-University, Munich, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Engel
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000737:chemistry / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D017024:Chemotherapy, Adjuvant; D018450:Disease Progression; D066246:ErbB Receptors / Q000097:blood; D005260:Female; D005858:Germany; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000737:chemistry / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology; D011379:Prognosis; D016016:Proportional Hazards Models; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D012042:Registries; D015996:Survival Rate
chemical_list: D066246:ErbB Receptors; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C512478:EGFR protein, human
keywords: Breast cancer; Chemotherapy; HER2-status; Node-negative; Outcome; Small tumors