title: Adjuvant regimens with trastuzumab administered for small HER2-positive breast cancer in routine clinical practice.
abstract: OBJECTIVE
  Trastuzumab has proven to improve the prognosis of HER2-positive breast cancer, but the information available about its administration for small tumors is still limited. Therefore, we assessed the use of adjuvant regimens with trastuzumab for the treatment of small HER2-positive breast cancer in routine clinical practice.
  
  
  METHODS
  This observational study was conducted in patients with HER2-positive breast adenocarcinoma ≤1.5 cm who received trastuzumab-based adjuvant treatment in clinical practice. Clinical/histopathological data were retrieved from patients' medical charts.
  
  
  RESULTS
  A total of 101 evaluable patients were enrolled (median age [range], 56.7 [49.0-64.8] years; ECOG 0, 98.0 %; ductal carcinoma, 88.1 %; lymph nodes N0, 79.2 %). Only five (5.0 %) patients received neoadjuvant treatment, while all patients underwent tumor surgery. Adjuvant trastuzumab was administered at a mean (±SD) dose of 5.9 ± 1.5 mg/kg/cycle, and mostly in a three-weekly schedule (89 [89.0 %] patients). The most frequent adjuvant therapy used with trastuzumab was chemotherapy (87 [86.1 %] patients), followed by radiotherapy (63 [62.4 %] patients) and hormone therapy (52 [51.5 %] patients). Chemotherapy regimens mainly included doxorubicin, cyclophosphamide and paclitaxel/docetaxel (n = 30), docetaxel and cyclophosphamide (n = 15), docetaxel and carboplatin (n = 13). Hormone therapy mainly included letrozole (n = 17) and tamoxifen (n = 17). Nine (8.9 %) patients reported trastuzumab-related adverse events; only one allergic reaction reached grade 3 toxicity.
  
  
  CONCLUSIONS
  This study shows that trastuzumab-based adjuvant treatment of small HER2-positive breast cancer is mostly based on chemotherapy-mainly paclitaxel/docetaxel. Adjuvant administration of trastuzumab for small HER2-positive breast cancer seems to be similar to that used for larger tumors.
authors.affiliation: Department of Oncology, Complejo Hospitalario Universitario A Coruña, Xubias de Arriba, 84, 15006, A Coruña, Spain. Silvia.Antolin.Novoa@sergas.es.
authors.forename: S
authors.initials: S
authors.lastname: Antolín-Novoa
authors.affiliation: Department of Oncology, Hospital Infanta Cristina, Avenida de Elvas, S/N, 06080, Badajoz, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Blanco-Campanario
authors.affiliation: Department of Oncology, Hospital Universitario Miguel Servet, Paseo de Isabel la Católica, 1-3, 50009, Zaragoza, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Antón
authors.affiliation: Department of Oncology, Hospital General de Segovia, Carretera de Ávila, S/N, 40002, Segovia, Spain.
authors.forename: M I
authors.initials: MI
authors.lastname: Gallegos-Sancho
authors.affiliation: Department of Oncology, Hospital Quirón Madrid, Diego de Velázquez, 1, 28223, Pozuelo de Alarcón, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Pérez-Carrión
authors.affiliation: Department of Oncology, Hospital de Cabueñes, Los Prados, 395, 33394, Gijón, Spain.
authors.forename: I
authors.initials: I
authors.lastname: Peláez
authors.affiliation: Department of Oncology, Hospital de Sagunto, Avenida Ramón y Cajal, S/N, 46520, Sagunto, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Galán-Brotons
authors.affiliation: Department of Oncology, Hospital Universitario Virgen Macarena, Avenida Dr. Fedriani, 3, 41009, Seville, Spain.
authors.forename: L
authors.initials: L
authors.lastname: de la Cruz-Merino
authors.affiliation: Department of Oncology, Hospital Universitario Insular de Gran Canaria, Avenida Marítima del Sur, S/N, 35016, Las Palmas de Gran Canaria, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Murías-Rosales
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D016190:Carboplatin / Q000008:administration & dosage; D059248:Chemoradiotherapy / Q000379:methods; D017024:Chemotherapy, Adjuvant / Q000379:methods; D003430:Cross-Sectional Studies; D003520:Cyclophosphamide / Q000008:administration & dosage; D000077143:Docetaxel; D004317:Doxorubicin / Q000008:administration & dosage; D005260:Female; D006801:Humans; D000077289:Letrozole; D008875:Middle Aged; D009570:Nitriles / Q000008:administration & dosage; D017239:Paclitaxel / Q000008:administration & dosage; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics; D013629:Tamoxifen / Q000008:administration & dosage; D043823:Taxoids / Q000008:administration & dosage; D000068878:Trastuzumab / Q000627:therapeutic use*; D014230:Triazoles / Q000008:administration & dosage
chemical_list: D000970:Antineoplastic Agents; D016190:Carboplatin; D003520:Cyclophosphamide; D000077143:Docetaxel; D004317:Doxorubicin; D000077289:Letrozole; D009570:Nitriles; D017239:Paclitaxel; D018719:Erb-b2 Receptor Tyrosine Kinases; D013629:Tamoxifen; D043823:Taxoids; D000068878:Trastuzumab; D014230:Triazoles; C508053:ERBB2 protein, human
keywords: Adjuvant; Clinical practice; HER2-positive; Small breast cancer; Trastuzumab