title: Daily Practice Management of pT1a-b pN0 Breast Carcinoma: A Prospective French ODISSEE Cohort Study.
abstract: BACKGROUND
  Most breast cancer (BC) tumors ≤10 mm have an excellent prognosis. The subgroups with a higher risk for distant recurrence requiring adjuvant systemic therapy are not precisely defined in current international guidelines.
  
  
  METHODS
  The OBSERVATOIRE DES PETITS CANCERS DU SEIN HER2 +/- (ODISSEE) study was a prospective, multicenter, cohort study that aimed to describe the daily adjuvant management and outcome of 616 patients with unifocal, invasive pT1a-b pN0 nonmetastatic BC who underwent surgery.
  
  
  RESULTS
  At the time of diagnosis, the median age of patients was 61 years. Tumor was detected on imaging or during a screening program in 397 patients (64.6%). Most patients (96%) underwent conservative surgery with sentinel node biopsy (89%), completed with axillary lymph node dissection in 15%. At inclusion, 82% of tumors were pT1b, 73% were pN0 (i-), 53% were Scarff-Bloom-Richardson Grade I, 91% were estrogen receptor (ER)-positive, 5% overexpressed/amplified HER2, and 5% were triple negative (TNBC). Adjuvant treatments were radiotherapy (95%), hormone therapy (82%), chemotherapy (7%), and trastuzumab (3.5%). In patients with TNBC and HER2-positive BC, chemotherapy and trastuzumab (if needed) were administered in 45% and 68%, respectively. After 5 years of follow-up, 7 patients had contralateral BC, 7 had locoregional recurrence, and 1 had distant metastasis. At 5 years, overall survival, disease-free survival, and recurrence-free survival were: 98.4% (96.9%-99.1%), 94.7% (92.4%-96.3%), and 97.1% (95.2%-98.2%), respectively.
  
  
  CONCLUSIONS
  This prospective cohort study showed that in France, the routine practice in pT1a-b pN0 breast cancers follows international standard guidelines for practice including conservative surgery followed by radiotherapy and endocrine therapy for ER-positive patients. Adjuvant chemotherapy with or without trastuzumab was used but their benefit in breast cancer of ≤10 mm remains controversial.
authors.affiliation: Claudius Regaud Institute, Institut Universitaire du Cancer de Toulouse (UICT)-Oncopole, Department of Medical Oncology and Inserm UMR 1037, Team "Cholesterol Metabolism and Therapeutic Innovations", Cancer Research Center, Toulouse, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Dalenc
authors.affiliation: Department of Pathology, Jean Perrin Institute, Clermont Ferrand, France.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Penault-Llorca
authors.affiliation: Department of Surgery, Private Institute, Aubagne, France.
authors.forename: Monique
authors.initials: M
authors.lastname: Cohen
authors.affiliation: Department of Surgery, Paoli-Calmettes Institute, Marseille, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Houvenaeghel
authors.affiliation: Breast Institute of Orangerie, Strasbourg, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Piat
authors.affiliation: Breast Institute of Orangerie, Strasbourg, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Liegeois
authors.affiliation: Department of Breast and Gynecologic Surgery, Union Clinic, Saint Jean, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Puyuelo
authors.affiliation: Department of Radiotherapy, Roanne Hospital, Roanne, France.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Suchaud
authors.affiliation: Department of Radiotherapy, Marie Curie Institute, Valence, France.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Zouai
authors.affiliation: Claudius Regaud Institute, Institut Universitaire du Cancer de Toulouse (UICT)-Oncopole, Department of Medical Oncology and Inserm UMR 1037, Team "Cholesterol Metabolism and Therapeutic Innovations", Cancer Research Center, Toulouse, France.
authors.forename: Magali
authors.initials: M
authors.lastname: Lacroix-Triki
authors.affiliation: Department of Pathology, Jean Perrin Institute, Clermont Ferrand, France.
authors.forename: Nina
authors.initials: N
authors.lastname: Radosevic-Robin
authors.affiliation: Roche, France.
authors.forename: Chahinez
authors.initials: C
authors.lastname: Benkanoun
authors.affiliation: Roche, France.
authors.forename: Hanane
authors.initials: H
authors.lastname: Attar-Rabia
authors.affiliation: Department of Breast Surgery, Oscar Lambret Anti-Cancer Center-UNICANCER, Lille, France.
authors.forename: Marie-Pierre
authors.initials: MP
authors.lastname: Chauvet
authors.affiliation: Assistance Publique Hôpitaux de Paris (AP-HP), Department of Medical Oncology, Tenon Hospital, and University of Pierre et Marie Curie (UPMC), Paris.
authors.forename: Joseph
authors.initials: J
authors.lastname: Gligorov
authors.affiliation: Assistance Publique Hôpitaux de Paris (AP-HP), Department of Radiation Oncology and Henri Mondor Breast Center, INSERM U955 E07, and University of Paris-Est Créteil (UPEC), France. Electronic address: yazid.belkacemi@hmn.aphp.fr.
authors.forename: Yazid
authors.initials: Y
authors.lastname: Belkacemi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000401:mortality / Q000473:pathology* / Q000628:therapy*; D017024:Chemotherapy, Adjuvant; D018572:Disease-Free Survival; D047628:Estrogen Receptor alpha / Q000378:metabolism; D005260:Female; D005500:Follow-Up Studies; D005602:France / Q000453:epidemiology; D006801:Humans; D008875:Middle Aged; D060787:Neoplasm Grading; D009364:Neoplasm Recurrence, Local / Q000453:epidemiology; D009367:Neoplasm Staging; D017410:Practice Guidelines as Topic; D011379:Prognosis; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D057566:Self Report; D000068878:Trastuzumab / Q000627:therapeutic use*; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D018931:Antineoplastic Agents, Hormonal; D014408:Biomarkers, Tumor; D047628:Estrogen Receptor alpha; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab; C506487:ESR1 protein, human; C508053:ERBB2 protein, human
keywords: Adjuvant treatment; Breast cancer subtypes; Conservative surgery; Endocrine therapy; Radiotherapy