title: Complete remission in metastatic breast cancer: expecting the unexpected-results of a cross-sectional study.
abstract: BACKGROUND
  Complete response (CR) in metastatic breast cancer (MBC) is rare. This study aims at analyzing the characteristics and outcome of MBC patients achieving CR.
  
  
  METHODS
  We performed a cross-sectional analysis of clinical data from a consecutive series of MBC patients admitted at the Division of Medical Oncology of Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy, achieving CR following treatment for systemic disease and with at least 2 years of follow-up.
  
  
  RESULTS
  Seventy-six MBC patients with CR were identified during a calendar year. 47 patients (61.8%) achieved CR more than once, for a total of 123 cases. Median age at MBC diagnosis was 56 years (range 30-76). 52 patients (68.4%) presented with recurrent disease, 24 (31.6%) with de novo metastatic disease. The majority of patients (80.3%) had hormone receptor (HR) positive and 26 (34.2%) had HER2 overexpressing MBC. 54 patients (71.1%) had only one site of metastatic disease. 33 patients (43.4%) received a local approach as part of their treatment and 67 (54.5%) achieved CR during maintenance therapy. CRs were durable, as after a median follow-up of 8.3 years (interquartile range 5.8-11.0 years) 42 patients (55.3%) were alive with no evidence of disease.
  
  
  CONCLUSIONS
  Durable CRs can occur after systemic therapy alone or after combined systemic and local treatments. Most cases presented CR in the presence of limited disease spreading, not necessarily on first-line therapy. Our study highlights the crucial role of multidisciplinary approach to MBC and the benefit of maintenance treatment.
authors.affiliation: Division of Medical Oncology 1, Fondazione IRCCS Istituto Nazionale dei Tumori, via G. Venezian 1, 20133, Milan, Italy. giulia.galli@istitutotumori.mi.it.
authors.forename: Giulia
authors.identifier: http://orcid.org/0000-0001-7287-4848
authors.initials: G
authors.lastname: Galli
authors.affiliation: Department of Cancer Biology and Genetics, The Ohio State University, 460 West 12th Avenue, Columbus, OH, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Tessari
authors.affiliation: Oncology Department, IRCCS Istituto di Ricerche Farmacologiche Mario Negri, Via La Masa 19, 20156, Milan, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Porcu
authors.affiliation: Division of Medical Oncology 1, Fondazione IRCCS Istituto Nazionale dei Tumori, via G. Venezian 1, 20133, Milan, Italy.
authors.forename: Giacomo
authors.initials: G
authors.lastname: Bregni
authors.affiliation: Department of Pathology 1, Fondazione IRCCS Istituto Nazionale dei Tumori, Via G. Venezian 1, 20133, Milan, Italy.
authors.forename: Biagio
authors.initials: B
authors.lastname: Paolini
authors.affiliation: Department of Pathology 1, Fondazione IRCCS Istituto Nazionale dei Tumori, Via G. Venezian 1, 20133, Milan, Italy.
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Carcangiu
authors.affiliation: Department of General Surgery 3, Fondazione IRCCS Istituto Nazionale dei Tumori, Via G. Venezian 1, 20133, Milan, Italy.
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Gennaro
authors.affiliation: Department of Radiation Oncology 1, Fondazione IRCCS Istituto Nazionale dei Tumori, Via G. Venezian 1, 20133, Milan, Italy.
authors.forename: Maria Carmen
authors.initials: MC
authors.lastname: De Santis
authors.affiliation: Department of Radiation Oncology 1, Fondazione IRCCS Istituto Nazionale dei Tumori, Via G. Venezian 1, 20133, Milan, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Lozza
authors.affiliation: Division of Medical Oncology 1, Fondazione IRCCS Istituto Nazionale dei Tumori, via G. Venezian 1, 20133, Milan, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: de Braud
authors.affiliation: Division of Medical Oncology 1, Fondazione IRCCS Istituto Nazionale dei Tumori, via G. Venezian 1, 20133, Milan, Italy.
authors.forename: Serena
authors.initials: S
authors.lastname: Di Cosimo
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000188:drug therapy* / Q000378:metabolism / Q000556:secondary; D018275:Carcinoma, Lobular / Q000188:drug therapy* / Q000378:metabolism / Q000556:secondary; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012074:Remission Induction; D012189:Retrospective Studies; D015996:Survival Rate
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human
keywords: Complete response; Cross-sectional study; Disease progression; Metastatic breast cancer; Time to progression