title: Long-term results of treatment of advanced dermatofibrosarcoma protuberans (DFSP) with imatinib mesylate - The impact of fibrosarcomatous transformation.
abstract: BACKGROUND
  Dermatofibrosarcoma protuberans (DFSP) is rare, infiltrating dermal neoplasm, characterized by indolent growth and low probability of metastases. The first effective systemic therapy in DFSP introduced into clinical practice was imatinib, demonstrating high activity in advanced cases. The aim of the study was to perform an analysis of patients with advanced DFSP treated with imatinib, with or without surgery, in routine clinical practice with long-term follow-up.
  
  
  METHODS
  We analyzed the data of 31 Caucasian patients (14 male, 17 female; median age 56 years) with locally advanced/initially inoperable and/or metastatic DFSP who started therapy with imatinib at initial dose 800 mg daily between 12/2004 and 07/2014. All diagnoses were confirmed cytogenetically for the presence of specific COL1A1-PDGFB fusion. Median follow-up time was 5.3 years.
  
  
  RESULTS
  Metastases were present in 15 cases (8 - lungs, 5 - soft tissue, 2 - lymph nodes). Fibrosarcomatous transformation (FS-DFSP) was confirmed in 16 patients (52%). 5-year progression-free survival (PFS) rate was 58% (median 6.8 years), 5-year overall survival (OS) rate was 64% (median time for OS was not reached). The shorter PFS and OS correlated with FS-DFSP and presence of metastatic disease. 5-year PFS rate was 93% for classic DFSP and 33% for FS-DFSP. The best overall responses were: 21 partial responses (68%, including 8 FS-DFSP, but the responses were shorter than for classic DFSP), 6 stable disease (19%) and 4 progressive diseases (13%). Thirteen patients (47%) underwent resection of residual disease and nine of them remained free of disease, although imatinib was discontinued. Median survival after progression on imatinib was 19 months, and longer survival were observed only in cases were rescue surgery/radiotherapy was possible.
  
  
  CONCLUSIONS
  Our results indicate the long-term activity of imatinib in therapy of inoperable and/or metastatic cases of DFSP, including FS-DFSP. Some DFSP patients initially evaluated as unresectable/metastatic or necessitating mutilating surgery turned resectable after imatinib therapy and this rational approach leading to complete remission maybe potentially curative.
authors.affiliation: Department of Soft Tissue/Bone Sarcoma and Melanoma, Maria Sklodowska-Curie Memorial Cancer Center, Institute of Oncology, Warsaw Poland. Electronic address: piotr.rutkowski@coi.pl.
authors.forename: P
authors.initials: P
authors.lastname: Rutkowski
authors.affiliation: Department of Soft Tissue/Bone Sarcoma and Melanoma, Maria Sklodowska-Curie Memorial Cancer Center, Institute of Oncology, Warsaw Poland.
authors.forename: A
authors.initials: A
authors.lastname: Klimczak
authors.affiliation: Department of Soft Tissue/Bone Sarcoma and Melanoma, Maria Sklodowska-Curie Memorial Cancer Center, Institute of Oncology, Warsaw Poland.
authors.forename: I
authors.initials: I
authors.lastname: Ługowska
authors.affiliation: Department of Oncology, Cardiooncology and Internal Medicine, Maria Sklodowska-Curie Memorial Cancer Center, Institute of Oncology, Warsaw Poland.
authors.forename: B
authors.initials: B
authors.lastname: Jagielska
authors.affiliation: Department of Pathology, Maria Sklodowska-Curie Memorial Cancer Center, Institute of Oncology, Warsaw Poland.
authors.forename: M
authors.initials: M
authors.lastname: Wągrodzki
authors.affiliation: Center for Human Genetics, KU, Leuven, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Dębiec-Rychter
authors.affiliation: Department of Pathology, Maria Sklodowska-Curie Memorial Cancer Center, Institute of Oncology, Warsaw Poland.
authors.forename: B
authors.initials: B
authors.lastname: Pieńkowska-Grela
authors.affiliation: Department of Soft Tissue/Bone Sarcoma and Melanoma, Maria Sklodowska-Curie Memorial Cancer Center, Institute of Oncology, Warsaw Poland.
authors.forename: T
authors.initials: T
authors.lastname: Świtaj
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D002471:Cell Transformation, Neoplastic; D018223:Dermatofibrosarcoma / Q000188:drug therapy* / Q000556:secondary; D018572:Disease-Free Survival; D005121:Extremities; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000188:drug therapy* / Q000473:pathology; D006801:Humans; D000068877:Imatinib Mesylate / Q000627:therapeutic use*; D008175:Lung Neoplasms / Q000188:drug therapy* / Q000556:secondary; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000188:drug therapy* / Q000473:pathology; D012983:Soft Tissue Neoplasms / Q000188:drug therapy* / Q000556:secondary; D060726:Torso; D016896:Treatment Outcome; D055815:Young Adult
chemical_list: D000970:Antineoplastic Agents; D000068877:Imatinib Mesylate
keywords: Dermatofibrosarcoma protuberans; Fibrosarcomatous transformation; Imatinib