title: Magnetic resonance imaging as an early indicator of clinical outcome in patients with metastatic colorectal carcinoma treated with cetuximab or panitumumab.
abstract: We show that detection, by week-2 magnetic resonance imaging, of tumor shrinkage >10% in response to therapy with cetuximab or panitumumab for metastatic colorectal carcinoma represents an early indicator of clinical outcome because it is predictive of the prolongation of progression-free survival and overall survival.
  
  
  OBJECTIVE
  The early identification of patients with metastatic colorectal carcinoma who are likely to benefit from treatment with panitumumab or cetuximab remains of paramount importance. We evaluated whether the early tumor shrinkage assessed by magnetic resonance imaging (MRI) is predictive of long-term outcome to these epidermal growth factor receptor-targeted therapies.
  
  
  METHODS
  Thirty-nine patients with chemorefractory metastatic colorectal carcinoma were treated with cetuximab or panitumumab. The patients were evaluated by unenhanced MRI at baseline, week 2, and week 8 after the beginning of the treatment and by contrast-enhanced computed tomography within 3 months. Early response was defined as a tumor shrinkage ≥ 10% at week-2 MRI, whereas response by contrast-enhanced computed tomography was defined according to standard Response Evaluation Criteria in Solid Tumors 1.1.
  
  
  RESULTS
  At week-2 MRI, 15 (38.5%) of 39 patients had an early response. Eleven (73.3%) of these 15 early responders then presented a partial response by contrast-enhanced computed tomography, whereas none of the 24 early nonresponders obtained a partial response (P < .0005, Fisher exact test). Median progression-free survival (PFS) was 29.7 and 8 weeks in patients with or without early response, respectively (hazard ratio [HR] 0.156 [95% CI, 0.069-0.355]; P < .0001)]. The median overall survival (OS) was 80 weeks in patients with early response and 23.3 weeks in those without early response, respectively (HR 0.154 [95% CI, 0.057-0.420]; P < .00005]).
  
  
  CONCLUSIONS
  Early detection of tumor response by week-2 MRI without contrast medium is associated with a prediction of clinical outcome in patients with metastatic colorectal carcinoma treated with cetuximab or panitumumab.
authors.affiliation: The Falck Division of Oncology, Ospedale Niguarda Ca' Granda, Milan, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Ricotta
authors.forename: Angelo
authors.initials: A
authors.lastname: Vanzulli
authors.forename: Mauro
authors.initials: M
authors.lastname: Moroni
authors.forename: Barbara
authors.initials: B
authors.lastname: Colnago
authors.forename: Matteo
authors.initials: M
authors.lastname: Oriani
authors.forename: Michele
authors.initials: M
authors.lastname: Nichelatti
authors.forename: Carolina
authors.initials: C
authors.lastname: Sarnataro
authors.forename: Filippo
authors.initials: F
authors.lastname: Venturini
authors.forename: Sara
authors.initials: S
authors.lastname: Di Bella
authors.forename: Martina
authors.initials: M
authors.lastname: Maiolani
authors.forename: Maria Olga
authors.initials: MO
authors.lastname: Giganti
authors.forename: Andrea
authors.initials: A
authors.lastname: Sartore-Bianchi
authors.forename: Salvatore
authors.initials: S
authors.lastname: Siena
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D000068818:Cetuximab; D015179:Colorectal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000473:pathology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008113:Liver Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000556:secondary*; D008207:Lymphatic Metastasis; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D000077544:Panitumumab; D010534:Peritoneal Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000556:secondary*; D011379:Prognosis; D015996:Survival Rate
chemical_list: D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000077544:Panitumumab; D000068818:Cetuximab