title: A proposed new method for assessing the pathological response to chemotherapy in resected colorectal liver metastases.
abstract: BACKGROUND
  Pathological response (PR) to preoperative chemotherapy for colorectal liver metastases (CLM) is recognised as a prognostic factor of outcome. However, the optimal system to assess this parameter is still debated. This study focuses on current methods and proposes a possibly better method for assessing PR.
  
  
  METHODS
  Among 223 patients resected for CLM between 2004 and 2011, after more than three cycles of chemotherapy, the percentage of tumour cells, necrosis and fibrosis, and the tumour regression grade were assessed for each of 802 nodules. Pathological response was evaluated according to validated methods and their combinations. A new method combined the percentage of tumour cells and the size of all nodules as follows: , where n is each separate nodule, % is the percentage of remaining tumour cells within nodule n (%) and s is the size of nodule n (cm).The prognostic value of each method was calculated.
  
  
  RESULTS
  After a median follow-up of 47 months (3-106), the cumulative 5-year overall survival rate after liver resection was 59%. The proposed method categorised as follows: 0 residual tumour; 0.1-6-cm residual tumour; >6-cm residual tumour, and necrosis rate >50% stratified prognosis (P=0.0027; P=0.02), while the other methods did not. At multivariate analysis, our method remained an independent predictor of outcome (P=0.001).
  
  
  CONCLUSIONS
  Combining the percentage of tumour cells multiplied by the size of each separate tumour seems to be a better method for assessing PR. External validation is required.
authors: 1] AP-HP Hôpital Paul Brousse, Laboratoire d'Anatomie Pathologique, Villejuif, France [2] Inserm U785, Université Paris-Sud, Villejuif, France.
authors: M
authors: M
authors: Sebagh
authors: AP-HP Hôpital Paul Brousse, Centre Hépatobiliaire, Villejuif, France.
authors: M-A
authors: MA
authors: Allard
authors: 1] Inserm U785, Université Paris-Sud, Villejuif, France [2] AP-HP Hôpital Paul Brousse, Centre Hépatobiliaire, Villejuif, France.
authors: A S
authors: AS
authors: Cunha
authors: 1] AP-HP Hôpital Paul Brousse, Centre Hépatobiliaire, Villejuif, France [2] University Medical Center Utrecht, Utrecht, The Netherlands.
authors: A
authors: A
authors: Ruiz
authors: AP-HP Hôpital Paul Brousse, Centre Hépatobiliaire, Villejuif, France.
authors: R
authors: R
authors: Araujo
authors: AP-HP Hôpital Paul Brousse, Laboratoire de Biochimie, Villejuif, France.
authors: A
authors: A
authors: Lemoine
authors: AP-HP Hôpital Paul Brousse, Centre Hépatobiliaire, Villejuif, France.
authors: B
authors: B
authors: Paule
authors: AP-HP Hôpital Paul Brousse, Centre Hépatobiliaire, Villejuif, France.
authors: V
authors: V
authors: Delvart
authors: AP-HP Hôpital Paul Brousse, Centre Hépatobiliaire, Villejuif, France.
authors: D
authors: D
authors: Cherqui
authors: 1] Inserm U785, Université Paris-Sud, Villejuif, France [2] AP-HP Hôpital Paul Brousse, Centre Hépatobiliaire, Villejuif, France.
authors: E
authors: E
authors: Vibert
authors: 1] AP-HP Hôpital Paul Brousse, Centre Hépatobiliaire, Villejuif, France [2] Inserm UMRS 776, Université Paris-Sud, Villejuif, France.
authors: R
authors: R
authors: Adam
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D061067:Antibodies, Monoclonal, Humanized / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000068258:Bevacizumab; D000068818:Cetuximab; D015331:Cohort Studies; D015179:Colorectal Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000556:secondary / Q000601:surgery; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D016896:Treatment Outcome
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D000068258:Bevacizumab; D000068818:Cetuximab