title: Should isolated peritoneal carcinomatosis from colorectal cancer be sub-classified into stage IVB in era of modern chemotherapy?
abstract: BACKGROUND
  According to the 7th edition of the TNM staging system, stage IV metastatic colorectal cancer (CRC) at the time of initial diagnosis is sub-classified into stage IVA or IVB disease. Peritoneal carcinomatosis (PC), considered to have a dismal prognosis, is exclusively sub-classified into stage IVB, even though other metastases to a sole organ are sub-classified into stage IVA, which is considered to be associated with better survival. This retrospective study was undertaken to investigate the overall survival in metastatic CRC patients, focusing on PC patients.
  
  
  METHODS
  We reviewed data on patients with metastatic CRC at initial diagnosis surgically treated between January 2006 and June 2011. A survival analysis was performed paying special attention to PC and sub-classifying patients with PC into three categories according to metastatic sites.
  
  
  RESULTS
  There were 69 stage IVA patients (IVA group) and 83 stage IVB. Among stage IVB patients, 20 had isolated PC (PC-I group), 28 had PC with one or more other sites of metastasis (PC-II group), and 35 had at least 2 metastatic without peritoneal involvement (NPC group). Of 152 stage IV patients, 132 (87 %) underwent resection of the primary tumor and 19 (12 %) underwent radical resection of metastatic disease with microscopic free margins (R0 resection) including 5/20 (25 %) patients in the PC1 group. A total of 139 patients received oxaliplatin-based chemotherapy in a palliative (n = 125), neoadjuvant (n = 3), or adjuvant setting after R0 resection (n = 11). Compared with 36.6 months in the PC-I group, median survival was 32.5 months (P = 0.48) in the IVA group, 14.7 months (P = 0.07) in the PC-II group, and 12.9 months (P < 0.01) in the NPC group.
  
  
  CONCLUSIONS
  The sub-classification of isolated PC into stage IVA instead of IVB might be more appropriate in the era of modern chemotherapy. Further investigation is warranted.
authors: Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Kawagoe, Saitama, Japan, 05hishi@saitama-med.ac.jp.
authors: H
authors: H
authors: Ishida
authors: K
authors: K
authors: Kumamoto
authors: K
authors: K
authors: Ishibashi
authors: S
authors: S
authors: Hatano
authors: T
authors: T
authors: Matsuzawa
authors: N
authors: N
authors: Okada
authors: Y
authors: Y
authors: Kumagai
authors: H
authors: H
authors: Baba
authors: N
authors: N
authors: Haga
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D061067:Antibodies, Monoclonal, Humanized / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage; D000068258:Bevacizumab; D002277:Carcinoma / Q000188:drug therapy / Q000473:pathology* / Q000556:secondary; D017024:Chemotherapy, Adjuvant; D015179:Colorectal Neoplasms / Q000473:pathology* / Q000601:surgery; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D006801:Humans; D053208:Kaplan-Meier Estimate; D002955:Leucovorin / Q000008:administration & dosage; D008113:Liver Neoplasms / Q000188:drug therapy / Q000556:secondary*; D008175:Lung Neoplasms / Q000188:drug therapy / Q000556:secondary*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D009944:Organoplatinum Compounds / Q000008:administration & dosage; D010166:Palliative Care; D010534:Peritoneal Neoplasms / Q000188:drug therapy / Q000473:pathology* / Q000556:secondary; D011379:Prognosis; D012189:Retrospective Studies
chemical_list: D061067:Antibodies, Monoclonal, Humanized; D009944:Organoplatinum Compounds; D000068258:Bevacizumab; D002955:Leucovorin; D005472:Fluorouracil
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