title: Remaining cancer cells within the fibrosis after neo-adjuvant treatment for locally advanced rectal cancer.
abstract: OBJECTIVE
  To analyse the incidence and distribution of remaining cancer cells within the fibrosis induced by preoperative chemo-radiotherapy (CRT) for locally advanced rectal cancer.
  
  
  METHODS
  The histopathological specimens from 46 patients operated on with extensive surgery for locally advanced rectal cancer after CRT were examined. The extension of fibrosis in relation to the mesorectal fascia (MRF) and the distribution of cancer cells within the fibrosis was examined using routine haematoxylin-eosin staining. In addition, immunohistochemical staining with CK20 was done to examine if cancer cells were missed by routine pathological work up.
  
  
  RESULTS
  All specimens showed CRT induced fibrosis. Two specimens showed complete response without viable cancer cells (ypT0). The fibrosis was limited inside the MRF in three cases, adherent to or involved the MRF in ten cases and in 33 cases the fibrosis was obvious outside as well as inside the fascia. Twenty-one cases showed fibrosis on the surgical resection margin, and in 9 of these cancer cells were found on the surgical margin (R1, R2-resection). 37 patients had R0 resections and among those 24 showed fibrosis beyond the MFR and 13 had scattered cancer cells in the fibrosis along or outside the MRF.
  
  
  CONCLUSIONS
  The rate of remaining cancer cells within the fibrosis was high in patients with locally advanced rectal cancer treated with CRT. Frequently cancer cells were detected near the border of the fibrosis. A complete resection of the fibrosis is therefore recommended to achieve an R0 resection after neo-adjuvant treatment.
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 76 Stockholm, Sweden; Department of Surgery, Matsuda Colo-Proctology Center, 753 Irino-cho, Hamamatsu, Shizuoka 4328061, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Tanaka
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Martling
authors.affiliation: Department of Pathology, Karolinska University Hospital and Karolinska Institutet, SE-171 76 Stockholm, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Lindholm
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Holm
authors.affiliation: Department of Molecular Medicine and Surgery, Karolinska Institutet, SE-171 76 Stockholm, Sweden. Electronic address: gabriella.jansson-palmer@karolinska.se.
authors.forename: G
authors.initials: G
authors.lastname: Palmer
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D059248:Chemoradiotherapy; D005205:Fascia / Q000378:metabolism / Q000473:pathology*; D005260:Female; D005355:Fibrosis; D006801:Humans; D007150:Immunohistochemistry; D053554:Keratin-20 / Q000378:metabolism; D008297:Male; D008643:Mesentery / Q000378:metabolism / Q000473:pathology*; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D018365:Neoplasm, Residual; D012004:Rectal Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy*; D012007:Rectum / Q000378:metabolism / Q000473:pathology / Q000601:surgery*
chemical_list: C507499:KRT20 protein, human; D053554:Keratin-20
keywords: Fibrosis; Local recurrence; Locally advanced rectal cancer; Mesorectal fascia (MRF); Preoperative chemoradiotherapy (CRT)