title: Mucinous adenocarcinoma of the rectum: a poor candidate for neo-adjuvant chemoradiation?
abstract: BACKGROUND
  Mucinous adenocarcinoma (MA) is a distinct pathological entity associated with poor outcome. Due to different biological behavior, the response to neoadjuvant chemo-radiation (NACRT) may be inferior compared to non-mucinous tumours. In this study we compare the pathological response of mucinous tumours after NACRT.
  
  
  METHODS
  A total of 183 patients who underwent NACRT for rectal cancer were classified as mucinous and non-MAs. The dose of radiation was 45 Gy (at 1.8 Gy per fraction) delivered over five weeks with weekly 5-flourouracil (5-FU) (325 mg/m(2)) and leucovorin (20 mg/m(2)). After surgery, the pathological specimens were evaluated and staged. The data are reported as descriptive statistics and chi-square test used to determine difference in proportions.
  
  
  RESULTS
  The two varieties were comparable on the basis of the computed tomography (CT) scan in terms of tumour size and lymph node metastasis. However in terms of pathological response, it was seen that there was a higher incidence of pT4 tumours (73.5% vs. 10.7%), margin positivity (11.7% vs. 2.3%) and advanced nodal disease pN2 (29.4% vs. 9.3%) in mucinous and non-mucinous tumours respectively.
  
  
  CONCLUSIONS
  MA of the rectum show a poor response to NACRT as seen in terms of larger residual tumours, higher incidence of margin positivity, and greater residual nodal disease. Also they showed higher incidence of peritoneal and distant dissemination during NACRT. The role of NACRT in mucinous carcinoma of the rectum is of questionable benefit and needs to be examined in prospective trials.
authors.affiliation: Post Graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Vijai
authors.initials: V
authors.lastname: Simha
authors.affiliation: Post Graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Rakesh
authors.initials: R
authors.lastname: Kapoor
authors.affiliation: Post Graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Rajesh
authors.initials: R
authors.lastname: Gupta
authors.affiliation: Post Graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Amit
authors.initials: A
authors.lastname: Bahl
authors.affiliation: Post Graduate Institute of Medical Education and Research, Chandigarh, India.
authors.forename: Ritambhara
authors.initials: R
authors.lastname: Nada
keywords: Rectal cancer; adenocarcinoma; mucinous; neoadjuvant chemo-radiation (NACRT); neoadjuvant therapy
references.citation: J Clin Oncol. 2012 May 20;30(15):1770-6
references.pmid: 22493423
references.citation: Int J Oncol. 1999 Jun;14(6):1057-61
references.pmid: 10339657
references.citation: Colorectal Dis. 2006 May;8(4):283-8
references.pmid: 16630231
references.citation: Cancer. 2000 Apr 1;88(7):1739-57
references.pmid: 10738234
references.citation: Lancet Oncol. 2010 Sep;11(9):835-44
references.pmid: 20692872
references.citation: Cancer Res. 1990 Sep 15;50(18):5790-4
references.pmid: 2118420
references.citation: Int J Radiat Oncol Biol Phys. 2012 Dec 1;84(5):1159-65
references.pmid: 22580120
references.citation: Int J Colorectal Dis. 1997;12(1):19-23
references.pmid: 9112145
references.citation: Cancer. 1976 Apr;37(4):1891-1900
references.pmid: 177180
references.citation: Gastroenterol Hepatol. 2002 Nov;25(9):534-40
references.pmid: 12435303
references.citation: Int J Cancer. 2002 Nov 20;102(3):225-9
references.pmid: 12397640
references.citation: J Surg Oncol. 2000 Feb;73(2):70-4
references.pmid: 10694641
references.citation: Ann Surg. 2002 Jul;236(1):75-81
references.pmid: 12131088
references.citation: N Engl J Med. 2001 Aug 30;345(9):638-46
references.pmid: 11547717