title: Impact of acellular mucin pools on survival in patients with complete pathological response to neoadjuvant treatment in rectal cancer.
abstract: BACKGROUND
  Rarely, patients with pathological complete response (PCR) after neoadjuvant chemoradiotherapy demonstrate acellular mucin pools. The prognostic significance of this finding is controversial. The objective of this study was to determine impact of acellular mucin pools on disease free and overall survival in patients with complete pathological response to neoadjuvant chemoradiotherapy in rectal cancer.
  
  
  METHODS
  One hundred and seventy two patients received neoadjuvant chemoradiotherapy for rectal cancer and underwent surgery. Patients were divided into two groups based on presence of acellular mucin pools. Locoregional failures, distant failures and deaths were compared. Expected 5 year disease free and overall survival was calculated.
  
  
  RESULTS
  Median follow-up was 36(4-94) months. Complete pathological response was identified in 35(20.3%) patients. Of these, 12(34.2%) had acellular mucin pools in resected specimen. Majority of mucin negative tumors were moderately differentiated (78% vs 25%) (P = 0.005). Median overall survival for mucin positive and mucin negative tumors was 4(1.3-5.7) and 3.3(0.1-6.3) years respectively. Expected 5 year disease free and overall survival for mucin positive and mucin negative tumors was 73% and 89% (P = 0.1) and 75% and 87% (P = 0.4).
  
  
  CONCLUSIONS
  Acellular mucin pools in rectal cancer following a PCR to neoadjuvant treatment do not impact survival.
authors: Department of Surgical Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan. Electronic address: abubakar.hafeez@yahoo.co.
authors: Abu Bakar Hafeez
authors: AB
authors: Bhatti
authors: Department of Surgical Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.
authors: Ali
authors: A
authors: Akbar
authors: Department of Surgical Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.
authors: Shahid
authors: S
authors: Khattak
authors: Department of Medical Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.
authors: Ather Saeed
authors: AS
authors: Kazmi
authors: Department of Radiation Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.
authors: Aarif
authors: A
authors: Jamshed
authors: Department of Surgical Oncology, Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan.
authors: Aamir Ali
authors: AA
authors: Syed
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000378:metabolism* / Q000401:mortality* / Q000628:therapy; D002474:Cell-Free System; D059248:Chemoradiotherapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009077:Mucins / Q000378:metabolism*; D020360:Neoadjuvant Therapy; D011379:Prognosis; D012004:Rectal Neoplasms / Q000378:metabolism* / Q000401:mortality* / Q000628:therapy
chemical_list: D009077:Mucins
keywords: Mucin; Rectal cancer; Survival