title: Clinical significance of mucinous rectal adenocarcinoma following preoperative chemoradiotherapy and curative surgery.
abstract: OBJECTIVE
  To investigate the efficacy and prognosis associated with preoperative chemoradiotherapy in patients with locally advanced mucinous rectal cancer (MRC).
  
  
  METHODS
  Our analysis included 412 patients who underwent preoperative chemoradiotherapy and curative surgery for locally advanced rectal cancer. Among these patients, 30 had MRC and 382 had nonmucinous rectal cancer (NMRC). Tumor downstaging, defined as a lower pathologic stage than clinical stage, and survival were compared between MRC and NMRC.
  
  
  RESULTS
  Increased frequency of cT4 disease was seen in MRC compared to NMRC (23.3% vs 8.9%, p = 0.021). Complete pathologic response rate and tumor downstaging rate were 0% and 23.3% in MRC and 15.4% and 52.4% in NMRC, respectively (p = 0.025 and p = 0.002). There was no significant difference in disease-free survival between the 2 groups (62.1% vs 75.0% at 5 years, p = 0.170), while there was a significantly lower overall survival in MRC vs NMRC (67.4% vs 88.0% at 5 years, respectively; p = 0.012). When analyzed by stage, the overall survival difference between MRC and NMRC was significant in the cT3 group (71.1% vs 89.1% at 5 years, p = 0.047) and marginally significant in the cT4 group (51.4% vs 74.5% at 5 years, p = 0.053), but not significant in subgroups with the same pathologic stage.
  
  
  CONCLUSIONS
  Mucinous rectal cancer is related to a lower response rate to chemoradiotherapy and poorer prognosis compared to NMRC, even when corrected for clinical stage. The poor prognosis in MRC might be associated with poor responsiveness to preoperative chemoradiotherapy.
authors.affiliation: Department of Radiation Oncology, Samsung Changwon Hospital, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Tae Gyu
authors.initials: TG
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Won
authors.initials: W
authors.lastname: Park
authors.affiliation: Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Doo Ho
authors.initials: DH
authors.lastname: Choi
authors.affiliation: Department of Radiation Oncology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Hee Chul
authors.initials: HC
authors.lastname: Park
authors.affiliation: Department of Pathology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Seok-Hyung
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Yong Beom
authors.initials: YB
authors.lastname: Cho
authors.affiliation: Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Seong Hyeon
authors.initials: SH
authors.lastname: Yun
authors.affiliation: Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Hee Cheol
authors.initials: HC
authors.lastname: Kim
authors.affiliation: Department of Surgery, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Woo Yong
authors.initials: WY
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Jeeyun
authors.initials: J
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Joon Oh
authors.initials: JO
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Young Suk
authors.initials: YS
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Ho Yeong
authors.initials: HY
authors.lastname: Lim
authors.affiliation: Department of Internal Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Won Ki
authors.initials: WK
authors.lastname: Kang
authors.affiliation: Department of Surgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul - Republic of Korea.
authors.forename: Ho-Kyung
authors.initials: HK
authors.lastname: Chun
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000473:pathology* / Q000628:therapy*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000069287:Capecitabine / Q000008:administration & dosage; D059248:Chemoradiotherapy; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005260:Female; D005472:Fluorouracil / Q000008:administration & dosage; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D009367:Neoplasm Staging; D011379:Prognosis; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome
chemical_list: D000069287:Capecitabine; D005472:Fluorouracil