title: Worse histological grade of proximal colorectal tumors and its relation with stage.
abstract: OBJECTIVE
  Accumulated data seem to support the concept that proximal and distal colorectal cancers (CRC) should be considered as different disease entities. We investigated a particular aspect of this assumption by examining variation of stage and grade distribution according to tumor site in a Greek patients' group.
  
  
  METHODS
  A total of 200 cases having had undergone surgery for primary CRC was retrospectively analysed. Fifty-seven proximal tumors were compared to 143 distal lesions regarding tumor stage (TNM I-IV) and grade of differentiation (well, moderate and poor). Grade distribution by site was also examined within each particular stage and within additional stage categories (I-II, III-IV, I-III, II-IV, II-III).
  
  
  RESULTS
  There was an almost significant trend of distal tumors for earlier stage (I) presentation (p=0.055), whereas proximal cancers were more frequently diagnosed with stages II-III (p=0.08). Poorly differentiated lesions displayed a strong predilection for proximal site (p=0.002), while tumors with moderate differentiation were preferentially found distally (p=0.001). Such segmental differences in grade distribution were also ascertained within most particular stages and all additional stage subsets (especially the last three). Moreover, both the proximal and the poorly differentiated lesions showed a parallel decrease in their incidence during the study period.
  
  
  CONCLUSIONS
  The consistently recorded worse histological pattern of proximal tumors implies a different biological behavior of these lesions possibly due to distinct tumorigenic pathways involved in their development, whereas their tendency for late stage presentation demands further investigation before considered supportive to this concept.
authors.affiliation: Department of Surgery, Athens Medical Center, Greece. ppapagiorg@teiath.gr
authors.forename: P C
authors.initials: PC
authors.lastname: Papagiorgis
authors.forename: A E
authors.initials: AE
authors.lastname: Zizi
authors.forename: S
authors.initials: S
authors.lastname: Tseleni
authors.forename: I N
authors.initials: IN
authors.lastname: Oikonomakis
authors.forename: L
authors.initials: L
authors.lastname: Sofras
authors.forename: N I
authors.initials: NI
authors.lastname: Nikiteas
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D012189:Retrospective Studies