title: [Effect radiotherapy on postoperative staging and residual tumor cell density in rectal cancers].
abstract: OBJECTIVE
  To determine predictive factors and prognostic value of tumor downstaging and sterilization after preoperative radiotherapy for rectal cancer.
  
  
  METHODS
  Between 1977 and 1994, 167 patients with a histologically proven adenocarcinoma underwent preoperative radiotherapy (median dose, 44 Gy; mean time before surgery, 5 weeks). Pathologic specimens were reviewed by the same pathologist in order to specify the modified Astler Coller classification (MAC) and to quantify residual tumor cell density (RTCD).
  
  
  RESULTS
  According to the MAC, there were nine stage 0 (5%), 10 stage A (6%), 103 stage B1-B3 (62%) and 45 stage C1-C3 (27%) tumors. Seventeen per cent and 56% of the patients who received a dose > or = 44 Gy presented with stage 0-A and stage B1-B3 tumors, respectively, compared to 4 and 69% of those who received a dose < 44 Gy (P = 0.04). Tumor differentiation and a longer interval before surgery were significantly associated with more frequent downstaging. According to the RTCD, 62 tumors (37%) showed no or only rare foci of residual tumor cells; 62 (37%) showed an intermediate RTCD and 43 (26%) a high RTCD. No predictive factor of RTCD was statistically significant. Only post-operative staging was a significant prognostic factor (P < 0.01).
  
  
  CONCLUSIONS
  The favourable influence of higher doses of preoperative radiotherapy on pathologic stage has been observed. Tumor differentiation and time before surgery were the other significant predictive factors of tumor downstaging. Even after preoperative radiotherapy, post-operative staging retained its prognostic value.
authors.affiliation: Unité de traitement des cancers digestifs, clinique Sainte Catherine, BP 846, Avignon, France.
authors.forename: C
authors.initials: C
authors.lastname: Berger
authors.forename: A
authors.initials: A
authors.lastname: de Muret
authors.forename: P
authors.initials: P
authors.lastname: Garaud
authors.forename: S
authors.initials: S
authors.lastname: Chapet
authors.forename: P
authors.initials: P
authors.lastname: Bourlier
authors.forename: A
authors.initials: A
authors.lastname: Reynaud-Bougnoux
authors.forename: E
authors.initials: E
authors.lastname: Dorval
authors.forename: L
authors.initials: L
authors.lastname: de Calan
authors.forename: N
authors.initials: N
authors.lastname: Huten
authors.forename: O
authors.initials: O
authors.lastname: Le Floch
authors.forename: G
authors.initials: G
authors.lastname: Calais
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy* / Q000628:therapy; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor; D002470:Cell Survival / Q000528:radiation effects*; D003131:Combined Modality Therapy; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009362:Neoplasm Metastasis; D009367:Neoplasm Staging; D012004:Rectal Neoplasms / Q000473:pathology / Q000532:radiotherapy* / Q000628:therapy; D012189:Retrospective Studies; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor