title: Stage-Dependent Frequency of Lymph Node Metastases in Patients With Rectal Carcinoma After Preoperative Chemoradiation: Results from the CAO/ARO/AIO-94 Trial and From a Comparative Prospective Evaluation With Extensive Pathological Workup.
abstract: BACKGROUND
  For patients with ycT1/2 rectal carcinomas after neoadjuvant chemoradiotherapy, local excision instead of radical surgery has increasingly been discussed as a way to avoid postoperative morbidity associated with radical surgery.
  
  
  OBJECTIVE
  The purpose of this study was to determine the incidence of lymph node metastases in total mesorectal excision specimens with ypT0, ypT1/2, and ypT3/4 rectal cancers.
  
  
  METHODS
  This is a prospective and retrospective cohort study.
  
  
  METHODS
  This study was conducted in tertiary referral hospitals that are part of the German Rectal Cancer Study Group.
  
  
  METHODS
  A total of 479 patients with stage II and III rectal cancers treated within phase III trials of the German Rectal Cancer Study Group were evaluated. Specimens from 81 patients treated in the Working Group of Surgical Oncology/Working Group of Radiation Oncology/Working Group of Medical Oncology of the Germany Cancer Society (CAO/ARO/AIO-04) trial were prospectively studied with extensive microscopic screening of the entire mesorectum. The frequency and localization of nodal metastases were specified and compared with those of 398 patients having received neoadjuvant chemoradiation within the CAO/ARO/AIO-94 trial.
  
  
  METHODS
  Frequency and localization of mesorectal lymph node metastases in patients with ypT0, ypT1/2, or ypT3/4 cancer were measured.
  
  
  RESULTS
  A mean number of 28.0 ± 13.7 nodes were detected per specimen within the prospective group. A total of 25% of patients in the ypT1/2 group had nodal metastases compared with 40% in the ypT3/4 group. Patients with node-positive ypT1/2 had a mean number of 2.2 metastases, and 55% of these metastases were located far from the primary lesion in the proximal mesorectum. Within the CAO/ARO/AIO-94 cohort (n = 398), 19% of patients with ypT1/2 (ypT1 = 22%; ypT2 = 18%) had ypN+ status compared with 43% with ypT3/4 cancers (ypT3 = 40%; ypT4 = 73%).
  
  
  CONCLUSIONS
  Low numbers of patients with ypT0 limited the evaluation of nodal metastases in pathologic complete responders.
  
  
  CONCLUSIONS
  Even in good responders (ypT1/2), >20% of rectal carcinomas still harbored residual lymph node metastases. Local excision for patients with ycT1/2 rectal cancers would, thus, miss metastases in a considerable percentage and might involve the risk of significant undertreatment in a number of patients.
authors.affiliation: 1 Department of General, Visceral and Pediatric Surgery, University Medical Center Goettingen, Goettingen, Germany 2 Department of Pathology, Medical Care Unit Goettingen, Goettingen, Germany 3 Department of Medical Statistics, University Medical Center Goettingen, Goettingen, Germany 4 Department of Pathology, University Medical Center Goettingen, Goettingen, Germany 5 Department of Radiotherapy and Radiooncology, University Medical Center Goettingen, Goettingen, Germany 6 Institute of Pathology, University Hospital Leipzig, Leipzig, Germany 7 Department of Radiation Therapy, University of Erlangen, Erlangen, Germany 8 Department of Radiotherapy and Oncology, University of Frankfurt, Frankfurt/Main, Germany.
authors.forename: Thilo
authors.initials: T
authors.lastname: Sprenger
authors.forename: Hilka
authors.initials: H
authors.lastname: Rothe
authors.forename: Lena-Christin
authors.initials: LC
authors.lastname: Conradi
authors.forename: Tim
authors.initials: T
authors.lastname: Beissbarth
authors.forename: Anne
authors.initials: A
authors.lastname: Kauffels
authors.forename: Julia
authors.initials: J
authors.lastname: Kitz
authors.forename: Kia
authors.initials: K
authors.lastname: Homayounfar
authors.forename: Hendrik
authors.initials: H
authors.lastname: Wolff
authors.forename: Philipp
authors.initials: P
authors.lastname: Ströbel
authors.forename: Michael
authors.initials: M
authors.lastname: Ghadimi
authors.forename: Christian
authors.initials: C
authors.lastname: Wittekind
authors.forename: Rolf
authors.initials: R
authors.lastname: Sauer
authors.forename: Claus
authors.initials: C
authors.lastname: Rödel
authors.forename: Torsten
authors.initials: T
authors.lastname: Liersch
mesh_terms: D000230:Adenocarcinoma / Q000473:pathology / Q000628:therapy*; D000328:Adult; D000368:Aged; D059186:Chemoradiotherapy, Adjuvant; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011446:Prospective Studies; D012004:Rectal Neoplasms / Q000473:pathology / Q000628:therapy*; D012007:Rectum / Q000473:pathology / Q000601:surgery*; D012189:Retrospective Studies