title: Absence of lymph nodes in the resected specimen after radical surgery for distal rectal cancer and neoadjuvant chemoradiation therapy: what does it mean?
abstract: OBJECTIVE
  The number of retrieved lymph nodes during radical surgery has been considered of great importance to ensure adequate staging and radical resection. However, this finding may not be applicable after neoadjuvant therapy in which, not only is there a decrease in lymph nodes recovered, but also a subgroup of patients with absence of lymph nodes in the resected specimen.
  
  
  METHODS
  Patients with absence of lymph nodes were compared with patients with ypN0 disease and patients with ypN+ disease.
  
  
  RESULTS
  Thirty-two patients (11 percent) had absence of lymph nodes, 171 patients (61 percent) had ypN0 disease, and 78 patients (28 percent) had ypN+ disease. Patients with absence of lymph nodes had significantly lower ypT status (ypT0-1, 40 vs. 13 percent; P<0.001) and decreased risk of perineural invasion (6 vs. 21 percent; P=0.04) compared with ypN0 patients. Five-year disease-free survival (74 percent) was similar to patients with ypN0 (59 percent; P=0.2), and both were significantly better than patients with ypN+ disease (30 percent; P<0.001).
  
  
  CONCLUSIONS
  Absence of lymph nodes retrieved from the resected specimen is associated with favorable pathologic features (ypT and perineural invasion status) and good disease-free survival rates. In this setting, absence of retrieved lymph nodes may reflect improved response to neoadjuvant chemoradiation therapy rather than inappropriate or suboptimal oncologic radicality.
authors.affiliation: Department of Gastroenterology, University of São Paulo School of Medicine, São Paulo, Brazil.
authors.forename: Angelita
authors.initials: A
authors.lastname: Habr-Gama
authors.forename: Rodrigo O
authors.initials: RO
authors.lastname: Perez
authors.forename: Igor
authors.initials: I
authors.lastname: Proscurshim
authors.forename: Viviane
authors.initials: V
authors.lastname: Rawet
authors.forename: Diego D
authors.initials: DD
authors.lastname: Pereira
authors.forename: Afonso H S
authors.initials: AH
authors.lastname: Sousa
authors.forename: Desiderio
authors.initials: D
authors.lastname: Kiss
authors.forename: Ivan
authors.initials: I
authors.lastname: Cecconello
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000473:pathology* / Q000628:therapy*; D012189:Retrospective Studies; D015996:Survival Rate