Prognostic implications of the distribution of lymph node metastases in rectal cancer after neoadjuvant chemoradiotherapy.
OBJECTIVE
After preoperative chemoradiotherapy of rectal cancer, the number of retrievable and metastatic lymph nodes is decreased. The current TNM classification is based on number and not location of lymph node metastases and may understage disease after chemoradiotherapy. The aim of this study was to examine the prognostic significance of location of involved lymph nodes in rectal cancer patients after preoperative chemoradiotherapy.


METHODS
We prospectively examined whole-mount specimens from 121 patients with uT3-4 and/or N+ rectal cancer who received preoperative chemoradiotherapy followed by resection. Location of involved lymph nodes was compared with median number of lymph nodes involved as well as presence of distant metastasis at presentation.


RESULTS
Lymph node metastases were detected in 37 patients (31%). Thirteen patients with lymph node involvement along major supplying vessels (proximal lymph node metastases) had a significantly higher rate of distant metastatic disease at time of surgery than patients without proximal lymph node involvement (P < .001); median number of lymph nodes involved was two for patients with proximal lymph node metastases and 1.5 for patients with mesorectal lymph node involvement alone.


CONCLUSIONS
Our data suggest that, after preoperative chemoradiotherapy, proximal lymph node involvement is associated with a high incidence of metastatic disease at time of surgery. Because the median number of involved lymph nodes is low after preoperative chemoradiotherapy, the TNM staging system may not provide an accurate assessment of metastatic disease. Therefore, the ypTNM staging system should incorporate distribution as well as number of lymph node metastases after preoperative chemoradiotherapy for rectal cancer.
Leibold
Tobias
T
Department of Surgery, Memorial Sloan-Kettering Cancer Center, 1275 York Ave, Room C-1077, New York, NY 10021, USA.
Shia
Jinru
J
Ruo
Leyo
L
Minsky
Bruce D
BD
Akhurst
Timothy
T
Gollub
Marc J
MJ
Ginsberg
Michelle S
MS
Larson
Steven
S
Riedel
Elyn
E
Wong
W Douglas
WD
Guillem
José G
JG
D000230:Adenocarcinoma / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D000328:Adult; D000368:Aged; D017024:Chemotherapy, Adjuvant; D019160:Endosonography; D005260:Female; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000187:drug effects* / Q000473:pathology / Q000528:radiation effects*; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy* / Q000601:surgery; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed