lymph node ratio as a prognostic factor in patients with stage III rectal cancer treated with total mesorectal excision followed by chemoradiotherapy.
OBJECTIVE
To investigate the prognostic impact of lymph node ratio (LNR) on survival in the patients with Stage III rectal cancer.


METHODS
We retrospectively reviewed the data of 421 consecutive patients who underwent total mesorectal excision followed by chemoradiotherapy for rectal cancer from 1996 to 2006. The 232 patients with positive lymph nodes (LNs) were divided into four groups according to LNR quartiles: LNR <or=0.1 (n = 69), <or=0.2 (n = 49), <or=0.4 (n = 54), and >0.4 (n = 60). The association between LNR and survival was evaluated by the Kaplan-Meier method and multivariate analysis with covariates of prognostic significance in univariate analysis.


RESULTS
The median numbers of examined and positive LNs were 17 and 3, respectively, and the median LNR was 0.20 (range, 0.03-1). There was a strong correlation between the number of positive LNs and LNR (r = 0.724, p < 0.001). After a median follow-up of 53 months (range, 9-138 months), the actuarial overall survival and disease-free survival rates at 5 years were 69% and 56%, respectively. The 5-year survival rate decreased as LNR increased (<or=0.1, 89%; <or=0.2, 67%; <or=0.4, 64%; >0.4, 50%; p < 0.001). Lymph node ratio was also a significant prognostic factor on Cox regression analysis (<or=0.1, hazard ratio [HR] = 1; <or=0.2, HR = 1.3, p = 0.623; <or=0.4, HR = 2.4, p = 0.047; >0.4, HR = 3.7, p = 0.005). Lymph node ratio had a prognostic effect on overall survival in subgroups of patients with N1 (p = 0.032) and N2 (p = 0.034) tumors.


CONCLUSIONS
Lymph node ratio was the most significant predictor of survival in the patients with Stage III rectal cancer who had undergone postoperative chemoradiation.
Kim
Young Seok
YS
Department of Radiation Oncology, Asan Medical Center, University of Ulsan, Seoul, Korea.
Kim
Jong Hoon
JH
Yoon
Sang Min
SM
Choi
Eun Kyung
EK
Ahn
Seung Do
SD
Lee
Sang-Wook
SW
Kim
Jin Cheon
JC
Yu
Chang Sik
CS
Kim
Hee Chul
HC
Kim
Tae Won
TW
Chang
Heung Moon
HM
D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D017024:Chemotherapy, Adjuvant; D003131:Combined Modality Therapy / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008197:Lymph Node Excision; D008198:Lymph Nodes / Q000473:pathology*; D008207:Lymphatic Metastasis / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis; D018714:Radiotherapy, Adjuvant; D012004:Rectal Neoplasms / Q000188:drug therapy / Q000401:mortality* / Q000473:pathology* / Q000532:radiotherapy / Q000601:surgery; D012007:Rectum / Q000601:surgery; D012189:Retrospective Studies; D016019:Survival Analysis; D055815:Young Adult