Evaluation of N-ratio in selecting patients for adjuvant chemoradiotherapy after d2-gastrectomy.
BACKGROUND
Whether adjuvant chemoradiotherapy may contribute to improve survival outcomes after D2-gastrectomy remains controversial.


OBJECTIVE
To explore the clinical utility of N-Ratio in selecting gastric cancer patients for adjuvant chemoradiotherapy after D2-gastrectomy.


METHODS
A retrospective cohort study was carried out on gastric cancer patients who underwent D2-gastrectomy alone or D2-gastrectomy plus adjuvant chemoradiotherapy (INT-0116 protocol) at the Hospital A. C. Camargo from September 1998 to December 2008. Statistical analysis were performed using multiple conventional methods, such as c-statistic, adjusted Cox's regression and stratified survival analysis.


RESULTS
Our analysis involved 128 patients. According to c-statistic, the N-Ratio (i.e., as a continuous variable) presented "area under ROC curve" (AUC) of 0.713, while the number of metastatic nodes presented AUC of 0.705. After categorization, the cut-offs provide by Marchet et al. displayed the highest discriminating power - AUC value of 0.702. This N-Ratio categorization was confirmed as an independent predictor of survival using multivariate analyses. There also was a trend of better survival by adding of adjuvant chemoradiotherapy only for patients with milder degrees of lymphatic spread - 5-year survival of 23.1% vs 66.9%, respectively (HR = 0.426, 95% CI 0.150-1.202; P = 0.092).


CONCLUSIONS
This study confirms the N-Ratio as a tool to improve the lymph node metastasis staging in gastric cancer and suggests the cut-offs provided by Marchet et al. as the best way for its categorization after a D2-gastrectomy. In these settings, the N-Ratio appears a useful tool to select patients for adjuvant chemoradiotherapy, and the benefit of adding this type of adjuvancy to D2-gastrectomy is suggested to be limited to patients with milder degrees of lymphatic spread (i.e., NR2, 10%-25%).
Departamento de Cirurgia Abdominal, Hospital Antônio Cândido de Camargo (A. C. Camargo), São PauloSP, Brasil.
Wilson Luiz da
WL
Costa Junior
Departamento de Cirurgia Abdominal, Hospital Antônio Cândido de Camargo (A. C. Camargo), São PauloSP, Brasil.
Felipe José Fernández
FJ
Coimbra
Departamento de Cirurgia/Oncologia, Faculdade Pernambucana de Saúde, Instituto de Medicina Integral, RecifePE, Brasil.
Thales Paulo
TP
Batista
Departamento de Cirurgia Abdominal, Hospital Antônio Cândido de Camargo (A. C. Camargo), São PauloSP, Brasil.
Héber Salvador de Castro
HS
Ribeiro
Departamento de Cirurgia Abdominal, Hospital Antônio Cândido de Camargo (A. C. Camargo), São PauloSP, Brasil.
Alessandro Landskron
AL
Diniz
D000230:Adenocarcinoma / Q000401:mortality / Q000628:therapy*; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D059186:Chemoradiotherapy, Adjuvant; D015331:Cohort Studies; D018572:Disease-Free Survival; D005260:Female; D005743:Gastrectomy / Q000379:methods; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000401:mortality / Q000628:therapy*; D016896:Treatment Outcome