Evaluation of N-Ratio in Selecting Patients for Adjuvant Chemoradiotherapy After D2-Gastrectomy

Abstract

-Context -Whether adjuvant chemoradiotherapy may contribute to improve survival outcomes after D2-gastrectomy remains controvertial. 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%).

Impact of lymph node ratio in selecting patients with resected gastric cancer for adjuvant therapy

“…Two previous studies had also reported the potential role of LNR to select patients for adjuvant cXRT after gastric surgery with D2 lymphadenectomy. 20,28 In turn, these findings were consistent with data reported by Kim et al in the phase III ARTIST trial in which the survival benefit of adjuvant cXRT was most pronounced among patients with LNR >0.25. 20 In contrast, Costa Junior and colleagues reported an observational study that found adjuvant cXRT to benefit patients with milder degrees of LN disease (i.e.…”

“…20–26,28,39 The present study confirmed that LNR was a strong, independent prognostic indicator of tumor prognosis relative to other risk factors. Two previous studies had also reported the potential role of LNR to select patients for adjuvant cXRT after gastric surgery with D2 lymphadenectomy.…”

“…LNR 0.10–0.25). 28 The reasons for these disparate results are likely multifactorial and related to study design and patient selection. For example, unlike the study by Kim et al, the report by Costa Junior et al was retrospective and had a smaller sample size.…”

“…LNR was evaluated as a categorical variable using the cut-off values proposed by Marchet et al to be more comparable with previous studies and categorized further into LNR ≤0.25 and LNR >0.25 after sensitivity analyses. 20,23,26–28 Perioperative details including information on CTx and cXRT were collected. Vital status and date of death or last follow-up were also collected.…”

Positive node‐ratio in curative‐intent treatment for gastric cancer is a strong independent prognostic factor for 5‐year overall survival

“…Other previous studies also took into consideration the positive N‐ratio . Studies from Nitti et al, Marchet et al, and Wu et al also addressed lymphadenectomy with >15 nodes.…”