P-083 - Prognostic determinants in gastric cancer survival - the importance of metastatic lymph node ratio

Date 04 July 2015
Event WorldGI 2015
Session Posters
Topics Gastric Cancer
Pathology/Molecular Biology
Basic Scientific Principles
Presenter A. Nogueira
Citation Annals of Oncology (2015) 26 (suppl_4): 1-100. 10.1093/annonc/mdv233
Authors A. Nogueira1, A. Garcia1, N. Saraiva1, P. Jacinto2, M. Marques3, N. Bonito1, J. Ribeiro1, H. Gervasio1
  • 1Portuguese Oncology Institute of Coimbra, Coimbra/PT
  • 2Instituto Português de Oncologia Francisco Gentil, Coimbra/PT
  • 3Portuguese Institute of Oncology Coimbra, Coimbra/PT

Abstract

Introduction

Gastric cancer is the fifth most common malignancy and the third leading cause of cancer death worldwide. Adjuvant chemoradiotherapy contributes to improve survival outcomes after gastrectomy. Our aim was to evaluate survival data in patients with gastric cancer after postoperative adjuvant chemoradiotherapy in relation to survival determinants emphasizing the metastatic lymph node ratio.

Methods

We retrospectively reviewed data from 61 patients diagnosed with gastric cancer between 2006-2012 who underwent gastrectomy plus adjuvant chemoradiotherapy. Treatment consisted of two cycles of Lv5Fu2 before radiotherapy, continuous 5-Fu infusion during radiotherapy and 6 cycles after radiotherapy (45 Gy/25 fractions/5 weeks). As survival determinants we consider: metastatic lymph node ratio, establishing two distinct groups - group 1 equal or inferior to 26% and group 2 superior to 26%, age at diagnosis, gender, tumor location, T and N-stage, grade of differentiation, histologic subtype (diffuse, intestinal, undetermined type), surgical procedure (radical or subtotal gastrectomy) and completion of adjuvant therapy. Survival analysis was made by Kaplan-Meier method.

Results

In this population, median age was 61 years old (range, 43 to 78) and most were male (60. 7%). Tumors were predominantly located in the pyloric antrum (52. 5%). Subtotal gastrectomy was performed in 73.8%. Concerning pathologic stage, pT1, pT2, pT3 and pT4 were diagnosed in 6.6%, 29.5%, 49.2% and 14.8% of patients and pN0, pN1, pN2 and pN3 in 31.1%, 39.3%, 21.3% and 8.2%, respectively. In relation to histologic subtypes, 36% of the patients were classified with intestinal type and 34.4% with diffuse type. Around 36% were grade 1, 24% grade 2 and 40% grade 3. Most patients had at least 15 lymph nodes excised (68. 9%). The average of lymph nodes removed was 19.2, and the average of metastatic lymph node was 3.51 (range, 0 to 19). Group 1 included 47 patients and group 2, 14 patients. 56% of patients completed adjuvant chemoradiotherapy as predicted. In this population 5-year-overall survival (OS) was 74. 1% and progression free survival (PFS) was 69.7%. OS and PFS had no statistical significant difference when taking into consideration age, tumor location, surgical procedure, pT stage, histologic subtype, grade of differentiation or completion of adjuvant therapy. Considering gender, we found a significant difference on OS between female and male (89% versus 63. 8%, p = 0.045), but not on five-year PFS (66.6% versus 75.8%, p = 0.537). We also found an impact on PFS but not on OS, for those with more than 14 lymph nodes versus less than 15 lymph nodes removed (84.4% versus 63.1%, p = 0.045). For pN stage a significant difference was confirmed for five-year – OS (p= 0.002) and PFS (p < 0.0001). Metastatic lymph node ratio had also influence in the OS and PFS: OS: group 1 – 87.5%, group 2 – 27.6%, p < 0.0001; PFS: group 1 – 86.1%, group 2 – 21.4%, p < 0.0001.

Conclusion

Our findings emphasize the prognostic value of metastatic lymph node ratio, leading us to consider that it might be time to think about improving current prognostic staging systems.