The Effect of Lymph Node Status on Clinical Examination and After Neoadjuvant Therapy and Surgery (cN and ypN) on Long-Term Outcomes in Patients with Locally Advanced Gastric Cancer

Abstract

Introduction. This study presents a comparative analysis of the prognostic significance of the cN and ypN categories, as well as N-status dynamics after neoadjuvant therapy in patients with locally advanced gastric cancer.

Aim. To assess the prognostic value of lymph node status after neoadjuvant therapy.

Materials and Methods. At the A.F. Tsyb Medical Radiological Research Centre, 121 patients received combined treatment, including neoadjuvant therapy (chemotherapy or chemoradiotherapy) and radical surgery, as part of various phases of clinical trials. Main inclusion criteria were: morphologically verified gastric adenocarcinoma (cT3-4N0-3M0 or cT2-4N1-3M0); signed informed consent; absence of somatic contraindications and urgent tumor-related complications. The principal methods of tumor verification and staging included: esophagogastroduodenoscopy with biopsy, computed tomography of the chest and abdomen, ultrasound of the supraclavicular lymph nodes and pelvis, and endosonography. Diagnostic laparoscopy was performed in 100 % of cases.

Results. The clinical category cN+ was determined in 69 % of cases, while after neoadjuvant therapy and surgery (ypN+), this proportion decreased to 31 % (p < 0.0001), which we attribute to the effect of neoadjuvant therapy. The rate of tumor progression in the ypN0 group, regardless of the cN0 category, was 25–32 %, compared to 82–86 % in the ypN+ group (p < 0.0001), indicating an extremely unfavorable prognosis in the latter group. The highest 5-year survival rates were observed in the cN0, ypN0 group (83 %); the lowest rates were observed in the cN+, ypN+ (34 %) and cN0, ypN+ (0 %) groups. Conversion of lymph node status from cN+ to ypN0 following neoadjuvant therapy led to a significant improvement in long-term outcomes (65 vs. 34 %, p = 0.000); this result was achieved in nearly half of the patients (45 %). Multivariate analysis confirmed the independent prognostic significance of the ypN category for both overall and relapse-free survival.

Conclusion. In patients with locally advanced gastric cancer, the ypN category after neoadjuvant therapy has significantly greater prognostic value compared to the clinical cN category. Downstaging of lymph node status (cN+ → ypN0) is crucial for a favorable prognosis and determines the effectiveness of neoadjuvant therapy.