The Role of Log Odds of Positive Lymph Nodes in Predicting the Survival after Resection for Ampullary Adenocarcinoma.

Lymph node metastasis is a important factor on survival in ampullary adenocarcinoma. Log odds of positive lymph nodes (LODDS) is a novel prognostic indicator on lymph node status. We aimed to evaluate the prognostic impact of LODDS for the patients with ampullary adenocarcinoma who underwent R0 pancreaticoduodenectomy. The study includes 42 patients.. LODDS was calculated as "log (number of metastatic lymph nodes+0.5)/(number of total harvested nodes - metastatic lymph nodes+0.5)". LODDS subgroups were created based on their LODDS value: LODDS1(LODDS≤ - 1.5), LODDS2(-1.5 < LODDS≤ - 1.0), LODDS3(-1.0 < LODDS≤ - 0.5), LODDS4(LODDS> - 0.5). The mean survival time was 72.7 ± 7.82 months. Survival rates for 1, 3 and 5 years were 93%, 65% and 45%, respectively. The mean LODDS value was -1.0466 ± 0.51. LODDS subgroups show strong correlation with Overall Survival(OS). The mean survival were 114.8, 81.8, 56.6 and 25.6 months in LODDS subgroups 1, 2, 3 and 4, respectively (Log-rank; p = 0.002), in addition LOODS values shows correlation with perineural invasion and micro vascular invasion (p = 0.015 and p = 0.001 respectively). Findings in our patient group support the hypothesis that LODDS subgroups correlate with OS, and that value of LODDS has considerable role in prediction of OS as well.