Prognostic significance of platelet-lymphocyte ratio in extrapulmonary neuroendocrine carcinoma

Background Extrapulmonary neuroendocrine carcinoma (EP-NEC) is an aggressive type of cancer with poor prognosis. Although several biological and histological markers are prognostic factors in NEC, the correlation between prognosis and systemic inflammation markers, such as the neutrophil-lymphocyte ratio (NLR) and platelet-lymphocyte ratio (PLR), is unclear. This study evaluated the association between NLR or PLR and median overall survival (OS) or progression-free survival (PFS) in EP-NEC. Methods We retrospectively analyzed the clinical data from patients with unresectable or metastatic EP-NECs who received platinum-based chemotherapy at Chonnam National University Hwasun Hospital from August 2007 to March 2019. The cut-off values for NLR and PLR were 3 and 160, respectively. Results In total, 38 patients were analyzed. Both NLR and PLR at diagnosis had no significant associations with the response to initial chemotherapy. However, in the high-PLR group, median overall survival (OS) and progression-free survival (PFS) were poorer than those in the low-PLR group (high vs. low: 10.6 vs. 17.1 months, log-rank p = 0.007 and 4.1 vs. 9.3 months, log-rank p = 0.032, respectively). However, the high-NLR group had insignificantly poorer median OS and PFS than the low-NLR group. In the multivariate analysis, high PLR and LDH were independent prognostic factors for median OS and PFS. Conclusions High PLR was associated with shorter survival of EP-NEC patients receiving platinum-based chemotherapy. Therefore, PLR may be an independent prognostic factor in EP-NEC.