Serum Lactate Dehydrogenase is a Predictive Biomarker in Oropharyngeal Cancer Patients Undergoing Radiotherapy.

<bold>Purpose/objective(s): </bold>The present study aimed to evaluate prognostic factors, particularly with respect to their role in establishing distinct prognostic subsets of human papillomavirus (HPV)-positive and -negative oropharyngeal cancer (OPC).<bold>Materials/methods: </bold>This study retrospectively evaluated 101 patients with OPC who underwent radiotherapy (RT) alone or chemoradiotherapy (CRT) at our institution between August 2008 and December 2018. Whole neck RT (44.0-50.0 Gy/22-25 fractions) was delivered by intensity-modulated RT (IMRT), followed by boost IMRT to high-risk clinical target volume (total dose of 70.0 Gy/35 fractions). Seventy patients (69.3%) received concurrent chemotherapy. Clinical factors which were potentially associated with prognosis were analyzed. Receiver-operating characteristic curve analysis was adopted to determine the most appropriate cut-off points of hematological biomarkers including the serum lactate dehydrogenase (LDH), neutrophil-to-lymphocyte ratio (NLR), lymphocyte-to-monocyte ratio (LMR), C-reactive protein/ albumin ratio (CRP/Alb).<bold>Results: </bold>The median follow-up period of the surviving patients was 68 (range; 8-164) months. The 5-year overall survival rate were 69.8%. Univariate analyses revealed that poor survival was associated with gender of male, smoking≥30 pack years, Eastern Cooperative Oncology Group performance status≥1, tumor-node-metastasis (TNM) stage of III-IV (8th edition), HPV-negative, LDH≥202, CRP/Alb≥0.15, LMR < 2.90. In multivariate analyses, poor survival was independently correlated with smoking ≥30 pack years (P < 0.01), LDH ≥202 (P = 0.02). Patients were divided into two groups according to HPV status as HPV-positive and negative OPC and potential prognostic factors were assessed in univariate analyses. In HPV-positive OPC patients, poor survival was significantly associated with smoking ≥30 pack years (P = 0.03), LDH ≥202 (P = 0.04), and LMR < 2.90 (P < 0.01). In HPV-negative OPC patients, gender of male (P < 0.01), smoking ≥30 pack years (P < 0.01), LDH ≥202 (P < 0.01), and CRP/Alb ≥0.15 (P = 0.01) were significant predictors of poor survival.<bold>Conclusion: </bold>The present study revealed that high LDH levels predicted poor survival after definitive radiotherapy in both HPV-positive and HPV-negative OPC patients. High LDH levels were stronger poor prognostic factor than HPV status and TNM stage in this study. [ABSTRACT FROM AUTHOR]