Pretreatment Albumin-to-Alkaline Phosphatase Ratio Is a Prognostic Marker in Lung Cancer Patients: A Registry-Based Study of 7077 Lung Cancer Patients

SIMPLE SUMMARY: Since the albumin-to-alkaline phosphatase ratio (AAPR) has shown promising prognostic prediction in cancer patients, the prognostic value of the AAPR was evaluated in a large cohort of 7077 lung cancer patients. We combined patient data from the Danish Lung Cancer Registry and the clinical laboratory information system (LABKA) and showed that a low AAPR was independently associated with an inferior median overall survival in non-small cell lung cancer patients and small cell lung cancer patients. Furthermore, data indicated a level-dependent correlation between the AAPR and survival and that the AAPR added additional prognostic value to the already well-established prognostic markers in lung cancer. Therefore, if our findings are validated in the future, the AAPR should be incorporated as a factor in the general prognostication of lung cancer patients. ABSTRACT: The albumin-to-alkaline phosphatase ratio (AAPR) is a novel promising prognostic marker in cancer patients. However, the evidence for its significance in lung cancer is scarce. Therefore, we assessed the prognostic value of the AAPR in a large cohort of lung cancer patients. Data on lung cancer patients diagnosed from January 2009 to June 2018 were extracted from the Danish Lung Cancer Registry and combined with data on the pretreatment serum AAPR level extracted from the clinical laboratory information system (LABKA). AAPR tertiles were applied as cutoffs. Cox proportional hazard models assessed the prognostic value of the AAPR. In total, 5978 non-small cell lung cancer (NSCLC) patients and 1099 small cell lung cancer (SCLC) patients were included. Decreasing AAPR level was significantly associated with declining median overall survival (OS) in NSCLC patients (medium vs. low AAPR, adjusted HR = 0.73 (95% confidence interval (CI) 0.68–0.79); high vs. low AAPR, adjusted HR = 0.68 (95% CI 0.62–0.73)) and in SCLC patients (medium vs. low AAPR, adjusted HR = 0.62 (95% CI 0.52–0.74); high vs. low, adjusted HR = 0.59 (95% CI 0.50–0.70)). In conclusion, the AAPR was an independent prognostic factor in NSCLC and SCLC patients. The correlation seems to be level dependent, with reducing survival found to be associated with decreasing AAPR level.