Longitudinal analysis of complete blood count parameters in advanced‐stage lung cancer patients

BACKGROUND: Metastatic lung cancer is a debilitating disease, but with the advances in immunotherapy, therapeutic options have vastly increased. Numerous complete blood count parameters (CBC) have been described as easily accessible biomarkers that might predict response to immunotherapy. However, to date, no comprehensive study has been performed on the longitudinal changes of these parameters during cancer progression. METHODS: The clinicopathological variables and CBC parameters of 986 advanced stage lung cancer patients were retrospectively analyzed. Blood tests were performed as part of the routine checkup and the results were recorded at the time of the diagnosis of the primary tumor, the diagnosis of brain or bone metastases, and also during the last available follow‐up. RESULTS: In the experimental subcohort, 352 and 466 patients were diagnosed with brain and bone metastases, respectively. The control group consisted of 168 patients without clinically detectable or other distant organ metastases. In our longitudinal analyses, we found significantly decreasing absolute lymphocyte count (ALC: P < 0.001), and significantly increasing absolute neutrophil count (ANC: P < 0.001) levels in all patient subgroups, irrespective of histopathological type and metastatic site. Interestingly, patients with brain metastases had significantly descending‐ascending platelet count (PLT) trendlines (P < 0.001), while the bone metastatic subgroup exhibited significantly ascending‐descending trendlines (P = 0.043). CONCLUSIONS: Significantly decreasing ALC, significantly increasing ANC and fluctuating PLT levels may be found in brain and bone metastatic lung cancer patients during disease progression. Our findings might contribute to improve personalized healthcare in this devastating malignancy. KEY POINTS: SIGNIFICANT FINDINGS OF THE STUDY: Significantly decreasing ALC, and significantly increasing ANC levels can be found in advanced‐stage lung cancer patients during disease progression. Patients with brain metastases have descending‐ascending PLT trendlines, while patients with bone metastases exhibit ascending‐descending trendlines during disease progression. WHAT THIS STUDY ADDS: The descending values for ALC, and the ascending mean values for PLT and ANC, might be suggestive of poor response to second‐ or third‐line immunotherapy in advanced‐stage lung cancer patients. The current study might help to improve patient selection and treatment strategies for brain and/or bone metastatic lung cancer patients.