<![CDATA[Background: Tumor hypoxia promotes lung cancer progression and treatment resistance. HIF-1α regulates cellular adaptation to hypoxia and may serve as a biomarker of treatment response, although its association with systemic oxygenation remains unclear. Objective: This study evaluated changes in HIF-1α, oxygenation parameters, and hemoglobin levels and examined their associations with chemotherapy response in lung cancer patients. Methods: A prospective cohort study was conducted involving 33 lung cancer patients undergoing chemotherapy at Dr. Saiful Anwar Regional General Hospital. HIF-1α, blood oxygenation parameters (PaO₂ and SaO₂), and hemoglobin were measured before and after chemotherapy. Treatment response was assessed using RECIST 1.1. Data were analyzed using SPSS 26.0 with Shapiro–Wilk, unpaired t-test/Mann–Whitney, and Spearman correlation tests. Results: Significant differences were observed in HIF-1α levels, oxygen saturation, and partial pressure of oxygen between progressive and non-progressive response groups after chemotherapy (p = 0.04; p = 0.006; p = 0.008). HIF-1α levels were significantly correlated with pre-chemotherapy hemoglobin levels (r = 0.46; p = 0.007). Pre-chemotherapy HIF-1α levels were also correlated with post-chemotherapy oxygen saturation in the progressive group (r = 0.881; p = 0.004). Post-chemotherapy HIF-1α levels showed a significant negative correlation with thoracic CT evaluation based on RECIST 1.1 after the third chemotherapy series (r = –0.385; p = 0.027). Conclusion: Evaluation of chemotherapy response in lung cancer should consider HIF-1α levels and oxygenation status. Post-chemotherapy HIF-1α, PaO₂, and SaO₂ were associated with disease progression, whereas hemoglobin was not a reliable indicator of treatment response.]]>
