Effect of macrocytosis on erlotinib response in metastatic non-small cell lung cancer

Abstract

Background/Aim: Numerous studies have assessed the relationship between macrocytosis and responses to chemotherapeutic agents and TKIs such as sunitinib and imatinib. However, there is limited data in the literature regarding the prognostic or predictive value of macrocytosis in using erlotinib. If a relationship is detected, early response/resistance assessment can be performed before imaging time in the follow-up of treatments, and a more cost-effective, non-invasive method can be employed for response monitoring. This study aimed to elucidate the effect of macrocytosis on response rates in patients treated with erlotinib for non-small cell lung cancer. Methods: Seventy-five individuals diagnosed with non-small cell lung cancer (NSCLC) and admitted to our institution were enrolled in this retrospective cohort study. Baseline demographics, time of diagnosis, previous treatment, and the initiation or cessation of erlotinib were recorded. Data of patients with and without macrocytosis were analyzed. Stable disease, partial and complete response rates, and progressive disease response were evaluated separately as response rates. Progression-free survival between drug initiation and discontinuation due to progression was interpreted using Kaplan-Meier curves. Results: The distribution of the overall survival (OS) and progression-free survival (PFS) evaluations revealed that 84% (n=63) of the patients were deceased, and the progression rate was 94.7% (n=71). The median OS of the patients was 18 months, and the median PFS was 11 months. There was a statistically significant difference in overall survival in females, with a median OS of 25 months (95% CI 17–32 months) and a median OS of 13 months in males (95% CI 9–20 months) (P=0.008). PFS was 14.5 months (95% CI 11–21 months) in women and six months (95% CI 4–17 months) in men, and there was a statistically significant difference (P=0.02). A statistically significant difference was achieved between MCV values measured during diagnosis and the third month between age groups (P=0.044). Conclusion: The outcomes of this research suggest a statistically significant difference between the MCV values measured at the time of diagnosis and the third month regarding age groups. Both OS and PFS in women were statistically significantly higher than in men.