The causes and consequences for dose reduction in NSCLC IIIB patients, a retrospective single center clinical trial

Introduction: Dose reductions in chemotherapy occur frequently due to various reasons. The ubiquitous opinion is that dose reductions favor a negative outcome. However, there are only few studies that investigate this opinion in respect to lung cancer patients. The aim of this retrospective single-center study is to identify the most common predictors of dose reductions in NSCLC IIIB patients and to evaluate the effects thereof. Methods: The study includes 132 NSCLC IIIB patients treated between 2008 and 2017. Predictors of dose reductions were evaluated using uni- and multivariate methods and survival statistics were analyzed using Kaplan-Meier and logrank method. Results: 48% of the patients (n = 63) experienced dose reductions. Male gender (p = 0.029), age (p = 0.042), comorbidities (CCI) (p = 0.00) and palliative intent (p = 0.021) were identified as predictors of initial dose reductions. Initial dose reductions were independent of ECOG status and initial laboratory values. Dose reductions later in chemotherapy were linked to hematologic toxicities. 59% of patients with leukopenia and 33% of patients with bi- / pancytopenia had chemotherapeutic doses reduced consecutively. The was no sigificant difference in overall survival (OS) and progress-free survival (PFS) between patients with and without dose reduction. Patients with reduced doses had an OS of 18.86 (± 18.65) vs. 17.51 (± 16.61) months, p = 0.593 and a PFS of 15.03 (± 18.14) vs. 12.71 (± 17.60) months, p = 0.340. Conclusion: This study supports the view that hematotoxicities are considered the most serious side effects. Contrary to expectations, a reduction in chemotherapy dosage did not seem to be associated with a worse prognosis. Maybe a dose reduction can improve the side effect profile and compliance.