Determinants of Myelosuppression in the Treatment of Non‐small Cell Lung Cancer with Cisplatin‐containing Chemotherapy

Data on 16 potential risk factors for myelosuppression were assessed in 134 patients who received either vindesine and cisplatin (VP) or mitomycin C, vindesine and cisplatin (MVP) for inoperable stage III or IV non‐small cell lung cancer in a randomized trial. Determinant factors for myelosuppression were evaluated by using univariate analysis and the logistic regression model. Recursive partitioning and amalgamation (RPA) was also used to define patient subgroups frequently suffering from severe bone marrow toxicity. Overall, 33 (25%) of 134 patients experienced at least one episode of grade 4 leukopenia. In univariate analysis, age, body surface area, serum creatinine, and pretreatment hemoglobin concentration were associated with severe leukopenia. A multivariate analysis using the logistic regression method showed that only raised creatinine level was an independent predictor for grade 4 leukopenia (P=0.049). The RPA model generated three distinct subgroups based on age, body surface area and regimen. The three subgroups were distinguished by the frequency of severe (grade 4) leukopenia (50%, 25%, and 2.4%, respectively) (P<0.001). Grade 4 leukopenia occurred more frequently in patients in class 3 (age ≥65 years and treatment with MVP). The RPA model was useful in identifying the risk factors for myelosuppression induced by cisplatin‐based chemotherapy, and in defining patient subgroups with elevated risk of toxicity.