A retrospective study of amrubicin monotherapy for the treatment of relapsed small cell lung cancer in elderly patients

Amrubicin is one of the most active chemotherapeutic drugs for small cell lung cancer (SCLC). Previous studies reported its effectiveness and severe hematological toxicity. However, the efficacy of amrubicin monotherapy in elderly patients with SCLC has not been described. The objective of this study was to investigate the feasibility of amrubicin monotherapy in elderly patients and its efficacy for relapsed SCLC. A retrospective cohort study design was used. We retrospectively evaluated the clinical effects and adverse events of amrubicin treatment in elderly (70 years) SCLC patients with relapsed SCLC. Between November 2003 and September 2015, 86 patients (aged 70 years) received amrubicin monotherapy for relapsed SCLC at four institutions. There were 42 cases of sensitive relapse (S) and 44 of refractory relapse (R). S cases with median age of 75 years (range 70-85 years) and R cases with median age of 74 years (range 70-84 years) were included in our analysis. The median number of treatment cycles was three (range 1-9), and the response rate was 33.7% (40.5% in the S and 27.2% in the R cases). Median progression-free survival time was 4.0 months in the S and 2.7 months in the R patients (p = 0.013). Median survival time from the start of amrubicin therapy was 7.6 months in the S and 5.5 months in the R cases (p = 0.26). The frequencies of grade 3 hematological toxicities were as follows: leukopenia, 60.4%; neutropenia, 74.4%; anemia, 11.6%; thrombocytopenia, 16.2%; and febrile neutropenia, 17.4%. Treatment-related death was observed in one patient. Although hematological toxicities, particularly neutropenia, were severe, amrubicin showed favorable efficacy, not only in the S but also in the R cases, as shown in previous studies. Amrubicin could be a preferable standard treatment in elderly patients with relapsed SCLC. These results warrant further evaluation of amrubicin in elderly patients with relapsed SCLC by a prospective trial.