Relapsed small cell lung cancer: treatment options and latest developments

According to recent analyses, there was a modest yet significant improvement in median survival time and 5-year survival rate of limited stage small cell lung cancer (SCLC) in North America, Europe, Japan and other countries over the last 30 years. The median survival time of limited stage SCLC is 15-20 months and 5-year survival rate is 15% or less. In terms of extensive stage SCLC, a median survival time of 9.4-12.8 months and 2-year survival of 5.2-19.5% are still disappointing. Despite being highly sensitive to first-line chemotherapy and radiotherapy treatments, most patients with SCLC experience relapse within 2 years and die from systemic metastasis. While several clinical trials of cytotoxic chemotherapies and molecular targeting agents have been investigated in the treatment of relapsed SCLC, none showed a significant clinical activity to be able to exceed topotecan as second-line chemotherapy. There are problematic issues to address for relapsed SCLC, such as standardizing the treatment for third-line chemotherapy. Topotecan alone was the first approved therapy for second-line treatment for relapsed SCLC. Amrubicin is a promising drug and a variety of trials evaluating its efficacy have been carried out. Amrubicin has shown superiority to topotecan in a Japanese population, but was not superior in a study of western patients. There are some controversial issues for relapsed SCLC, such as treatment for older patients, third-line chemotherapy and efficacy of molecular targeting therapy. This article reviews current standard treatment, recent clinical trials and other topics on relapsed SCLC.