Outcomes of small-cell lung cancer patients treated with second-line chemotherapy: a multi-institutional retrospective analysis

Background: Patients with small-cell lung cancer (SCLC) that progress after first-line chemotherapy have a poor prognosis and the evidence of a benefit from second-line (SL) chemotherapy is limited. Patients relapsing or progressing more than 90 days after completion of first-line treatment are considered platinum sensitive and may be rechallenged with platinum-based chemotherapy. Topotecan is approved as SL treatment independent of time to progression. This retrospective analysis evaluates the clinical outcomes of SCLC patients who received SL chemotherapy after platinum-etoposide chemotherapy.

Patients and methods: We retrospectively reviewed 161 patients who received SL chemotherapy for SCLC. Patients were divided into four subgroups by type of SL treatment: (1) platinum-based rechallenge; (2) anthracycline-based regimens; (3) topotecan; (4) other single agents. The endpoints were overall survival (OS), progression-free survival (PFS) and response rate (RR). Survival curves were plotted using the Kaplan-Meier method. The Cox proportional hazard model was used for multivariate analysis to investigate factors influencing survival.

Results: The median age was 63. There were 125 males and 36 females. Eastern Cooperative Oncology Group performance status (ECOG-PS) was 0, 1 and 2 in 12.5%, 62.5% and 25% of patients, respectively. Platinum sensitive/platinum resistant/platinum refractory/unknown=121/29/3/8 patients. Median time to SL chemotherapy was 6.9 months. The median PFS from starting second-line treatment was 4.3 months and median OS was 5.8 months. The overall RR was 22.9%. There was a trend toward higher RR (34.5% vs 17.5%, p for trend: 0.06) and OS (9.2 months vs 5.8 months, p=0.08) for patients with sensitive disease who were rechallenged with platinum-based chemotherapy. A multivariate analysis that adjusted for the time to SL treatment showed that a platinum-containing regimen achieves better RR, PFS and OS independently of the time to SL chemotherapy and that response to first-line treatment and PS at SL are the only independent prognostic factors.

Conclusions: The outcome for second-line therapy for SCLC was poor and benefit appeared to be limited to those patients with good PS and rechallenged with platinum-based chemotherapy. Platinum-based rechallenge should be considered as a standard comparator in future randomized controlled trials of SL chemotherapy.