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O21 - SCLC II (ID 119)
- Event: WCLC 2013
- Type: Oral Abstract Session
- Track: Medical Oncology
- Presentations: 1
O21.07 - A new prognostic model for relapsed/refractory extensive stage small cell lung cancer (ES-SCLC) derived from prospective SWOG trials: implications for study design (ID 966)
16:15 - 17:45 | Author(s): J. Allen
ES-SCLC patients (pts) with progressive disease (PD) following plat-based chemo have traditionally been categorized as plat-sensitive (PD >/= 90 days from last plat dose) or refractory (PD < 90 days). Plat-sensitivity status has previously been strongly associated with response and survival in the 2[nd]/3[rd] line treatment setting. However, in a recent pooled analysis of SWOG trials in 2[nd]/3[rd] line SCLC pts, plat-sensitivity status was found to no longer be a significant independent variable for survival (Lara, ASCO 2013). We subsequently developed a new SCLC prognostic model for overall survival (OS) for potential clinical trial and bedside application.
Updated data from recent SWOG trials in 2nd and/or 3rd line ES-SCLC (S0802: topotecan + aflibercept: S0435: sorafenib; and S0327: PS-341) were pooled. Accrual goals were specified for sensitive and refractory in each trial. Hazard ratios (HRs) for OS were calculated using Cox Proportional Hazard (PH) models [unadjusted and adjusted]. To investigate a predictive model for OS, recursive partitioning was performed using the likelihood tree model of LeBlanc and Crowley. The minimum node size was set at 20.
Of 329 pts, 151 were classified as sensitive, 178 refractory; median age = 63 years; males = 52%; Performance Status (PS) 1 = 67%; weight loss >5% = 28%; > 2 prior chemo = 16%; and elevated LDH = 43%. HRs from unadjusted Cox models for OS for refractory vs. sensitive were 1.0 (95% CI 0.81-1.25, p=0.98) and 1.24 (95% CI 0.99, 1.57; p=0.06). Cox PH models adjusted for baseline prognostic factors showed that plat-sensitivity status was not significantly associated with OS. Elevated LDH was significantly associated with PFS while LDH, PS, weight loss, and male sex were independently associated with OS. Clinically relevant prognostic risk groups (High, Intermediate, and Low) were identified by recursive partitioning analysis, as shown below (MST= median survival time). High Risk (MST = 2 months: Elevated LDH And > 5% Weight Loss Or PS >0) Intermediate Risk (MST = 5 months: Elevated LDH but not High Risk Or Male) Low Risk (MST=8 months: Normal LDH And Female)
In this large database analysis, clinically relevant prognostic risk groups were identified, categorized as low, intermediate, and high risk, with differential survival outcomes observed for each group. Validation of these risk groups in an independent SCLC dataset is warranted. If validated, these risk groups will have important implications for individualized patient counseling in clinic and stratification of patients in prospective trials in the second and third line setting.