Small cell lung cancer (SCLC) is an aggressive disease with 5-year survival rate of 31% in stage I and 2% in stage IV. Current general practice is to treat SCLC patients as soon as possible after diagnosis given its rapid doubling time and high growth fraction. There is no good evidence for appropriate timing of treatment from diagnosis (TTD) for SCLC. This study evaluates TTD in SCLC and its effect on survival.
SCLC patients were abstracted from 2012 to 2015 Kentucky Cancer Registry as a part of Lung Cancer Education Awareness Detection Survival (LEADS) Collaborative and included 2992 patients. Data collected included age at diagnosis, stage, gender, race, insurance and treatment. Factors associated with TTD were identified with logistic regression analyses adjusted for age, gender, race, stage, and insurance status. Derived odds ratios (OR) and 95% confidence intervals (CIs) are reported. Survival of patients by TTD (≤4 weeks vs > 4 weeks) was assessed with Cox proportional hazards models, adjusted for age, gender, race, stage, and insurance status. Hazard ratios (HR) and 95% CIs were reported.
Among the 2992 SCLC patients, 67% were stage 4 and 27% were stage 3 diseases. 2371(79%) of SCLC patients were treated with one or more treatment modalities and 621(21%) received no treatment after diagnosis. Among treated patients 93% patient received chemotherapy ± radiation with mean time of treatment from diagnosis of 18 days. Most patients (80%) have TTD of ≤ 4 weeks with 33% treated within 1 week, 20% 1-2 weeks, and 27% 2-4 weeks from diagnosis. Delay in treatment (TTD >4 weeks) was less in stage III and IV disease (OR: 0.34 & 0.27 respectively, p < 0.01) but not significantly associated with age, race, gender and insurance. One and two-year survival of patients with TTD ≤4weeks was significantly worse when compared to > 4 weeks (HR = 1.43, 95% CI 1.2-1.6, p < 0.01; HR = 1.45, 95% CI 1.3-1.6, p < 0.01 respectively). This is true even when stratified by stage.
These results show a trend towards poor survival with early treatment in SCLC which refutes current belief of better survival with early treatment. It is unclear why this trend exists, and further studies are needed to better clarify appropriate timing of treatment from diagnosis in SCLC and who will benefit from early vs late treatment.
Clinical trial identification
Legal entity responsible for the study
Brown Cancer Center, University of Louisville.
LEADS Collaborative supported by Bristol-Myers Squibb foundation.
All authors have declared no conflicts of interest.