Impact of subsequent chemotherapy on the survival of elderly patients with extensive stage small cell lung cancer.

Background/aims: The prognosis of small cell lung cancer (SCLC) is still poor because of rapid recurrence, despite good response to initial chemotherapy. Additionally, patients' old ages and comorbidities are often obstacles that make it difficult to apply subsequent treatment after initial treatment. This retrospective study analyzed the correlation of post-progression survival (PPS) with overall survival (OS), and prognostic factors including comorbidities to figure out impact of subsequent chemotherapy on OS in elderly extensive disease SCLC.
Methods: We analyzed 101 patients of age 65 years or older who were recently diagnosed with extensive disease SCLC (ED-SCLC) in Korea University Medical Center between January 1995 and December 2015. The degree of comorbidity was scored using simplified comorbidity score (SCS). Correlation between PPS, progression-free survival (PFS) and OS was analyzed using a Pearson correlation coefficient. Cox proportional hazards regression was employed to examine the influence of clinical variables on survival.
Results: Median age of patients was 71 years old (range, 65 to 83). Median OS was 8.7 months (range, 0.3 to 42.7). PPS was a reliable factor on OS than PFS (R2 = 0.852, p < 0.001). Prognostic factors associated with improved survival were SCS < 9, administration > 4 cycles of first line chemotherapy and subsequent second line chemotherapy.
Conclusion: PPS was more correlated with OS than PFS in elderly patients with ED-SCLC. The most important prognostic factors for PPS and OS included SCS and second line chemotherapy. Patients receiving subsequent treatment had increased OS regardless of degree of comorbidity.