MET-8 Chemotherapy alone for brain metastases from small cell lung cancer -comparison with EGFR-TKI-

Background: Because of the invasive nature of small cell lung cancer (SCLC), the effectiveness of local therapy for brain metastases (BM) from SCLC had been limited. In this article, we retrospectively evaluated the efficacy of chemotherapy against non-treated BM from SCLC (SCLC-CHT) in compared with TKI for BM from EGFR-mutated NSCLC (EGFR-TKI).Materials and Methods: Un-treated 218 BM, including 58 SCLCs and 160 EGFR-mutated NSCLCs were enrolled. The primary endpoints were maximum response of BM and the duration of effect, and the secondary endpoints were times to the first and maximum responses, patterns of progression and overall survival after the diagnosis of BM.Results: The objective response rate (69%) and disease control rate (92%) of BM after SCLC-CHT were inferior to those after EGFR-TKI (85%, 97%), but were sufficiently satisfactory. Both the times to the first response (0.8m, 95% CI:0.6–0.9) and to the maximum effect after treatment(1.6m, 0.9–1.9) with SCLC-CHT were shorter than with EGFR-TKI (0.9m,0.9–1.0, P=0.011, and 2.4m, 1.9–2.8, P=0.004), but the duration of the response was conversely shorter with SCLC-CHT (5.1m, 4.2–5.6) than with EGFR-TKI (12.3m,9.2–15.1, P<0.0001). The dominant pattern of recurrence was local progression in the both groups. The risk of local progression after SCLC-CHT was higher than after EGFR-TKI (Fine-Gray HR:2.44, 1.56–3.83, P<0.0001), although the risk of new BM was not different between these two groups (0.94, 0.49–1.82, P=0.86). The risk of non-CNS death was higher after SCLC-CHT than after EGFR-TKI (1.8, 1.2–2.7, P=0.004), but the risk of CNS death was not different (0.92, 0.45–1.89,P=0.83).Conclusions: BM from SCLC well and quickly responded to CHT, but the duration of response was short. These responses of BM against CHT was comparable to that of extracranial disease. For the better control of BM and survival of patients, ingenuity to prolong the effect of CHT is required.