3438 - High-biologically effective dose radiotherapy improve the survival of small cell lung cancer patients with brain metastases: a propensity-matching analysis

Background

To compare the effects of high biologically effective dose (BED) and low BED radiotherapy for small cell lung cancer (SCLC) with brain metastases (BMs), and identify the prognostic factors of survival.

Methods

A total of 250 consecutive SCLC (stage II-IV) with BMs patients in our institution were retrospectively analyzed, from January 1998 to June 2018. Preliminary screening of the prognostic factors was accomplished by Kaplan-Meier univariate analysis. Baseline covariates were balanced by a propensity score model. And survival curves between the two groups were compared by the log-rank test. The Cox regression model was used to analyze factors associated with prognosis.

Results

The Cutoff Finder program exported an optimal BED cutoff value of 47 for all patients. The high-BED (>47 Gy) group had a significantly better OS than low-BED (≤47 Gy) group (median OS: 17.5 vs. 9.5, P < 0.001). Multivariate analysis found that BED (P < 0.001), smoking (P = 0.017), ECOG score (P = 0.047) and age (P = 0.004) were independently prognostic factors affecting OS. And after 1:2 propensity score matching, 163 patients were divided into the high-BED group (n = 57) and the low-BED group (n = 106). In the matched cohort, OS was significantly higher in the high-BED group than low-BED group (P < 0.001).

Conclusions

BED, smoking, ECOG score, age were observed to affect the OS of SCLC patients with BMs. High BED radiotherapy (>47 Gy) might improve long-term survival.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Qingyang, Zhuang.

Funding

The Fujian Province Natural Science Foundation (2017J01260), Joint Funds for the Innovation of Science and Technology, Fujian province (2017Y9074), and the Peking University Cancer Hospital & Institute, Key Laboratory of Carcinogenesis and Translational Research, Ministry of Education/Beijing (2017 Open Project-9).

Disclosure

All authors have declared no conflicts of interest.