1610P - A new updated prognostic index for patients with brain metastases (BM) treated with palliative whole brain radiotherapy (WBRT) in the era of precision oncology: METASNCore project

Background

Palliative WBRT is the main treatment for multiple brain metastases. Recent studies report no benefit in survival after WBRT compared to palliative supportive care in patients (pts) with poor prognosis. The purpose of this study is to develop and statistically validate a prognostic score in palliative pts with BM who undergo WBRT and compare it with previous scores.

Methods

239 pts with BM who received palliative WBRT between 2013-2022 in our center were analyzed retrospectively. The score was designed according to the value of the β coefficient of each variable with statistical significance in the multivariate model. Once the score was established, a comparison was performed according to Kaplan-Meier and was analyzed by log-rank test. We also studied the concordance between MetaSNCore and the RPA scale (gold standard). Finally, METASNcore was validated in a different sample of 100 patients.

Results

149 pts (62.3%) were male and median (m) age was 60 years. 139 (58,2%) were lung cancer and 35 (14,6%) breast cancer. All patients received 30Gys in 10 sessions. 37 pts (15,5%) had a specific target mutation and mOS was 3,74 months. Each point in the score is associated with a HR 1.243 (CI 95% 1.164 - 1.329) (p<0.001) (Table). 144 pts were in group “good prognosis” (up to 7 points) with mOS 4.9ms (CI 95% 3.94 - 5.8); 92 in group “bad prognosis” (above 7) with mOS 2.73ms (CI 95% 1.93 - 3.5) (p<0.001). After RPA concordance analysis, METASNcore had a specificity of 88.5% (CI 95% 82.9-94.2) and a sensitivity of 68.4% (CI 95% 59.9-77). We also found statistically significant differences in the validation sample (mOS 4.6ms (CI 95% 3 - 6.2) versus mOS 1.45ms (CI 95% 1.16 - 1.74)) (p<0,05).

Table: 1610P

Conclusions

The variables in our cohort included in METASNCore are independently associated with OS and could be useful for selecting palliative patients who are candidates for WBRT. Further studies are needed to corroborate our findings.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Maimonides Biomedical Research Institute of Cordoba (IMIBIC).

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.