Modification of the novel RANO clinical risk score for low- and middle-income countries without access to MGMT methylation testing.

Abstract

2052 Background: The RANO Resect Group developed a new risk score using simple variables, including age, Karnofsky performance scale (KPS), RANO resection class (RRC), and MGMT methylation (MGMTm), for patients with IDH-wildtype glioblastoma (GBM). Although this score is easy to apply and demonstrates high prognostic accuracy, routine testing for MGMTm remains inaccessible in many low- and middle-income countries. In this study, we aimed to modify the RANO risk score by excluding MGMTm. Methods: This is a single-center, retrospective analysis of IDH-wildtype GBM patients. We applied the same scoring system established by the RANO Resect Group, excluding MGMTm. The point (p) allocations were as follows: RRC1 = 0p, RRC2 = 1p, RRC3 = 2p, RRC4 = 5p; KPS > 80 = 0p, KPS < 80 = 3p; age < 65 = 0p, and age > 65 = 1p (age was not scored if RRC = 1p). The relationship between overall survival (OS) and the variables (age, KPS, and RRC) was evaluated using univariate and multivariate Cox regression analyses. Three risk classes were defined as numerical scores derived through ROC analysis. The primary endpoint was overall survival, and the secondary endpoint was progression-free survival (PFS). Results: A total of 119 patients were included in the study. Of these, 100 patients received chemoradiotherapy with temozolomide followed by adjuvant temozolomide (CRT-TMZ), while 13 received CRT only, 1 patient received temozolomide only, and 1 received radiotherapy only. Four patients were unable to undergo any treatment. RRC, age, and KPS classifications were all significantly associated with overall survival in both univariate and multivariate analyses (p < 0.001).Based on ROC curve analysis, three risk classes were identified: low risk (0–1 points, n:47, 39.5 %), intermediate risk (2–3 points, n:27, 22.7 %), and high risk (≥4 points, n:45, 37.8 %). The median OS was 35.5 months (95% CI: 21.1–50) for the low-risk group, 16 months (95% CI: 9.9–22.1) for the intermediate-risk group, and 5 months (95% CI: 3.8–6.1) for the high-risk group (p < 0.001). Similarly, the median PFS was 16.3 months (95% CI: 12.3–20.2) for the low-risk group, 9.9 months (95% CI: 7.2–12.6) for the intermediate-risk group, and 4.1 months (95% CI: 3.4–4.8) for the high-risk group (p < 0.001). Conclusions: The modification of the novel RANO clinical risk score by omitting MGMTm remains highly prognostic for patients with IDH-wildtype GBM. Since it relies on very basic parameters and is easy to use, the modified RANO score can serve as a practical tool in countries where MGMTm testing is inaccessible.