A new prognostic tool for metastatic colorectal cancer patients receiving anti-angiogenic treatment, the PALM score: A single-center experience.

Abstract

e15575 Background: Even if anti-angiogenic agents are crucial for metastatic colorectal cancer (mCRC) patients (pts) treatment, to date, no validated prognostic biomarkers are available. We conducted at our Centre a retrospective research to identify a prognostic tool to be applied in clinical practice in this population. Methods: We retrospectively collected laboratory, radiological and clinical data of mCRC pts treated with anti-angiogenic agents at the Medical Oncology Unit of Cagliari University Hospital (2018- 02/2024) in order to identify a potential prognostic tool. Statistical analysis was performed with MedCalc (survival distribution: Kaplan-Meier; survival comparison: log-rank test; cut-off: ROC curves; differences among variables: Chi-square test). Results: Globally, 33 mCRC pts were evaluated in our study (19 male, 14 female; 13 RAS wild-type, 22 left-sided primary). 10 were treated with anti-angiogenic drugs in the 1st-line, 13 in the 2nd-line (bevacizumab and aflibercept) and 10 in 1st-2nd line. Median OS was 39.5 months (m) (95%CI:28.2-41.3), median Progression Free Survival (PFS) was 14.9 m (95%CI:9.5-18.5). Pts with lower platelet to lymphocyte ratio (P; ≤253; p < 0.0001, HR = 0,00000048; 95%CI 24.7-39.5 versus [vs] 95% CI 8.2-10.5), alkaline phosphatase (A; < 136 U/l; p = 0.0001, HR = 0.0001; 95%CI 12-39.5 vs 95% CI 8.2-10.5) and lactate dehydrogenasis (L; < 365 U/l; p < 0.0001, HR = 0.0000004; 95%CI 24.7-39.5 vs 95% CI 8.2-10.5) and higher monocyte count (M; > 0.3x103/μL; p = 0.0093, HR 0.01; 95%CI 26.5-39.5 vs 95%CI 8.2-24.7), showed a statistically improved OS. We created the “PALM score” and separated pts in two prognostic groups: good prognostic group (0 unfavorable variables: PALM = 0) and poor prognostic group (≥1 unfavorable variable, PALM = 1). OS was significantly improved in the good prognostic group (PALM = 0): 31.5 m (95%CI:24.7-39.5) vs 10.5 m (PALM = 1) (p = 0.0031, HR = 0.00006). Chi-square test revealed also a statistically significant correlation of upfront resection of primary tumor with the PALM score (73.9% of patients belonging to the PALM = 0 group had undergone surgery for primary tumor and all patients with resected primary belonged to the PALM = 0 group (p = 0.0352). Conclusions: Our research showed a promising prognostic role of easy-to-use PALM score tool in mCRC patients treated with anti-angiogenic drugs in a limited population at our center. Further prospective studies with larger sample size are needed to confirm our findings.