The prognostic value of the De Ritis ratio on progression free survival in patients with NET undergoing [¹⁷⁷Lu]Lu-DOTATOC-PRRT: A retrospective analysis

Ziel/Aim The De Ritis ratio (AST/ALT ratio) has demonstrated prognostic value in various cancer entities. We evaluated the prognostic capability of De Ritis ratio in patients with metastatic neuroendocrine tumors (NET) undergoing peptide receptor radionuclide therapy (PRRT).

Methodik/Methods Unicentric, retrospective analysis of 125 patients with NET (female: n = 46; male: n = 79; median age: 66 years) undergoing PRRT with an average dose of 7.45 GBq [¹⁷⁷Lu]Lu-DOTATOC per cycle (median: 3; range: 1 - 6 cycles). The prognostic value regarding PFS was analysed with univariable Cox regression for clinical variables (age, sex, ECOG, primary tumor location, metastatic pattern, functionality, Hedinger syndrome) and laboratory parameters (De Ritis ratio, Chromogranin A [CgA]). De Ritis ratio was binarized using an optimized cut-off (>0.927) based on the log-rank test. Cut-off for CgA was twice the upper normal limit (2xULN; 204 µg/l). Multivariable Cox analysis included all variables with p≤0.1 in univariable Cox. Based on multivariable Cox, high De Ritis ratio and CgA were combined as a prognostic score. Prognostic accuracy was determined with Harrell’s C index and likelihood ratio test.

Ergebnisse/Results Progression, relapse or death after PRRT was observed in 102/125 patients. Median PFS was 15.8 months. Pancreatic or pulmonary origin, high De Ritis and high CgA significantly predicted shorter PFS in univariable Cox. In multivariable Cox regression, only De Ritis ratio >0.927 (HR: 1.70; p = 0.047) and CgA >2xULN (HR: 2.05; p = 0.005) remained independent predictors of shorter PFS. PFS in patients with both risk factors was 12.4 months compared to 20.4 or 34 months with one or none of the risk factors. Adding De Ritis ratio >0.927 to the multivariable Cox model (age, ECOG, primary origin, CgA) significantly improved prognostic accuracy (Harrell’s C = 0.65; p < 0.001).

Schlussfolgerungen/Conclusions The De Ritis ratio is simple to obtain in clinical routine and provided independent prognostic value for PFS in patients with NET undergoing PRRT.

Publication History

Article published online:
08 April 2021