Associations of D-dimer and lactate dehydrogenase with RECIST 1.1-defined disease status in patients with solid tumors: an exploratory single-center retrospective study

To examine the associations of D-dimer and lactate dehydrogenase (LDH) with progressive disease (PD) at the available clinical assessment and to describe the apparent discrimination of an exploratory two-biomarker model in patients with solid tumors. This single-center retrospective cohort study included 285 patients with solid tumors treated between January and November 2025. Patients were classified as having disease control (DC) or progressive disease (PD) according to RECIST 1.1 at the available clinical assessment. Continuous D-dimer and LDH measurements were examined in ROC analyses, and sample-specific cut-offs were derived using the Youden index. Both biomarkers were entered as continuous variables into an adjusted logistic regression model. Apparent discrimination of an exploratory two-biomarker model was assessed in the same cohort used to fit the model. Among 285 patients, 224 had DC and 61 had PD. In the adjusted model, each 100-ng/mL increase in D-dimer (adjusted odds ratio [aOR], 1.030; 95% confidence interval [CI], 1.009–1.051) and each 100-U/L increase in LDH (aOR, 1.391; 95% CI, 1.003–1.929) were associated with PD. Baseline metastasis was also associated with PD (aOR, 4.406; 95% CI, 1.281–15.147). The uncorrected apparent AUCs were 0.770 (95% CI, 0.702–0.839) for D-dimer, 0.730 (95% CI, 0.651–0.812) for LDH, and 0.790 (95% CI, 0.724–0.855) for the two-biomarker model, all estimated within the same cohort. Higher D-dimer and LDH levels measured during treatment were associated with PD in this heterogeneous cohort. The apparent discrimination and sample-derived cut-offs should be interpreted cautiously, as estimates obtained within the same cohort may be optimistic. These preliminary, hypothesis-generating findings require independent prospective validation to determine whether the biomarkers offer added value in clinical assessment.