High DNA damage levels to predict hematologic toxicity in testicular germ cell tumor (TGCT) patients treated with first-line chemotherapy.

Abstract

e16055 Background: TGCTs are an excellent example of chemosensitive disease. However, cisplatin-based chemotherapy has significant side effects, including myelosuppression. Previously, we found endogenous DNA damage level in peripheral blood mononuclear cells (PBMCs) to be an independent prognostic marker. We tested the hypothesis that patients with high endogenous DNA damage levels in PBMCs have an increased risk of developing hematologic toxicity. Methods: 120 chemotherapy-naïve patients with TGCTs treated in the National Cancer Institute and the St. Elisabeth Cancer Institute in Bratislava, Slovakia, from 2012 to 2018 were enrolled. All patients received platinum-based chemotherapy with G-CSF support. On the day of starting treatment, we measured the endogenous DNA damage levels in PBMCs using the Comet assay. We used a cut-off level of 5.25, a value previously found to stratify patients based on their prognosis. We monitored hematologic toxicity during the 1st cycle of chemotherapy. The mean and SEM were calculated for all variables. Results: Patients with high DNA damage levels ( > 5.25) had more significant hematologic toxicity with significantly lower nadir white blood cell count (6.0±1.1×109/L vs 9.8±1.0×109/L p = 0.001), absolute neutrophil count (4.1±1.0×109/L vs 7.0±0.9×109/L p = 0.013) and absolute lymphocyte count (ALC, 1.1±0.1×109/L vs 1.5±0.1×109/L p < 0.001). ALCs on day 0 (1.5±0.1×109/L vs 1.8±0.1×109/L p = 0.005) and day 22 (2.0±0.1×109/L vs 2.4±0.1×109/L p = 0.046) were also significantly lower in patients with high DNA damage levels. There were no significant differences in hemoglobin levels or platelet counts between the two groups. Neutrophil to lymphocyte ratio and systemic immune-inflammation index were lower at nadir in patients with high DNA damage levels, however, these differences were not statistically significant (p = 0.08 and p = 0.10, respectively). Conclusions: This study shows that higher endogenous DNA damage levels correlate with an increased risk of hematologic toxicity. The Comet assay data can be used to select patients for closer monitoring due to a higher risk of acute chemotherapy-related complications.