Applicability of the comet assay in evaluation of DNA damage in healthcare providers’ working with antineoplastic drugs: a systematic review and meta-analysis

Unintended occupational exposure to antineoplastic drugs (ANDs) may occur in medical
personnel. Some ANDs are known human carcinogens and exposure can be monitored by genotoxic
biomarkers.
Objective: To evaluate the obstacles to obtaining conclusive results from a comet assay test to determine DNA
damage among AND exposed healthcare workers.
Methods: We systematically reviewed studies that used alkaline comet assay to determine the magnitude and
signifcance of DNA damage among health care workers with potential AND exposure. Fifteen studies were eligible
for review and 14 studies were used in the meta-analysis.
Results: Under random effect assumption, the estimated standardized mean difference (SMD) in the DNA
damage of health care workers was 1.93 (95% CI: 1.15–2.71, p < 0.0001). The resulting SMD was reduced to
1.756 (95% CI: 0.992–2.52, p < 0.0001) when the analysis only included nurses. In subgroup analyses based
on gender and smoking, heterogeneity was observed. Only for studies reporting comet moment, I2 test results,
as a measure of heterogeneity, dropped to zero. Heterogeneity analysis showed that date of study publication
was a possible source of heterogeneity (B = −0.14; p < 0.0001).
Conclusions: A mixture of personal parameters, comet assay methodological variables, and exposure
characteristics may be responsible for heterogenic data from comet assay studies and interfere with obtaining
conclusive results. Lack of quantitative environmental exposure measures and variation in comet assay protocols
across studies are important obstacles in generalization of results.