Predictive value of 8-hydroxy-2′-deoxyguanosine and 8-nitroguanine production in radiation-induced skin damage after postoperative breast cancer radiotherapy

Aim: During radiation treatment, reactive oxygen species (ROS) and nitrogen species (RNS) are produced and, by extension, DNA adducts known as 8-hydroxy-2′-deoxyguanosine (8-OHdG) and 8-nitroguanine (8-NG), respectively. However, one of the most common side effects induced by radiotherapy is skin toxicity, which affects patients’ quality of life. In the present study, we aimed to investigate the potential predictive value of 8-OHdG and 8-NG by exploring the correlations between the alterations in the concentration levels of the two lesions and radiation-induced tissue injury upon exposure to external beam radiotherapy. Methods: For the purpose of this work, we collected blood serum samples from 33 breast cancer patients who received adjuvant radiotherapy. To conduct statistical analysis, we used: (1) linear adjustment to correlate the percent changes of 8-OHdG and 8-NG with the degree of toxicity; and (2) polynomial adaptation and exponential fitting to correlate the percent changes of 8-OHdG and 8-NG with the correlation coefficient r for the development of radiation dermatitis, respectively. Results: According to our findings, there is a statistically significant correlation between the alterations in the 8-OHdG and 8-NG levels and skin grade toxicity across time and varying radiation doses (p < 0.05). Conclusions: Both DNA lesions seem to possess a promising predictive role in radiation dermatitis, while the severity and exact grade of radiation-induced skin toxicity can be determined.