Correlation between DNA repair capacity in lymphocytes and acute side effects to skin during radiotherapy in nasopharyngeal cancer patients.
OBJECTIVE
Repair of radiation-induced DNA damage plays a critical role for both the susceptibility of patients to side effects after radiotherapy and their subsequent cancer risk. The study objective was to evaluate whether DNA repair data determined in vitro are correlated with the occurrence of acute side effects during radiotherapy.


METHODS
Nasopharyngeal cancer patients receiving radiation therapy were recruited in a prospective epidemiologic study. As an indicator for clinical radiosensitivity, adverse reactions of the skin were recorded. Cryopreserved lymphocytes from 100 study participants were gamma-irradiated with 5 Gy in vitro and analyzed using the alkaline comet assay. Reproducibility of the assay was determined by repeated analysis (n = 22) of cells from a healthy donor. A coefficient of variation of 0.24 was calculated.


RESULTS
The various parameters determined to characterize the individual DNA repair capacity showed large differences between patients. Twenty-one patients were identified with considerably enhanced DNA damage induction, and 19 patients exhibited severely reduced DNA repair capacity after 15 and 30 minutes. Eight patients were considered as clinically radiosensitive, indicated by moist desquamation of the skin after a total radiation dose of 70 Gy.


CONCLUSIONS
Using the alkaline comet assay as described here, nasopharyngeal cancer patients were identified showing abnormal cellular radiation effects, but this repair deficiency corresponded only at a very limited extent to the acute radiation sensitivity of the skin.
Wang
Wei-dong
WD
Department of Oncology, Xinqiao Hospital, Chongqing, PR China.
Chen
Zheng-tang
ZT
Li
De-zhi
DZ
Cao
Zheng-huai
ZH
Sun
Shi-liang
SL
Pu
Ping
P
Chen
Xiao-pin
XP
D000328:Adult; D000368:Aged; D020552:Comet Assay; D004249:DNA Damage; D004260:DNA Repair; D016021:Epidemiologic Studies; D005260:Female; D006801:Humans; D008214:Lymphocytes / Q000502:physiology; D008297:Male; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D011446:Prospective Studies; D011832:Radiation Injuries / Q000235:genetics* / Q000503:physiopathology*; D012720:Severity of Illness Index; D012867:Skin / Q000473:pathology* / Q000528:radiation effects*