Changes of serum copper and zinc levels in patients with nasopharyngeal carcinoma by radiotherapy.

Serum copper levels (SCL) and serum zinc levels (SZL) were evaluated in 128 patients with nasopharyngeal carcinoma (NPC) of varying stages before, during, and after radiotherapy, and then compared with normal age-matched subjects. Among these patients, there were 119 undifferentiated squamous cell carcinoma, 5 differentiated squamous cell carcinoma, and 4 moderately differentiated squamous cell carcinoma, respectively. Before radiotherapy, SCLs were significantly higher in NPC patients than in normal subjects, but the difference of SZLs was not significant. The ratio of Cu/Zn also showed a significant difference between normal subjects and NPC patients preradiotherapy. Moreover, except stage II, patients with more advanced stages of the disease had more elevated Cu/Zn ratios. During and after the period of radiotherapy, the SCL decreased as compared with the level of preradiotherapy. The Cu/Zn ratio also decreased after radiotherapy but not significant. However, Cu/Zn ratio of expired patients at least 2 yr after radiotherapy did not show the significant decrease in contrast to the alive ones.