Cytogenetic damage of radiotherapy in long-term head and neck cancer survivors

Abstract

Purpose: To evaluate cytogenetic damage of radiotherapy (RT) and chemoradiotherapy (CRT) in long-term head and neck cancer survivors.Materials and methods: This study included 20 patients treated with RT (10 patients) or CRT (10 patients) for head and neck cancer. Nine healthy volunteers were included as control subjects. Cytochalasin B-blocked micronucleus (CBMN) assay was used to evaluate cytogenetic damage. To evaluate micronucleus (MN) by CBMN, the venous blood samples were drawn median 68 months (range 60–239 months) after the completion of treatment (RT or CRT) for head and neck cancer.Results: Nuclear division index (NDI) and number of MN in mononuclear and binuclear lymphocytes were significantly higher in patients with head and neck cancer than in control subjects [1.19 (1.08–1.47) vs. 1.07 (1.04–1.14), p < 0.001; 11.0 (2.0–22.0) vs. 1.0 (0–3.0), p < 0.001 and 15.0 (5.0–45.0) vs. 9.0 (2.0–15.0), p = 0.020, respectively]. NDI and number of MN in mononuclear lymphocytes were significantly lower in control subjects compared patients received CRT and those received only RT, but there was no significant difference between patients received CRT and those received only RT. Number of MN in binuclear lymphocytes was significantly lower in control subjects compared to patients received CRT, but there was no significant difference between control subjects and those received only RT. Also there was no significant difference between patients received CRT and those received only RT in terms of number of MN in binuclear lymphocytes.Conclusions: MN frequency of mononuclear and binuclear lymphocytes in medical follow-up of patients with head and neck cancer after RT could be important in evaluating cytogenetic damage of RT. However, further investigations are needed to provide quantitative correlations between MN yields and the clinical features in post-radiotherapy period.