Radiotherapy involves production of reactive oxygen species (ROS) and induces oxidative stress condition which attributed to the impairment of antioxidant defense mechanisms in the body. This study was designed to evaluate the effect of antioxidant drugs (vitamins C and E, allopurinol, aspirin and melatonin) on the oxidative stress, biochemical and hematological parameters during exposure to radiotherapy in women with breast cancer. 95 women were studied, 20 healthy control women and 75 had breast cancer and were allocated into 5 subgroups. Each subgroup received specific antioxidant drug for four weeks during radiation therapy.
Malondialdehyde and glutathione (in erythrocytes and plasma), biochemical parameters (total plasma proteins, plasma albumin, uric acid and plasma calcium) levels, and hematological parameters (hemoglobin, white blood cell counts, platelets counts) all parameters were measured pre- and post radiotherapy for 4 weeks.
The results in this study showed an increase in the oxidative stress in both cancer and radiotherapy (increased Malondialdehyde and decrease glutathione levels) which is improved by antioxidant drugs, however melatonin showed a more potent action as antioxidant effect than other.
Antioxidant drugs produced significant elevation in total plasma protein, in addition vitamins (C and E), and melatonin show a significant elevation in plasma albumin levels also. The elevated plasma uric acid value in cancer patients did not show any changes with antioxidants. All antioxidant drugs treatment reduces plasma calcium level compared with pre treatment levels.
The results also showed no effect on hematological parameters after treatment with antioxidant drugs except for aspirin, in which it improves hemoglobin levels, meanwhile allopurinol and melatonin increase white blood cell counts previously reduced after exposure to radiation.
In conclusion the antioxidant drugs, especially melatonin, used in this study may limit some of the side effects of radiation and can be used as an adjuvant with radiotherapy. Key words: breast cancer, radiotherapy, oxidative stress, some biochemical and hematological parameters, antioxidant drugs.