According to an article recently published in the International Journal of Cancer, high doses of vitamin E (alfa-tocopherol) taken during treatment for head and neck cancer do not appear to provide any benefit.

Standard therapy for head and neck cancer often includes radiation therapy, with or without chemotherapy and surgery. Some individuals have taken antioxidant supplements while on treatment to help lessen potential side effects of therapy. There has been concern, however, over the safety of antioxidants during treatment.In fact, high doses of vitamin E were associated with a 38% increased risk of mortality among these patients.

(Dr J: If you have been taking a vitamin E supplement, please don't fret about it. This study relates to those taking doses of vitamin E which were considered high, ranging from 16.5 to 2000 International Units (IU) per day (average was approximately 400 IU per day).

Patients who are undergoing treatment for cancer should discuss all medications and supplements they are taking with their physician.

Links:
Vitamin E Supplementation May Be Harmful in Head and Neck Cancer Patients
High Doses of Vitamin E Associated with Increased Mortality