[Changes in blood flow and skin reaction following radiation therapy]

Skin blood flow (SBF) during radiation therapy was measured and compared with skin reaction to examine the relationship between skin reaction and blood flow. The SBF of 50 patients including 16 with head and neck (H&N) cancer, 13 with breast cancer and eight with lung cancer were analyzed. In the H&N patients, SBF was increased according to the treated dose, while in the breast cancer patients SBF was slightly increased at 10 Gy, and did not change up to 40 Gy. In the lung cancer patients SBF was not increased until 20 Gy, and thereafter increased moderately at 30 Gy. Among H&N, breast and lung cancer patients, the most severe skin reaction was observed at the earliest time in breast cancer patients, while blood flow was only slightly increased. This must have resulted in a relatively higher skin dose than the reference point dose in breast cancer patients. Therefore, differences in the relationship between SBF and skin reaction were observed among different types of cancer patients. However, in H&N cancer patients, SBF was increased as skin dose increased. Skin blood flow could be a good indicator by which to estimate skin reaction quantitatively when the daily skin dose is around 1.6 Gy.