Boost radiation for breast cancer in the conservative surgery of mamma. The significance of surgical clip as the marker of the stump of mammary gland

In authors' facility, post lumpectomy 50 Gy was irradiated to the whole mamma and boost radiation of electron beam with 10 Gy was done in the case of pathologically positive mammary gland stump. For validation of setting the radiation field, the present study was performed to see whether the skin incision represents the mammary gland stump in comparison with CT images. The maximum distance between the incision and stump was measured on the flat roentgenograms taken vertically to the skin surface in 51 cases (52 mammae), to whose mammary gland stump the clip had been set previously. The S-S distance was in the range of 0.2-10.1 cm (average 3.1 cm). The tumor site was regardless of the distance. The distance tended to be large with the tumor size and was correlated with the fluid collection of the conserved mamma. Thus boost radiation field should be decided by the marker of mammary gland stump. (K.H.)