ABSTRACT
Objective To investigate the application of superficial brachytherapy in the treatment of the upper arm skin invasion of breast cancer. Methods This study was conducted on a female patient with ipsilateral chest wall, axillary, and clavicle recurrence, and circumferential skin and subcutaneous soft tissue invasion in the ipsilateral upper arm after modified radical mastectomy for breast cancer. The upper arm lesions were treated with 192Ir high-dose-rate superficial brachytherapy at a dose of 50 Gy in 25 fractions. Dosimetric parameters were compared between superficial brachytherapy and electron irradiation plan. Treatment outcomes and adverse reactions were observed during and after treatment. Results The heterogeneity index(HI)for target volume was 1.62 and 1.94 in superficial brachytherapy and electron irradiation plan, respectively. The D90,D100, and V150%for clinical target volume were higher in superficial brachytherapy than in electron irradiation plan(205 vs. 189 cGy;163 vs. 110 cGy;6.3% vs. 3.23%). The D0.1,D1, and D2for the humerus were also higher in superficial brachytherapy than in electron irradiation plan(155 vs. 80 cGy;147 vs. 55 cGy;145 vs. 36 cGy)and much lower than the bone tolerance dose in both treatments. The lesions partially subsided after superficial brachytherapy. The main adverse reaction was grade 2 radiation dermatitis. Conclusions Compared with electron irradiation plan, superficial brachytherapy is a simple and effective approach for irradiation of shallow target volume with a large curvature, such as circumferential upper arm skin invasion of breast cancer. Superficial brachytherapy achieves satisfactory homogeneity and dose distribution.