Does interstitial HDR brachytherapy for breast cancer increase soft tissue fibrosis?

In breast conserving therapy a number of parameters influence the results of treatment. Our own studies have shown that among the risk factors responsible for fibrosis are: reference volume V100 (the volume of tissue surrounded by 100% isodose), V150 (volume of tissue surrounded by 150% isodose) and V200 (volume of tissue surrounded by 200% isodose).