Post breast reconstruction: Afraid of long term side effects of radiotherapy - is there any chance not to take radiotherapy?

In August 2016 , I made excisional biopsy in rt breast , it was mucinous carcinoma , tumour size is 6*5*3 cm with an inadequate margin. After 15 days I got nipple sparring mastectomy with level 1&2 axillary lymph node dissection &Latissimus dorsi reconstruction Pathology revealed 0/18 free lymph nodes, free margins , ER 8/8 , PR 8/8 , HER2 zero and KI67 8% I want to know if hormonal treatment is enough and there is no need for radiotherapy ? or raiotherapy is needed ?

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