Breast cancer

Hi my name is Debbie I was diagnosed with breast cancer in September 2019 I have had breast surgery know waiting for radiotherapy was told I would be having over Christmas but they can't fit me in until January, I just can't understand why I'm waiting so long to get this done I thought you had to have radiotherapy 4 to 6 weeks after surgery as it's more affective and the longer you wait the more chance it will come back