@della. I am not sure what LVI is ... maybe check with your Onc/Breast Care Nurse.
The margins is getting ‘clean flesh ‘ as well as the tumour, so they can confirm that they got all the tumour as well as surrounding clean flesh. The pathology report should indicate how much clean flesh was removed ( usually in mm’s). Ask your breast care nurse to check the margins - tho if they weren't 'clear' you would have been advised by now & possibly gone back for further surgery. So I am guessing that isn't something you need to worry about.
Yep, as @Fraser said - the role of the chemo is 'mopping up' any randoms that may have escaped ... hubby only had 1 positive node (out of 30 tested) and he still had chemo 'just in case'. I reckon with this disease, you don't want to be asking later on ... 'what if' ..... you've gotta chuck everything at it that you can .... so with discussion with your Onc, you'll work out a plan.
I only had radiation (chemo was never put on the table with me) so I was one of the lucky ones.
take care & all the best xx