How would you manage an elderly patient with clinical stage IIIC ER positive breast cancer who refuses surgery, chemo and radiation treatment and willing to take only oral medications?  

My approach would be to start the patient on an aromatase inhibitor. Since this treatment would not be considered curable and treatment goal would be palliative, a case can be made for consideration of adding CDK 4/6 inhibitor, especially if her disease is considered inoperable due to advance stage.

I agree with @Robert Wesolowski. If patient is only receptive to oral medicines, I would approach this as first line "unresectable" breast cancer, and use AI + CDK 4/6i, as we know the likelihood of cure is low without multidisciplinary management.