Would you give breast radiotherapy to a patient with a history of bilateral retinoblastoma?

I would certainly be concerned about it, especially if patient has been tested and is positive for hereditary RB. The risk of a secondary malignancy in the RT field would increase many fold, especially bone or soft tissue sarcoma.

Although I have not treated anybody, I may consider the patient for partial breast RT to minimize the exposure of adjacent tissue, including bone and soft tissue, which may reduce the risk of a secondary malignancy.