Having recently had an excisional biopsy for two intraductal papillomas, I can relate to your concerns. I can only share with you the statements of my breast surgeon (who has done numerous surgeries of this type). He stated that the primary reason for removing the papilloma is to be certain that a papillary carcinoma is not "hiding" and the full pathology exam is the only and best way to make certain no malignant cells are present.
Papillary carcinoma is quite rare, accounting for only 1% to 2% of all breast cancer patients.
That being said, the excision of benign papillomas is the standard of care and percentages are not always predictable (it depends on the size of the sample subjects) and is variable based on who you reference. The majority of these lesions are benign on pathology and there is no direct indication that they will grow back. The risk of developing breast cancer after having a benign papilloma is only slightly increased over the risk of the general population developing breast cancer.
Hope this helps answer your questions. Best wishes if you are scheduling surgery!