Anyone discover cancer after leaking milk from a single duct?

Couldn't find a suitable flair. Hope its ok. Please help if possible. Breastfed almost 6 years ago. About 2 years ago started having an itch in the left nipple then noticed a mini bump over a single duct on the side of the nipple. (The itch was just irritation due to the dry milk in the duct and always stops as soon as i squeeze the milk out). Squeezed to find a very small bit/ mini stream of thick/dry milk. Not sure how to describe it. Like curdled milk. Very thin stream. Only makes up a tiny drop of milk. I clean it out once a week. Takes about a week to build up a drop. It's always white. Doctor always stated it's fine and could just be a faulty duct. Last week another doctor decided to book me for an ultrasound. I'm scheduled to go in two days. They may also do a mammogram. Feeling very afraid. Anyone have something similar happen and find breast cancer or just a duct issue?