Unrelated cancer?

Hi everyone, I have just rejoined this forum. I had breast cancer four years ago for which I had chemotherapy. Had a dreadful time and had almost every side-effect going, including a pulmonary embolism. I also had thrush quite badly on the side of my tongue. After this had been treated it left some white patches which would not go away. This was diagnosed as leukoplakia (pre-cancerous tumour which becomes cancerous in 5 - 10% of cases). This year I was diagnosed with tongue cancer, for which I have just had surgery. Fortunately I don’t need any further treatment at the moment. I have been assured that this is nothing to do with the breast cancer (its a completely different type of cancer) but I do wonder whether the thrush had anything to do with it. Has anyone come upon anything like this before?