Im 72 years old and i had an ultrasound done. they found a knot. what would the chances be that it's throat cancer?

Need clarification: Are you talking about the thyroid ultrasound with a "nodule"? Or the "knot" is a lump someplace else like esophagus , or skin?

A lymph node ?: What kind of ultrasound did you have? Is that for your thyroid or for other organ? Are you referring " a node as a lymph node"? Or nodule? Lymph node can be enlarged due to different reasons-i.e.Most commonly infection, inflammation, trauma etc.- however lymph node also can be enlarged when it is involved by malignancy.