What are methods practised for staging papillary thyroid cancer? Not about my single fna test "suspicious for malignancy" (category 5) but more info.

Surgery + more tests. Staging for any cancer is based on pathology based on examination of the thyroid gland tissue: i.e. If it extends beyond the gland itself after it is removed, and if there are involved lymph nodes and on the findings of scans looking for spread to other organs. But the staging rests on a definitive diagnosis based on surgery. You need the surgical findings first.
Staging Criteria. For thyroid cancer, there are many different staging systems, but most use the following criteria: age at time of surgery, size of primary tumor, extent of tumor (lymph nodes, growth outside of thyroid into neck tissues), completeness of surgery, and presence of distant metastases.