Thyroid nodules that are benign by FNAC or in ultrasound or too small to biopsy can always be followed up. Fortunately, more than 90% of thyroid nodules are not cancers. But still, a careful clinical examination by the endocrinologist and appropriate investigations is always advised. Physical examination and ultrasound may be recommended by the doctor every 6 to 12 months. Sometimes nodules can grow, sometimes shrink, or sometimes stay the same over time. Some changes in the nodules may not merit further investigations but some may. The treating endocrinologist may decide that some changes are suspicious and order a repeat FNAC or closer follow up.
Although rare, we sometimes see nodules which look benign become cancerous over time. So, it is important that you are in follow up with your endocrinologist at least on an annual basis.