Thyroid nodules are common, often found incidentally. Most are benign, but some can be malignant, making accurate diagnosis challenging. Distinguishing these growths has been complex, causing uncertainty for patients and clinicians. Precise classification is important for appropriate management and to prevent unnecessary treatments.
Understanding NIFTP
Non-Invasive Follicular Thyroid Neoplasm with Papillary-like Nuclear Features, or NIFTP, refers to a specific type of thyroid nodule. The term “non-invasive” signifies that the lesion does not penetrate the surrounding thyroid tissue or its capsule. These nodules also exhibit “papillary-like nuclear features,” which are microscopic characteristics in the cell nuclei that resemble those seen in papillary thyroid cancer, but without the invasive growth pattern.
In 2016, experts reclassified encapsulated follicular variant of papillary thyroid carcinoma (EFVPTC) as NIFTP. This removed “carcinoma” from its name, recognizing its extremely low risk of recurrence and spread. The change reflected the benign behavior of these lesions, previously treated as cancer.
Why the NIFTP Reclassification is Significant
NIFTP reclassification positively impacts patients and the healthcare system. Previously, individuals diagnosed with NIFTP experienced the psychological burden and anxiety of a cancer diagnosis. This reclassification clarifies the lesion is not cancer, alleviating distress.
Beyond emotional relief, reclassification shifted treatment protocols from aggressive to less invasive approaches. Thyroid cancers often require total thyroidectomy and radioactive iodine therapy. For NIFTP, however, these extensive treatments are generally not needed, reducing risks like damage to parathyroid glands or vocal cord nerves. This also avoids overtreatment, lowering healthcare costs from unnecessary procedures, prolonged hospital stays, and follow-up care. The reclassification is estimated to affect 30,000 to 46,000 patients worldwide annually, significantly reducing potentially harmful treatments.
Diagnosis and Management of NIFTP
NIFTP is typically identified after surgical removal of a thyroid nodule. Initial evaluation often involves a fine needle aspiration (FNA) biopsy, which may suggest “follicular neoplasm” or “atypia of undetermined significance.” These results indicate a need for further investigation but do not definitively diagnose NIFTP.
A conclusive NIFTP diagnosis requires a pathologist to examine the entire removed nodule under a microscope. Pathologists look for specific criteria: complete encapsulation or clear demarcation, a follicular growth pattern without well-formed papillae or psammoma bodies, and nuclear features resembling papillary thyroid carcinoma but without invasion. Absence of tumor necrosis or high mitotic activity is also required.
Standard treatment for NIFTP is a lobectomy, removing only the half of the thyroid gland containing the nodule. This less extensive surgery is sufficient given NIFTP’s excellent prognosis, with recurrence rates estimated at less than 1% within 15 years. Radioactive iodine therapy, common for many thyroid cancers, is not recommended for NIFTP as it does not spread beyond the thyroid. Post-operative care typically involves regular monitoring with clinical examinations and thyroid function tests, less intensive than follow-up for malignant thyroid cancers.