AKT · ENT/Neck & thyroid

Thyroid cancer

Malignancy of thyroid follicular or parafollicular (C) cells

Overview

Malignancy of the thyroid. Differentiated cancers (PAPILLARY — commonest, and follicular) have a good prognosis; medullary (C-cell, calcitonin, MEN2 association) and anaplastic (elderly, aggressive) are less common. Often presents as a thyroid nodule or neck lump found on nodule work-up.

Recognise

Papillary (commonest): younger patients, spreads via LYMPH nodes, excellent prognosis
Follicular: spreads HAEMATOGENOUSLY (lung/bone); medullary: from parafollicular C cells, secretes CALCITONIN, associated with MEN2 (screen RET)
Anaplastic: elderly, rapidly enlarging hard mass with compressive symptoms, poor prognosis

Red flags

Rapidly growing hard fixed mass, hoarseness, stridor/dysphagia (compression), cervical nodes → urgent ENT/endocrine

Differentials & how to tell them apart

Benign thyroid nodule/goitrereassuring ultrasound + benign cytology

Lymphoma (thyroid)rapidly enlarging in a background of Hashimoto thyroiditis

Anaplastic carcinomaelderly, rapidly enlarging, hard fixed — aggressive

Parathyroid/other neck massbiochemistry/imaging

Investigations

Ultrasound + FNA cytology (the key diagnostics). Calcitonin if medullary suspected (+ RET/MEN2 screen and phaeochromocytoma exclusion before surgery). Staging imaging. (Note: thyroglobulin is a post-treatment tumour marker, not for diagnosis.)

Management

Surgery (thyroidectomy) ± radioiodine; lifelong levothyroxine

1Diagnose by ultrasound + FNA; refer to the thyroid MDT. Differentiated (papillary/follicular) cancer → thyroidectomy ± radioactive iodine, then TSH-suppressive levothyroxine.Gate: Medullary thyroid cancer is a C-cell tumour (raised CALCITONIN, MEN2/RET association) — it does NOT take up radioiodine and mandates an MEN2 work-up (exclude phaeochromocytoma before surgery); so the histological type changes the entire treatment plan
2Thyroglobulin as a follow-up marker for differentiated cancer; anaplastic cancer → palliative/airway-focused care; lifelong surveillance.

Surgery (thyroidectomy ± neck dissection) — the mainstay for differentiated and medullary cancer

Radioactive iodine — ablation for differentiated (papillary/follicular) cancer

Levothyroxine (TSH suppression) — after thyroidectomy — replacement + suppress TSH-driven recurrence

Key points

Papillary = commonest + lymphatic + good prognosis. Follicular = haematogenous. Medullary = calcitonin + MEN2 (no radioiodine). Anaplastic = elderly, aggressive. FNA is the diagnostic test.

Monitor & prognosis

Thyroglobulin/calcitonin, imaging, TSH on suppression; recurrence.

Excellent for differentiated; poor for anaplastic.

Source: British Thyroid Association; NICE NG12