Thyroid cancer

Key points

Papillary - most common - regional lymph node (LN) metastases

Follicular - metastases to lung + bone. LN rare - more common in iodine deficient areas

Anaplastic - very rare

Lymphoma - very rare

Medullary - rare - in association with MEN2 - serum calcitonin is marker

Prophylactic total thyroidectomy:

MEN 2A :

American Thyroid association High risk (ATA H): Age 5 or earlier if raised calcitonin

Moderate risk (ATA MOD): Calcitonin screening every 6 months starting age 5

MEN2B: Age 1

Standard scenario

Approach to thyroid problem/mass

Is it

Cancer?

Hormonally active? (cancers almost never are)

Causing compression

Do history, examination and bloods to investigate

Get USS

U classification system by British Thyroid Association

Grades 1-5. If >3, get Fine needle aspiration for cytology

Cytology is graded by Thy classification

Grades 1-5. 5 indicates malignancy

CT if USS evidence of metastases

Discuss in MDT

Operation:

If low risk lesion - initial hemithyroidectomy - decision about completion total thyroidectomy at later date based on histology

If high risk or large lesion - total thyroidectomy

Post op:

Give T4 and measure TSH suppressed thyroglobulin - if low, continue

If thyroglobulin high consider 131I ablation

Check calcium

Iodine uptake scan 123I 6 weeks after total thyroidectomy to check residual and metastases

USS and thyroglobulin level follow up

Medullary:

Total thyroidectomy

Post op monitoring of calcitonin

No role for I131

References

British Thyroid Association Guidelines for the Management of Thyroid Cancer 2014 https://onlinelibrary.wiley.com/doi/pdf/10.1111/cen.12515

Wells SA Jr et al; American Thyroid Association Guidelines Task Force on Medullary Thyroid Carcinoma. Revised American Thyroid Association guidelines for the management of medullary thyroid carcinoma. Thyroid. 2015 Jun;25(6):567-610. doi: 10.1089/thy.2014.0335. PMID: 25810047; PMCID: PMC4490627.