THYROID MALIGNANCYTREATMENT

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TNM Staging

• Tumour Tx: Primary cannot be assessed. T0: No evidence of primary. T1: Limited to thyroid, 2cm or less. T1a:</=1cm T1b:1cm </=2cm

T2:Limited to thyroid>2cm but <4cm. T3:Limited to thyroid >4cm. T4:Extending beyond the capsule any size. T4a: moderately advanced T4b:very advanced

• Nodes Nx: Cannot be assessed. N0: No regional node metastasis. N1: Regional node metastasis. N1a: level VI N1b:any level

• Metastases Mx: Cannot be assessed. M0: No metastasis. M1:Metastasis is present.

Stage under 45 yrs Over 45 yrsI. Any T, any N,M0 T1,N0,M0II. Any T, any N,M1 T2,N0,M0 III. T3,or T1,T2&N1a,M0IVA. T4orT1,T2,T3,T4a&N1b,M0 IVB. T4b,anyN,M0IVC AnyT,anyN,M1

Papillary carcinoma thyroid

• Treatment of primary A.Total thyroidectomy -Treatment of choice. -Entire thyroid gland is removed. -Reasons:a. Rich intrathyroidal lymphatic spread.b. Multicentric origin.

Procedure]

• Horizontal anterior neck incision• Create upper and lower flaps between the

platysma and strap muscles• Divide vertically between the strap muscles

and anterior jugular veins• Separate the strap muscles from the thyroid

gland• Divide the middle thyroid vein

• Mobilize the superior pole of the thyroid lobe. Divide the superior thyroid artery and vein close to the thyroid gland (avoid injury to the external branch of the superior laryngeal nerve and the superior parathyroid gland)

• Identify the recurrent laryngeal nerve whenever possible using the nerve monitoring device

• Identify the inferior parathyroid artery• Divide the inferior thyroid artery and vein

• Separate the thyroid lobe and isthmus from the trachea

• Repeat this process for the other thyroid lobe. Remove the thyroid gland

• Reapproximate the strap muscles• Reapproximate the platysma muscle• Close the skin with a subcuticular stitch

-Advantages: 1. Easy to detect and treat residual and metastatic

diseases.2. Eliminates contralteral occult cancer.3. Eliminates resurgery.4. Eliminates risk of recurrence, thus improving

survival.

.

After total thyroidectomy, thyroxine is not given for a period of 4 weeks so that thyroid remnants can be ablated with radioiodine.

Dose:30-100mCi.

B. Lobectomy -Removal of one lobe and entire isthumus. -Total thyroidectomy is recommended for

tumours greater than 2 cm and those with nodal involvement or metastasis.

-So lobectomy can be done for the remainder.

Advantages of lobectomy:a. No hormone replacement therapy.b. No hypoparathyroidism.c. Need not test thyroid function tests regularly.

• Treatment of secondaries in the lymph nodes

Mostly central neck nodes are cleared. If nodes are enlarged in the anterior triangle they are dissected and removed along with fat and fascia. This is called functional block dissection.

Structures such as internal jugular vein, sternomastoid muscle, accessory nerves are not removed because lymph nodes are slow growing and they rarely spread outside the capsule of the node.

• Suppression of the TSHThis is an aspect in the postoperative period

because papillary carcinoma is a TSH dependent tumour.

To prevent the patient developing hypothyroidism in the post op period and to suppress TSH, thyroxine 0.3 mg/day is given.

Patients who require regular radioiodine for scanning and ablation should be given T3 because it acts quickly and can be stopped and restarted quickly.

On the other hand, T4 has to be stopped almost 30 days prior to scanning and ablation rendering patients severely hypothyroid for 4 weeks. Dose:40-60micro gm/day.

Follicular carcinoma

• Treatment of primary When a patient has enlarged thyroid gland

and scalp swelling, total thyroidectomy is the treatment of choice.

Secondaries donot take up the radioisotope in the presence of primary tumour. Hence lobectomy or hemithyroidectomy should not be done.

• Treatment of metastasisAfter total thyroidectomy a whole body bone

scan is done to look for metastasis in the bone.

The secondaries can be treated by oral radioiodine therapy.

• Postoperative thyroxineIn the post op period patient should receive

thyroxine 0.3mg/day to suppress TSH and to supplement thyroxine.

Anaplastic carcinoma

• Due to the gross local infiltration into the vital structures in the neck such as common crotid artery and trachea, the resectabilty rate is low.

• However rarely isthumus can be excised so as to relieve compression of the trachea.

• Post operative radiotherapy is given as a palliative treatment.

Medullary carcinoma of thyroid

• Total thyroidectomy with radical neck dissection.

• The lymph nodes are treated by radical block dissection because they are fast growing when compared to papillary carcinoma.

• If there are multiple secondaries in the bone, oral 131I has no role because this tumour does not arise from thyroid cells. Only palliative radiotherapy can be given.