Hurthle Cell Carcinoma Follow-up

Updated: Jan 29, 2018
  • Author: Serhat Aytug, MD; Chief Editor: Neetu Radhakrishnan, MD  more...
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Follow-up

Further Outpatient Care

Outpatient care includes the following:

  • Monitor for signs of hypothyroidism after surgical treatment

  • Levothyroxine therapy should usually be started after the treatment dose of 131I is administered

  • Monitor the patient for signs of hypocalcemia and measure calcium levels

  • Before scanning, instruct the patient to avoid iodine-containing medications and iodine-rich foods; measure urinary iodine in doubtful cases

  • In women of childbearing age, pregnancy must be ruled out

  • Patients should be instructed carefully about radiation precautions prior to 131I treatment and should follow the instructions meticulously when sent home

Thyroxine treatment

The adequacy of therapy is monitored by measuring serum thyroid-stimulating hormone (TSH) approximately 8-12 weeks after treatment begins, with the initial goal being a serum TSH concentration of 0.1 µU/mL or less and a serum T3 concentration within the reference range.

In patients who are at low risk and considered cured, the dose of levothyroxine (T4) is decreased to maintain a low, but detectable, serum TSH concentration (0.1-0.5 µU/mL). In higher-risk patients, higher doses are continued, targeting a serum TSH concentration of 0.1 µU/mL or less.

Clinical and ultrasonographic examinations

Thyroid bed and lymph node areas should be examined routinely. Ultrasonography is recommended in patients at high risk for recurrent disease and in any patient with suspicious clinical findings. Palpable lymph nodes that are small, thin, or reduced in size after an interval of 3 months can be considered benign.

Thyroglobulin measurement

In the follow-up care of patients, thyroglobulin is used as a marker of residual disease, of disease recurrence, and as a prognostic factor. Thyroglobulin is produced only by normal or neoplastic thyroid follicular cells and should be undetectable in patients who have been treated with surgery and radioablation. Thyroglobulin concentrations as low as 1 ng/mL or even lower can be detected with current assays.

Antithyroglobulin antibodies, which are found in approximately 15% of patients with thyroid carcinoma, can produce artifactual alteration in thyroglobulin assay results. These antibodies should always be checked when serum thyroglobulin is measured.

Serum thyroglobulin concentrations were undetectable in a group of patients receiving T4 treatment who have isolated lymph node metastases; therefore, undetectable values do not rule out metastatic lymph node disease. If the patient is thought to have metastases, a lymph node biopsy may be performed.

Chest x-ray

Most patients with abnormal chest x-ray findings have detectable serum thyroglobulin concentrations; therefore, this study might not have an additional value in diagnosing metastatic disease. However, it still can have a limited diagnostic value in a subgroup of patients.

Iodine-131 total body scanning

If the serum thyroglobulin concentration becomes detectable in patients receiving T4, recombinant human thyrotropin (thyrotropin alfa; Thyrogen) should be administered or the T4 should be withdrawn, an131 I total-body scan should be obtained, and serum thyroglobulin should be measured. The uptake of 131I and the level of TSH concentration determine the accuracy of total body scanning. In patients whose T4 is withheld, the serum TSH concentration usually should be higher than 30 µU/mL when the total-body scan is performed.

Intramuscular injection of thyrotropin alfa is a promising alternative because T4 treatment does not need to be discontinued and the adverse effects are minimal. Thyroglobulin measurement and total body scanning after thyrotropin alfa administration is currently the standard of care in many institutions. For routine diagnostic scans, 2-5 mCi (74-185 mBq [millibecquerel]) of 131I is administered; higher doses may reduce the uptake of a subsequent therapeutic dose of 131I.

Scanning is performed to measure uptake, if any, 3 days after the thyrotropin alfa dose has been administered. In certain situations, uptake cannot be detected with diagnostic scans when 2-5 mCi of 131I is administered but may be detectable after the administration of 100 mCi. This is the rationale for administering 100 mCi (or more) of 131I in patients with elevated serum thyroglobulin concentrations (usually levels >10 ng/mL after T4 has been withdrawn). If this approach is taken, total-body scanning should be performed 4-7 days later.

If any uptake is detected on the 131I total-body scan or the serum thyroglobulin concentration rises above the previous level, 131I therapy should be administered or a positron emission tomography (PET) scan should be considered to localize the metastasis/recurrence.

In the absence of 131I uptake, a CT scan of the neck and lungs, bone scintigraphy, and scintigraphy using a less-specific tracer (eg, thallium, tetrofosmin, fluorodeoxyglucose) and particularly PET scan should be considered strongly in patients with Hürthle cell carcinoma who are known to have no or low uptake.

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Further Inpatient Care

Standard postsurgical care is usually adequate. Monitor patients for signs of infection or hematoma formation.

Clinically monitor patients for hypocalcemic signs and check calcium levels at least every 12-24 hours. If hypocalcemia is present, immediately treat the patient.

Monitor patient for signs of laryngeal nerve injury (eg, hoarseness, respiratory compromise).

If the patient is hospitalized for 131I treatment, administer antiemetics and adequate hydration. Follow effective radiation precautions.

Salivary dysfunction secondary to uptake in salivary glands can be managed with adequate hydration and sucking on candies.

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Deterrence/Prevention

No specific prevention is available, although avoidance of radioactive exposure and adequate iodide intake can be considered preventive measures.

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Complications

Surgical complications include laryngeal nerve injury and transient or permanent hypoparathyroidism. Other surgical complications are infection and hematoma. Surgical scars in the neck can be cosmetically disturbing in certain individuals.

Nonsurgical complications

Hypothyroidism can occur if replacement therapy is inadequate. Hyperthyroidism can occur if the patient is overtreated with levothyroxine.

Acute adverse effects include the following:

  • Nausea or vomiting sialadenitis

  • Radiation-induced effects

  • Thyroiditis

  • In metastatic cases, radiation-induced fibrosis of the lung when large doses of131 I (>150 mCi) are administered at short intervals

  • Mild pancytopenia observed after repeated131 I therapy, particularly in patients with bone metastases who also have received external radiotherapy

Genetic defects and infertility may include the following:

  • Transient reduction in spermatogenesis

  • Transient ovarian failure

  • Increased frequency of miscarriages

The risk of secondary carcinoma or leukemia increased only in patients who have received a high cumulative dose of131 I (>500 mCi) and those who also receive external radiation therapy

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Prognosis

Hürthle cell carcinomas behave in a more aggressive fashion than other well-differentiated thyroid cancers, as evidenced by a higher incidence of metastasis and a lower survival rate. Hürthle cell carcinomas produce thyroglobulin. In addition, most Hürthle cell carcinomas have decreased avidity for 131I; therefore, treatment with radioactive iodide has limited efficacy.

In some series, nuclear aneuploidy is present in as many as 90% of patients with Hürthle cell carcinoma; in some studies, this condition is shown to be associated with an adverse prognosis.

In a retrospective review of all patients treated with Hürthle cell carcinoma at their institution between 1946 and 2003 (62 patients in all), Mills et al found that independent predictors of disease-free survival were lymph node status (P = 0.008), presence of metastases at diagnosis (P = 0.005), and tumor stage (P = 0.009). These authors suggest that radical surgery may improve outcome; on multivariate analysis, extent of surgery (P< 0.001) was the only independent factor that affected cause-specific survival. [37]

In a large retrospective study that analyzed the Surveillance, Epidemiology, and End Results (SEER) database from 1988-2009, 3311 patients with Hürthle cell cancer were identified and compared with 59,585 patients with other types of differentiated thyroid cancer. Overall disease-specific survival rates were lower for patients with Hürthle cell cancer (P< 0.001), indicating that Hürthle cell cancer has more aggressive behavior and compromises survival more than other types of differentiated thyroid cancer. [38]

In a study of 239 patients with Hürthle cell cancer treated at a single institution from 1995 to 2014, Oluic et al reported 5-, 10-, and 20-year cancer-specific survival rates of 94.6%, 92.5%, and 87.4%, respectively. Involvement of both thyroid lobes and the need for reoperation due to local relapse were unfavorable independent prognostic factors, while total thyroidectomy as the primary procedure was a favorable predictive factor for cancer-specific survival. [39]

 

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Patient Education

The need for life-long levothyroxine treatment should be explained to all patients. Radiation precautions should be explained clearly and in detail to patients who will be receiving radioactive iodine treatment. Women of childbearing age should be advised not to become pregnant for at least 1 year after treatment with131 I .

For patient education information, see the Thyroid and Metabolism Center, as well as Thyroid Problems.

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