Clinical Research Update: Risk Stratification in Thyroid Cancer

By Iain J. Nixon, MD,

Friday, October 25, 2013

With screening for thyroid cancer increasing among primary physicians worldwide, the number of cases being diagnosed is on the rise. In 2014 alone, 60,000 Americans are expected to be told that they have this malignancy (1).

At Memorial Sloan Kettering, our Head and Neck Service has a long tradition of publishing innovative clinical research and outcomes audits of patients undergoing surgery for thyroid cancer.

Our approach to the management of this condition has changed dramatically over the past century, however. Today it consists of surgery on the gland and surrounding lymph nodes. Following surgery, some patients are candidates for radioactive iodine treatment.

Critical Component: The GAMES Risk Stratification System

Early experience in treating patients with thyroid cancer led to the critical concept of risk stratification of candidates for radioactive iodine treatment. This can be useful in determining a treatment plan. Patients are grouped into low-, intermediate-, and high-risk categories, depending on their age, the size of their tumor, and features of the tumor itself

Over the course of the 1970s and 1980s, we developed the “GAMES” (gender, age, metastasis, extrathyroidal extension, size) risk stratification system, and continue to apply this approach to the management of our patients. Recent retrospective work evaluating our experience confirms the ongoing validity of this approach. (2)

Fortunately, the majority of patients with thyroid cancer are not at high risk of either recurrence or death. And not all patients require a total thyroidectomy with lymph node removal and radioactive iodine treatment. Accordingly, at our institution, all three of these modalities are applied to patients in a selective manner, based on their level of risk.

hanging trends in well differentiated thyroid carcinoma over eight decades.
Changing trends in well differentiated thyroid carcinoma over eight decades.
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Thyroidectomy and Lobectomy

At most cancer centers nationwide, the majority of thyroid cancer patients undergo a total thyroidectomy. This operation results in excellent outcomes, with very low rates of cancer recurrence and very high rates of survival.

However, the procedure is also associated with a small but significant risk of complications, including injury to the recurrent laryngeal nerve, which can cause hoarseness, or to the parathyroid glands, which can result in a long-term need for dietary supplementation with calcium.

An alternative approach for small thyroid cancers confined to the thyroid gland and without nodules in the opposite thyroid lobe is to perform a thyroid lobectomy. Our experience confirms that properly selected patients enjoy excellent outcomes following this approach, which also poses less of a risk for postoperative complications. (3)

Similarly, it is now common for surgeons to remove seemingly normal lymph nodes surrounding the thyroid gland during a procedure for cancer. Some experts contend that this more aggressive surgery will result in improved outcomes despite putting patients at increased surgical risk.

Again, our experience demonstrates that patients who have no evidence of disease in those glands can safely have them monitored rather than removed, reducing the injury to patients while maintaining the excellent outcomes expected in this patient group. (4)

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Post-Surgery Treatment

Radioactive iodine treatment has become standard in many centers following thyroid cancer surgery. This therapy can result in a dry mouth and difficulty swallowing.

Memorial Sloan Kettering investigators have demonstrated a link between the use of radioactive iodine and second cancers in patients who are considered at very low risk of recurrence with surgery alone. (5)

This work, performed at a national level, is reflected in our practice; by applying our GAMES system and selecting only patients at higher risk of recurrence, we have shown that many patients can safely be managed with surgery alone, without the use of radioactive iodine therapy. (6)

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The Future

Ongoing refinements to our risk stratification system and other work in thyroid cancer by our Head and Neck Service enables patients and clinicians to understand the prognosis of their disease and to select appropriate treatment.

We are committed to continuing our contemporary approach to the management of these patients, and to the promotion of this system of patient selection and treatment decision making in the larger community through our international leadership in fields of research and clinical care.

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