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Well-Differentiated Thyroid Cancer: Determining the Best Amount of Surgery

Lindsey, Heather

doi: 10.1097/01.COT.0000450367.77422.96


Completion thyroidectomy is performed now only in a carefully selected group of intermediate- and low-risk patients with well-differentiated thyroid cancer (WDTC) at Memorial Sloan Kettering Cancer Center (MSKCC). A study published last month in Annals of Surgical Oncology (2014:21: 1374-1378) adds additional data to the long-standing question of how extensive surgery should be in such patients.

“We do feel very strongly that in the low-risk group, that lobectomy is the most appropriate and optimal treatment,” said the senior author, Ashok Shaha, MD, Professor of Surgery and the Jatin P. Shah Chair in Head and Neck Surgery. Notably, a previous study (Surgery 2012;151:571-579) at the center demonstrated no difference in 10-year overall survival between low-risk patients undergoing lobectomy or total thyroidectomy, he said.

Unilateral lobectomy may be useful for select patient populations, agreed Amy Y. Chen, MD, MPH, Professor in the Departments of Otolaryngology and Head and Neck Surgery and Hematology and Medical Oncology at Emory University School of Medicine. “This paper indicates that micro-carcinomas or other low-risk carcinomas do not need to have completion thyroidectomy.”

Still, said Amit Agrawal, MD, Associate Professor of Otolaryngology at Ohio State University Comprehensive Cancer Center—Arthur G. James Cancer Hospital and Richard J. Solove Research Institute, while the study is interesting, it evaluates only a small number of patients, so drawing conclusions is difficult. Overall, how much surgery is appropriate in thyroid cancer patients has been a raging controversy that goes back many decades, he said.

Shaha and his colleagues conducted a retrospective review identifying 79 patients who underwent a planned completion thyroidectomy for WDTC from 2001 to 2010, based on the pathology of an initial lobectomy. Overall, completion thyroidectomy represented only three percent of all thyroid operations performed at the center.

Thirty-eight percent of patients had received a lobectomy before arriving there. Lobectomy at MSKCC occurred in patients who had either nondiagnostic fine needle aspiration or small unifocal intrathyroidal cancers. Based on American Thyroid Association Initial Risk Stratification, 56 percent of patients were low risk and 44 percent were intermediate risk. Physicians recommended completion thyroidectomy for 64 patients, while 15 were given the option of surveillance but eventually decided to undergo surgery. The most common cancer found after the first surgery was papillary carcinoma (66%), followed by follicular (14%), Hürthle cell (10%), and the tall cell variant of papillary carcinoma (10%).

T3 and T2 tumors were more common in patients recommended to completion thyroidectomy. They were also significantly more likely to be intermediate risk and to have aggressive histology, such as vascular invasion and extrathyroidal extension.

Contralateral cancer occurred in 35 percent of the patients recommended to surgery and 33 percent of those recommended to surveillance. Overall, 89 percent of these cancers were micropapillary. Of the micropapillary cases, 40 percent were multifocal. Two patients had recurrence in their lungs at a median follow-up of 42.3 months.

Ninety-one percent of the patients recommended to have completion thyroidectomy received radioactive iodine therapy compared with 53 percent of those referred to surveillance.

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Lobectomy in Low-Risk Patients

Also asked for his opinion for this article, M. Boyd Gillespie, MD, MSc, Professor of Medicine in the Department of Otolaryngology–Head and Neck Surgery at Medical University of South Carolina (MUSC), said that lobectomy can be used to treat low-risk differentiated thyroid cancer patients, who most thyroid experts agree have tumors less than 1 cm in diameter.

However, he pointed out, the MSKCC group has an expanded definition of low risk including T1 (0–2 cm) or T2 (2–4 cm) tumors if they have a papillary histology, lack aggressive pathological variants, and have no nodal involvement and the patient is female and age 18 to 45.



In patients with large tumors, contralateral cancer, more aggressive tumor histology, or suspicious lymph nodes, completion thyroidectomy or total thyroidectomy is likely necessary, said Shaha.

MSKCC uses lobectomy to treat some small follicular cancers, which might be controversial because this form of malignancy can spread to distal sites, said Gillespie, adding that most centers would probably use total thyroidectomy.

Shaha noted that MSKCC oncologists divide follicular carcinoma into minimally invasive or widely invasive groups. The minimally invasive group has no risk for distant metastases and there is a survival rate of almost 100 percent, so completion thyroidectomy is not necessary.

Also asked for comment, Rohan R. Walvekar, MD, Director of the Head & Neck Service at MCLANO & Earl K. Long Hospitals and Director of Clinical Research & Salivary Endoscopy Service at Louisiana State University School of Medicine, said that follicular neoplasms by definition can't be diagnosed as cancer on a needle biopsy and need to be examined closely for vascular and thyroid capsular invasion. In this situation, a lobectomy would be an appropriate consideration, he said.

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Other Considerations

Another factor physicians should consider when assessing patients for lobectomy is whether patients can adhere to follow-up care, said Walvekar. Individuals who seek treatment at tertiary care centers like MSKCC are probably well educated, understand their disease and its consequences, and have good social support systems, all of which ensure good follow-up, he said. However, indigent and uninsured patients who lack a good social infrastructure and often face obstacles such as lack of transportation make follow-up surveillance “challenging or unlikely,” he said.

Moreover, patient care is not purely the surgeon's responsibility and needs to incorporate the opinion of endocrinologists and nuclear medicine specialists, he continued. Physicians will provide variation in treatment based on their previous experience and practice patterns. “You obviously look to national guidelines as a standard, but the team has to agree on individualized approaches.”

Patient preferences should also be considered. “Some people are not comfortable with the idea of having residual cancer no matter how small or how low the risk,” he said.



And, said Agrawal, patients may want to simplify their long-term follow-up, minimize their chance of having a second surgery down the road, or reduce their level of anxiety, and thus opt to undergo total or completion thyroidectomy.

Another consideration, Chen noted, is that lobectomy might be advantageous in elderly patients or patients with comorbidities who may not tolerate a second general anesthesia alone. The procedure may also be the better option if the patient is at risk of recurrent laryngeal nerve injury.

The procedure can also preserve the parathyroid glands, which are important to calcium metabolism, and avoids the complication of hypoparathyroidism, Gillespie said, adding that patients who undergo lobectomy can also avoid using hormone-replacement therapy, he said.

In experienced hands, completion or total thyroidectomy carries minimal added surgical risk compared with lobectomy, noted Agrawal. Even patients who undergo lobectomy alone will still need long-term oncologic follow-up as well as management from an endocrinologic perspective, since the procedure does not necessarily avoid the need for thyroid-replacement therapy.

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Lobectomy Follow-up

Surveillance after lobectomy should be conducted by a multidisciplinary team, including endocrinologists who can assist in determining the frequency of follow-up procedures such as periodic ultrasound, said Agrawal. Since additional cancers can potentially develop in the other lobe, in the lymph nodes, or in other sites, patients must be carefully monitored.



Chen said that while the rates of contralateral cancer found after completion thyroidectomy at MSKCC were not concerning, the fact that they were not zero may make some physicians reluctant to give up their practice of performing completion thyroidectomy.

And, said Shaha, although contralateral cancers were identified in 34 percent of specimens in the study after completion thyroidectomy, the majority of these patients had micropapillary disease, which is unlikely to become clinically relevant, making completion thyroidectomy unwarranted. Micropapillary tumors without consequence are also common in the general population, he added. Still, patients who undergo lobectomy do need to receive close surveillance at least once a year for a few years.

The rate of contralateral cancer found in this study is “a good statistic to discuss with patients so they can make an informed decision about completion thyroidectomy,” said Gillespie. The argument for lobectomy still being an appropriate approach is that if contralateral cancers grow, patients can undergo surgery at a later date without minimizing the chance of cure.

However, the flip side to this argument is these microcancers may occur in individuals who have already developed a tumor on one side of their thyroid that needed removal, indicating they are at risk of malignancy, said Gillespie.

Moreover, physicians do see a fair amount of aggressive thyroid cancer, which can cause worry about a more than 30 percent incidence in the contralateral lobe, Walvekar said.

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Lobectomy at Select Centers More Feasible

Total removal of the thyroid and follow-up radioactive iodine (RAI) therapy is still the gold standard in many places, said Gillespie. “Cure rates are outstanding, so you always have to be careful when suggesting a less aggressive approach. It can make some people nervous.” However, at select centers such as MSKCC, using lobectomy in patients with the right risk profile is feasible.



While not always the case, physicians at non-academic centers or community hospitals might feel more comfortable performing a completion thyroidectomy followed by RAI for some of the patients MSKCC would choose to observe, Walvekar said.

Additionally, for patients in rural communities who may have trouble keeping follow-up appointments due to travel distances, completion or total thyroidectomy may make more sense, said Gillespie.

Shaha noted that he and his colleagues do believe that other centers may be overusing completion thyroidectomy—“although we don't have much data to support this. I think overuse may be a knee jerk reflex—i.e., cancer is on one side, then you have to take out the other lobe.” Another reason may be that the endocrinologist wants to give the patient RAI, which necessitates completion thyroidectomy.

© 2014 by Lippincott Williams & Wilkins, Inc.
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