Turanli et al have published an article on completion thyroidectomy, including the incidence of microscopic papillary carcinoma involving the opposite lobe, the relationship of multicentricity in the ipsilateral lobe, and presence of microscopic carcinoma in the contralateral thyroid lobe. This is an interesting article and one of the many published series on completion thyroidectomy. The authors have performed completion thyroidectomy in 97 patients and found microscopic papillary carcinoma involving the opposite lobe in 20% of patients. They have shown that if a patient has a multicentric tumor on one side, there is a higher likelihood of having microscopic carcinoma on the other side. They have also justified and given the indications for completion thyroidectomy, the role of radioactive iodine ablation, which seems to be used routinely in their series, and the outcome of the surgical procedure and survival. It is interesting to note that patients with multicentric thyroid carcinoma on one side had a higher likelihood of having microscopic cancer on the other side.

However, there remain questions about the indications for completion thyroidectomy. The presence of microscopic thyroid cancer (laboratory cancer) is well known and is seen in approximately 5% of individuals undergoing autopsy studies. These microscopic laboratory cancers are quite common; we live with them, we grow with them, and we die with them. Such tumors are the natural biology of the human thyroid; however, they seem to have no long-term clinical implications. Similarly, the presence of microscopic papillary carcinoma in the opposite thyroid lobe also has not been found to have clinical implications. The role of completion thyroidectomy needs to be revisited, and the automatic reflex completion thyroidectomy needs to be reevaluated. Decisions regarding completion thyroidectomy should be based on the biology of the ipsilateral thyroid cancer, the aggressiveness of the thyroid cancer, and the strong need for radioactive iodine ablation for which completion thyroidectomy is necessary to facilitate therapy.

Interestingly, this article by Turanli et al does not refer at all to risk group stratification, which is very important in the evaluation, treatment, follow-up, and reporting of well-differentiated thyroid carcinoma. Risk group stratification, that is, low, intermediate, and high risk, is crucial for intraoperative surgical decision making, follow-up, and comparing survival results. Most past studies report survival based on risk group stratification . Survival in the low-risk group has been 99%, 85% for the intermediate risk group, whereas survival in the high-risk group was 57% . Clearly, one needs to be aggressive both surgically, in follow-up, and in considering the use of radioactive iodine (RAI) ablation in the intermediate and high-risk well-differentiated thyroid cancers. Completion thyroidectomy has no specific role in the management of low-risk thyroid cancer patients. Recently, there has been considerable interest in the surrogate marker during follow-up of patients with well-differentiated thyroid cancer with locoregional recurrence. With this concern in mind, in their recent guidelines, the American Thyroid Association has revised their recommendations for thyroid cancer and has divided thyroid cancers into low-, intermediate-, and high-risk groups . It not only include the Tumor-Node-Metastasis system, which is well known, but also include tumor-related histopathologic prognostic markers. This risk stratification is important, and follow-up decisions should be based on it. It also analyses the risk of recurrence, rather than survival alone. I do not believe that every patient with well-differentiated thyroid carcinoma presenting with a solitary thyroid nodule, which is clinically limited to one lobe, requires a completion thyroidectomy. Survival in this group of low-risk thyroid cancer patients exceeds 99%, and completion thyroidectomy and radioactive iodine ablation are unlikely to add any meaningful benefit . It may add, however, to increased complications related to nerve injury and hypoparathyroidism. If the ipsilateral nerve has been paralyzed during previous surgery, one must be extremely concerned about completion thyroidectomy. Any injury to the opposite nerve may lead to temporary or permanent tracheostomy. This should lead to serious concern about the role of completion thyroidectomy. It is important to recognize that “the punishment should fit the crime.”

Clearly, if the ipsilateral thyroid lobe reveals high-risk thyroid cancer by the patient’s age, size of the tumor, or histologic features, then an appropriate completion thyroidectomy should be considered mainly for the purpose of adjuvant therapy (such as RAI ablation), which could be very difficult in the presence of a normal thyroid lobe. Occasionally, a medical completion thyroidectomy can be performed with 75 mCi of RAI ablation, especially if the contralateral lobe is small or there have been complications related to ipsilateral surgery such as recurrent laryngeal nerve palsy or removal of both parathyroid glands. However, it takes 3 to 6 months for the remaining lobe to be made dysfunctional.

Another issue related to the controversy of completion thyroidectomy revolves around the timing of surgery. Most surgeons would prefer completion thyroidectomy be performed either in the first week when the inflammatory reaction is minimal, or after 2 to 3 months when the inflammation has subsided and surgical dissection is easier. Patients do develop considerable anxiety over delaying a completion thyroidectomy; however, it is our responsibility to explain to them the true nature of thyroid cancer and the considerations for completion thyroidectomy. Even though the reported risk of complications in the literature is no higher for completion thyroidectomy, one needs to remember that the risk of parathyroid injury and recurrent laryngeal nerve-related problems are slightly higher in this group of patients undergoing a secondary surgical procedure. If the patient has a multicentric tumor in one lobe, there is a possibility of having microscopic cancer on the contralateral lobe. This should be kept in mind because patients are always concerned about finding cancer on the other side, and they should be informed of such preoperatively.

The classic clinical scenario of completion thyroidectomy is a patient who presents with a solitary thyroid nodule. Invariably, the preoperative needle biopsy is suggestive of a follicular lesion. The patient undergoes a thyroid lobectomy with a nondiagnostic frozen section. The final report turns out to be follicular carcinoma. The knee jerk reflex around the country is to bring the patient back to the operating room for completion thyroidectomy. However, one needs to consider the biology of these tumors in clinical decision making. It is vitally important to discuss the diagnosis of follicular carcinoma with the pathologist. Most of these turn out to be minimally invasive follicular tumors with minimal capsular invasion, leading to the diagnosis of follicular carcinoma. Such tumors are nonthreatening cancers, and patient survival is excellent . There is hardly any reason for these patients to come back to the operating room for completion thyroidectomy. However, if there is a major capsular invasion or vascular invasion, it would be appropriate to bring the patient back for completion thyroidectomy so that the patient can be treated appropriately with radioactive iodine ablation. One of the major indications for completion thyroidectomy would be the need for radioactive iodine ablation.

One must define the high-risk nature of the primary tumor, high likelihood of local or regional recurrence, or a high incidence of distant metastasis. The clinical parameters include a large primary tumor, gross extrathyroidal extension, bulky nodal metastasis, or high-grade histology such as tall cell, poorly differentiated, or insular thyroid carcinoma. The indications based on molecular analysis of the tumor such as BRAF overexpression remain unclear at this time.

The debate related to completion thyroidectomy will continue until we understand the biology of thyroid cancer in much more detail and can explain recurrence, complications, and long-term survival to patients. However, in most low-risk patients, completion thyroidectomy can be avoided based on sound scientific reasons. This reminds me of the famous statement, “An operation not worth doing is not worth doing well.”