Nonoperative Management Should Be Used With Caution in Patients With Small Papillary Thyroid Tumors
In a population-based study of patients with thyroid cancer, 12.3% of patients with small papillary thyroid tumors experienced thyroid cancer–related deaths despite undergoing thyroidectomy, according to a report by Nilubol and Kebebew in the journal Cancer. From the results of this study, the investigators suggested that nonoperative management of patients with small papillary thyroid tumors should be used with caution and that patients aged ≥ 45 years with papillary thyroid tumors ≤ 2 cm should undergo thyroidectomy.
One of the more difficult challenges facing oncology professionals who treat patients with thyroid cancer centers is when to choose thyroidectomy vs active surveillance, particularly in patients with small papillary thyroid tumors (≤ 2 cm). Papillary thyroid cancer, which accounts for > 80% of all thyroid malignancies, is associated with a good prognosis compared with other histologic subtypes. In addition, 87% of papillary thyroid cancer cases are attributed to small papillary thyroid tumors.
The need to treat the growing number of patients (63,000 new cases/yr) who have low-risk, small papillary thyroid tumors has been questioned, because some investigators have demonstrated that active surveillance in such patients results in no disease progression for the majority of patients and few to no adverse events. However, minimal research has been conducted on the relationship between low-risk papillary thyroid cancer and mortality rates.
With that in mind, Nilubol and Kebebew conducted a population-based study to determine the impact of papillary thyroid tumors ≤ 2 cm on mortality and to identify whether any risk factors are associated with mortality in this patient population.
Study Details
Using data from the Surveillance, Epidemiology, and End Results Program of the National Cancer Institute, the investigators identified 61,523 adult patients (aged ≥ 20 years) who were diagnosed with thyroid cancer (excluding medullary thyroid cancer) from 1988 to 2007. Of that total patient population, 1,753 patients died of thyroid cancer–related causes. The histologic differentiation grades analyzed were well-differentiated thyroid cancer, moderately differentiated thyroid cancer, poorly differentiated thyroid cancer, and undifferentiated (anaplastic) primary cancer.
The patient population was divided into two main cohorts according to age: < 45 years or ≥ 45 years. Those cohorts were further subdivided by gender and race/ethnicity.
Key Data
Of the 1,753 patients who experienced thyroid cancer–related mortality, 28.8% had classic papillary thyroid cancer, 9.4% had the follicular variant of papillary thyroid cancer, 10.1% had follicular thyroid cancer, 3.7% had Hurthle cell carcinoma, 16.7% had other histologic subtypes (such as tall cell, columnar, insular, or poorly differentiated thyroid cancer), and 31.3% had anaplastic thyroid cancer. As expected, the rate of patients diagnosed with papillary thyroid cancers ≤ 2 cm in the second decade of the study cohort (1998–2007) was significantly higher than the rate in the first decade (1988–1997): 58.2% vs 52.8% (P < .01).
One of the most significant findings of this study was that 12.3% of patients who underwent thyroidectomy and who died of thyroid cancer had small papillary thyroid tumors. In addition, disease-specific survival among patients with papillary thyroid tumors ≤ 2 cm was significantly shorter for men and for patients aged ≥ 45 years. Thus, the only independent prognostic factor for thyroid cancer–related mortality that can be used reliably to risk stratify patients with papillary thyroid tumors ≤ 2 cm is age ≥ 45 years.
Closing Thoughts
According to the investigators, the results of this study showed that 12.3% of deaths related to thyroid cancer occurred in patients with papillary thyroid tumors ≤ 2 cm who underwent thyroidectomy. They also noted that the only independent prognostic factor for thyroid cancer-related mortality that can be used reliably to risk stratify patients with papillary thyroid cancers ≤ 2 cm is age ≥ 45 years. Although male gender was not an independent prognostic factor, men had higher rates of extrathyroidal extension, regional lymph node and distant metastases, and mortality compared with women, regardless of age.
“Given the rise in the incidence of small thyroid cancers, nonoperative management for this growing population of patients should be used with caution. Patients aged ≥ 45 years or men of any age with a papillary thyroid tumor ≤ 2 cm should undergo at least thyroid lobectomy,” the investigators concluded.
Naris Nilubol, MD, of the Endocrine Oncology Branch, National Cancer Institute, Clinical Research Center, Bethesda, Maryland, is the corresponding author of this article in Cancer.
The authors disclosed no potential conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
