The findings reported by Yamashita et al are due to a multitude of factors. The increase in age of patients given a diagnosis of papillary thyroid cancers during 3 consecutive decades is likely secondary to the increased longevity experienced by the overall population. Two factors exist that may contribute to the decrease in tumor size seen over time: (1) ultrasonography is more readily available and thereby identifies lesions that are smaller and not obvious clinically; and (2) fine needle aspiration biopsy, introduced during the 1950s, is more universally available and also can identify cancers at an earlier stage. The improvement in disease-specific survival is probably secondary to a change in the reported overall treatment of these patients. First, by identifying lesions at an earlier stage, one introduces the concept of lead-time bias, which can contribute to perceived overall improved survival. Second, the authors report an increase in the number of subtotal and total thyroidectomies performed, a practice that others report is associated with overall improved survival. Of note, the authors use radioiodine therapy only for distant metastases. The detection of distant metastases by radioiodine scan could only be made, however, if the patient had undergone subtotal or total thyroidectomy. Finally, we also know, based on a retrospective study, that near-total or total thyroidectomy and radioiodine therapy are associated with overall improved survival and decreased local recurrence.1 While Yamashita et al report interesting trends in the presentation of patients with papillary thyroid cancer, the phenomena most likely are due to changing practice patterns in the management of thyroid nodules and in the management of thyroid carcinoma.
Zeiger MA. Changing Trends and Prognoses for Patients With Papillary Thyroid Cancer—Invited Critique. Arch Surg. 1998;133(10):1065. doi:10.1001/archsurg.133.10.1065