Papillary Thyroid Carcinoma Managed at the Mayo Clinic during Six Decades (1940–1999): Temporal Trends in Initial Therapy and Long‐term Outcome in 2444 Consecutively Treated Patients

Abstract

It is uncertain whether more extensive primary surgery and increasing use of radioiodine remnant ablation (RRA) for papillary thyroid carcinoma (PTC) have resulted in improved rates of cause-specific mortality (CSM) and tumor recurrence (TR). Details of the initial presentation, therapy, and outcome of 2444 PTC patients consecutively treated during 1940-1999 were recorded in a computerized database. Patients were followed for more than 43,000 patient-years. The 25-year rates for CSM and TR were 5% and 14%, respectively. Temporal trends were analyzed for six decades. During the six decades, the proportion with initial MACIS (distant Metastasis, patient Age, Completeness of resection, local Invasion, and tumor Size) scores <6 were 77%, 82%, 84%, 86%, 85%, and 82%, respectively (p = 0.06). Lobectomy accounted for 70% of initial procedures during 1940-1949 and 22% during 1950-1959; during 1960-1999 bilateral lobar resection (BLR) accounted for 91% of surgeries (p <0.001). RRA after BLR was performed during 1950-1969 in 3% but increased to 18%, 57%, and 46% in successive decades (p <0.001). The 40-year rates for CSM and TR during 1940-1949 were significantly higher (p = 0.002) than during 1950-1999. During the last 50 years the 10-year CSM and TR rates for the 2286 cases did not significantly change with successive decades. Moreover, the 10-year rates for CSM and TR were not significantly improved during the last five decades of the study, either for the 1917 MACIS <6 patients or the 369 MACIS < 6 patients. Increasing use of RRA has not apparently improved the already excellent outcome, achieved before 1970, in low risk (MACIS <6) PTC patients managed by near-total thyroidectomy and conservative nodal excision.

Management Guidelines for Patients with Thyroid Nodules and Differentiated Thyroid Cancer: The American Thyroid Association Guidelines Taskforce

“…However, other similar studies show no such benefit, at least among the majority of patients with papillary thyroid carcinoma, who are at the lowest risk for mortality (68,101,(128)(129)(130)(131). In those studies that show benefit, the advantage appears to be restricted to patients with larger tumors (Ͼ 1.5 cm), or with residual disease after surgery, while lower risk patients do not show evidence for benefit (68,98,132). No prospective studies have been performed to address this question (128).…”

“…Near-total or total thyroidectomy is recommended if any of the following are present: the primary thyroid carcinoma is more than 1-1.5 cm, contralateral thyroid nodules, regional or distant metastases, patient has a personal history of radiation therapy to the head and neck, or a first-degree family history of differentiated thyroid cancer. Older age (Ͼ 45 years) may also be a criterion for recommending near-total or total thyroidectomy because of higher recurrence rates in this age group (62,68,69,95,96). Increased extent of primary surgery may improve survival for high-risk patients (97-99), while rates of recurrence are reduced by total-or near-total thyroidectomy even among low-risk patients (68,100,101).…”

“…In thyroid cancer, the AJCC/UICC Stage does not take account of several additional independent prognostic variables and may risk misclassification of some patients. Numerous other schemes have been developed in an effort to achieve more accurate risk factor stratification, including CAEORTC, AGES, AMES, U of C, MACIS, OSU, MSKCC, and NTCTCS systems (61, 62,68,98,[122][123][124][125]. These schemes take into account a number of factors identified as prognostic for outcome in multivariate analysis of retrospective studies, with the most predictive factors generally being regarded as the presence of distant metastases, the age of the patient, and the extent of the tumor.…”

“…A number of large, retrospective studies show a significant reduction in the rates of disease recurrence (61,98,99,126) and cause-specific mortality (98,99,(126)(127)(128). However, other similar studies show no such benefit, at least among the majority of patients with papillary thyroid carcinoma, who are at the lowest risk for mortality (68,101,(128)(129)(130)(131). In those studies that show benefit, the advantage appears to be restricted to patients with larger tumors (Ͼ 1.5 cm), or with residual disease after surgery, while lower risk patients do not show evidence for benefit (68,98,132).…”

Controversies about Radioactive Iodine-131 Remnant Ablation in Low Risk Thyroid Cancers: Are We Near A Consensus?

“…In 1970's concept of using RAI for ablation got popularity and Mazzaferri and Young (1981) published 10 years follow-up data of 576 patients revealing efficacy of RAI in reducing mortality and recurrence. However, Hay et al (2002) presented data of 2444 patients treated during showing no significant impact of RAI upon mortality and tumor recurrence in low risk thyroid cancer patients. Despite of these conflicting findings from these retrospective studies, during this period in US, approximately 38% of patients with WDTC are reported to have received RAI ablation or therapy (Edwards et al, 2002).…”