Timing of Adjuvant Radioactive Iodine Therapy Does Not Affect Overall Survival in Low- and Intermediate-Risk Papillary Thyroid Carcinoma

Abstract

There is no consensus regarding the timing of adjuvant radioactive iodine therapy (RAI) therapy in low- and intermediate-risk papillary thyroid carcinoma (PTC). We analyzed the impact of adjuvant RAI on overall survival (OS) in low- and intermediate-risk PTC. The National Cancer Data Base was queried from 2004 to 2011 for pN0M0 PTC patients having near/subtotal or total thyroidectomy and adjuvant RAI. Tumors ≤1 cm with negative margins were low risk while 1.1- to 4-cm tumors with negative margins or ≤1 cm with microscopic margins were termed intermediate risk. RAI in ≤3 months and between 3 and 12 months was termed as early and delayed, respectively. Survival analysis was performed after adjusting for patient and tumor-related variables. There were 7,306 low-risk and 16,609 intermediate-risk patients. Seventeen per cent low-risk and 15 per cent intermediate-risk patients had delayed RAI. Kaplan-Meier analysis did not show a difference in OS for early versus delayed RAI administration in low- (10-year OS 94.5% vs 94%, P = 0.627) or intermediate-risk (10-year OS 95.3% vs 95.9%, P = 0.944) patients. In adjusted survival analysis, RAI timing did not affect OS in all patients (hazard ratios = 0.98, 95% confidence interval = 0.71–1.34, P = 0.887). In conclusion, the timing of postthyroidectomy adjuvant RAI therapy does not affect OS in low- or intermediate-risk PTC.

Delayed initial radioiodine therapy related to incomplete response in low‐ to intermediate‐risk differentiated thyroid cancer

“…Higashi et al have investigated the effects of delayed RAI therapy (more than 180 d) on OS in 198 metastatic patients with DTC and indicated that the risk of death was 4.22 times higher in metastatic patients with delayed RAI treatment. Other studies presented contrary conclusions, indicating that delayed RAI would not affect the OS in patients in all categories of TNM stage and ATA risk stratification . Tsirona et al demonstrated that the timing of RAI did not impact remission in limited numbers of low‐risk DTC.…”

“…Whether the initiating time will affect the clinical outcome of RAI treatment remains uncertain. Few clinical studies have focused on this issue with controversial conclusions . Higashi et al reported that delayed RAI therapy (>180 days after total thyroidectomy) may result in poor survival for DTC compared with early RAI therapy.…”

“…Higashi et al reported that delayed RAI therapy (>180 days after total thyroidectomy) may result in poor survival for DTC compared with early RAI therapy. Other authors claimed that the timing of RAI therapy would no impact the overall survival (OS) and disease‐free survival (DFS) . It is noteworthy that in these studies, clinical outcome was evaluated in terms of OS and DFS.…”

In properly selected patients with differentiated thyroid cancer, antithyroglobulin antibodies decline after thyroidectomy and their sole presence should not be an indication for radioiodine ablation

“…These findings confirm that, in properly selected patients with low or intermediate risk of recurrence, in whom the use of RAI is selective, the behavior of Tg and TgAb during follow-up can modulate the indication for RAI. Furthermore, previous studies have shown that in low-and intermediate-risk patients, the efficacy of RAI is preserved even if administered up to one year after surgery, giving the clinician enough time to thoroughly decide its indication (31)(32)(33).…”

The Diagnostic Role of Computed Tomography for ACR TI-RADS 4–5 Thyroid Nodules With Coarse Calcifications

“…In routine practice, the time for patients from finishing enhanced CT examination to starting RAI therapy is far more than 43 days. Moreover, the majority of studies showed that the timing of post-thyroidectomy initial RAI therapy did not affect the overall survival or long-term outcomes (33)(34)(35)(36)(37)(38). Therefore, RAI administration may be safely planned according to the logistics of the local health and the patient itself.…”