Modified dynamic risk stratification for predicting recurrence using the response to initial therapy in patients with differentiated thyroid carcinoma

Abstract

Objective: A new risk stratification system was proposed to estimate the risk of recurrence in patients with differentiated thyroid carcinoma (DTC) using the response to initial therapy. Here, we describe the modified dynamic risk stratification system, which takes into consideration the status of serum anti-Tg antibody (TgAb), and validate this system for assessing the risk of recurrence in patients with DTC. Patients and methods: Patients who underwent total thyroidectomy with radioiodine remnant ablation due to DTC between 2000 and 2005 were included. We classified patients into four groups based on the response to the initial therapy ('excellent', 'acceptable', 'biochemical incomplete', and 'structural incomplete' response). Results: The median follow-up period of 715 patients with DTC was 8 years. The response to initial therapy was an important risk predictor for recurrent/persistent DTC. The relative risks (95% CI) of recurrence were 16.5 (6.3-43.0) in the 'acceptable response ' group, 41.3 (15.4-110.8) in the 'biochemical incomplete response' group, and 281.2 (112.9-700.5) in the 'structural incomplete response' group compared with the 'excellent response' group (P!0.001, P!0.001, and P!0.001 respectively). The disease-free survival rate of the 'excellent response' group to initial therapy was 98.3% whereas that of the 'structural incomplete response' group was only 6.8%. Conclusions: Our study validates the usefulness of the modified dynamic risk stratification system including the status of serum TgAb for predicting recurrent/persistent disease in patients with DTC. Personalized risk assessment using the response to initial therapy could be useful for the follow-up and management of patients with DTC.

Dynamic risk stratification in the follow-up of thyroid cancer: what is still to be discovered in 2017?

“…Next, 6-24 months after an initial therapy, they were reclassified to one of the following category: excellent response, acceptable response, biochemical incomplete response and structural incomplete response: 61, 20, 7 and 12% of patients, with disease-free survival (DFS) rates of 98.3, 71.6, 54.2 and 6.8%, respectively. PVE value of this modified dynamic risk stratification was significantly higher than ATA and TNM risk stratification systems: 44.59% vs 12.14% and 8.68% respectively (Jeon et al 2014).…”

“…Korean authors evaluated dynamic risk stratification in a group of 715 DTC patients after total thyroidectomy and RAI ablation (Jeon et al 2014). The authors called their approach a 'modified dynamic risk stratification' because they focused also on the status of antiTg antibodies in their risk assessment.…”

“…The time, when the treatment response was evaluated varies across the studies (Table 3). In some papers the authors analyzed all clinical data obtained during first 2 years of follow-up to assess treatment response (Tuttle et al 2010, Momesso et al 2016, Park et al 2017, whereas the others carried out risk restratification in different single time points between 8 and 24 months after initial therapy (Castagna et al 2011, Jeon et al 2014, Kowalska et al 2016, Morosán et al 2016. One may ask the question which data are more accurate for risk restratification: these collected during the first 2 years of follow-up or those obtained during single assessment between 8 and 24 months after initial therapy?…”

“…The number of follow-up visits and diagnostic examinations may influence the diagnosis of cancer recurrence. Considering outcome variables, some of papers analyzed the percentage of patients with NED or persistent disease, recurrence rates, and the number of cancer-related deaths (Tuttle et al 2010, Castagna et al 2011, Kowalska et al 2016, Morosán et al 2016, Momesso et al 2016, Park et al 2017, whereas other studies performed PFS or DFS analyses , Jeon et al 2014, Tavarelli et al 2017) to compare the patients with different stages of initial stratification or treatment response. We have to be aware that important limitation of PFS or DFS is how closely patients are followed.…”

Early prognostic factors at the time of diagnosis of bone metastasis in patients with bone metastases of differentiated thyroid carcinoma

“…Moreover, caution must be exercised when interpreting the results of the initial RxWBS if the remnant thyroid tissues are relatively larger. The disease status after the initial treatment of DTC patients should therefore be reassessed, as shown by a previously reported dynamic risk stratification system (22,23). When considering these patients as RAI-avid, RAI avidity was found to be a significant prognostic factor in the 93 patients (data not shown).…”