The Delayed Risk Stratification System in the Risk of Differentiated Thyroid Cancer Recurrence

Abstract

ContextThere has been a marked increase in the detection of differentiated thyroid carcinoma (DTC) over the past few years, which has improved the prognosis. However, it is necessary to adjust treatment and monitoring strategies relative to the risk of an unfavourable disease course.Materials and MethodsThis retrospective study examined data from 916 patients with DTC who received treatment at a single centre between 2000 and 2013. The utility of the American Thyroid Association (ATA) and the European Thyroid Association (ETA) recommended systems for early assessment of the risk of recurrent/persistent disease was compared with that of the recently recommended delayed risk stratification (DRS) system.ResultsThe PPV and NPV for the ATA (24.59% and 95.42%, respectively) and ETA (24.28% and 95.68%, respectively) were significantly lower than those for the DRS (56.76% and 98.5%, respectively) (p<0.0001). The proportion of variance for predicting the final outcome was 15.8% for ATA, 16.1% for ETA and 56.7% for the DRS. Recurrent disease was rare (1% of patients), and was nearly always identified in patients at intermediate/high risk according to the initial stratification (9/10 cases).ConclusionsThe DRS showed a better correlation with the risk of persistent disease than the early stratification systems and allows personalisation of follow-up. If clinicians plan to alter the intensity of surveillance, patients at intermediate/high risk according to the early stratification systems should remain within the specialized centers; however, low risk patients can be referred to endocrinologists or other appropriate practitioners for long-term follow-up, as these patients remained at low risk after risk re-stratification.

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

“…However, there is no information to which risk-group the patients with cancer-related death were classified. Similar to Castagna study, Kowalska et al (2016) calculated PPV, NPV and PVE. Their results were concordant with the data reported in Castagna et al (2011), where DRS showed the highest ability in a prediction of DTC outcomes, with PPV, NPV and PEV 56.8, 98.5 and 56.7%, respectively (Kowalska et al 2016).…”

“…Another paper, confirming the relevance of DRS, involved into a retrospective analysis a group of 916 DTC patients treated with total thyroidectomy and RAI ablation in a single institution between the years 2000 and 2013 24:11 (Kowalska et al 2016). Likewise, the patients underwent an initial staging according to ATA 2009 (Cooper et al 2009) and ETA 2006(Pacini et al 2006 guidelines and were restratified 9-12 months after primary treatment (DRS) on the basis of response criteria proposed in Momesso & Tuttle (2014) as having an excellent response, biochemical incomplete response, structural incomplete response or indeterminate response.…”

“…However, some papers, analyzed in this review, proposed the term 'DRS' (Castagna et al 2011, Kowalska et al 2016 probably in opposite to an 'initial risk stratification'. One should ask the question whether 'DRS' means exactly the same as 'dynamic risk stratification'.…”

“…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.…”