Impact of the number of intermediate risk factors on outcome of papillary thyroid cancer.

PURPOSE

The 2015 American Thyroid Association risk stratification system (2015-RSS) is used to assess the tumor recurrence rate and guide the initial treatment. At the current moment, patients with one or multiple intermediate risk factors (IRF) have the same treatment. This study was conducted to evaluate the impact of the number of IRF characteristics on tumor persistence or recurrence rates.

METHODS

Patients with intermediate risk papillary thyroid cancer (PTC) were selected and analyzed, furthermore, they were divided into two subgroups, one with 1-2 IRF and another with ≥3 IRF. Those data were analyzed in relation to response to therapy at the end of the first year and in last appointment, time to reach non evidence of disease (NED) state and time in NED state.

RESULTS

A total of 257 patients were evaluated. Extrathyroidal invasion, vascular invasion, the total number of IRF and the subgroup of ≥3 IRF were associated with non-excellent response in last consultation; IRF lymph node metastasis was associated with non-excellent response in the first year and in last appointment and prolonged time in NED state; vascular invasion was associated with a shorter time in NED state; total number of IRF and aggressive histology were related to delay in the achievement of NED state.

CONCLUSIONS

Higher number of IRF was a predictive factor of non-excellent response in the last visit and was associated with longer time to reach the NED state. Those data suggest a benefit from closer follow-up and more intensive treatment in these patients.