Minimal extrathyroid extension ups recurrence risk in differentiated thyroid cancer
The risk of recurrence for differentiated thyroid cancer (DTC) escalates in patients with minimal extrathyroid extension (mETE), but the absolute increase in risk is small, according to a recent study.
Additionally, the risk is within the low-risk of recurrence category at 3.5 percent in patients without lymph node involvement (N0 disease). mETE confers no effect on disease-related mortality and should not change tumour stage.
The authors performed a meta-analysis of controlled trials comparing DTC patients with and without mETE to examine the impact of mETE on patient outcomes. A total of 13 retrospective studies including 23,816 patients met the inclusion criteria, with a median follow-up of 86 months.
In patients with N0 disease, mETE correlated with increased risk of recurrence (seven studies: odds ratio [OR], 1.73; 95 percent CI, 1.03–2.92). The absolute risk of recurrence was 2.2 percent and 3.5 percent in patients without and with mETE, respectively (p=0.04).
Studies involving patients with and without lymph node involvement showed mETE to be associated with a significantly higher risk of recurrence (eight studies: OR, 1.82; 1.14–2.91). The absolute risk of recurrence was 6.2 percent and 7 percent in patients without and with mETE, respectively (p=0.01).
mETE had nonsignificant impact (OR, 2.40; 0.95–6.03) in patients with micropapillary carcinoma, while no impact was seen on disease-related mortality (eight studies: OR, 0.5; 0.11–2.21).
“mETE in patients with DTC was defined as an intermediate risk feature in the 2015 American Thyroid Association guidelines. However, controversy persists as several studies suggested mETE has little effect on disease outcome,” the authors said.