Total thyroidectomy or thyroid lobectomy in patients with low-risk differentiated thyroid cancer: Surgical decision analysis of a controversy using amathematical model

There is a general consensus that total or near-total thyroidectomy is the optimal treatment for patients with high risk differentiated thyroid cancer (DTC), but the optimal extent of thyroidectomy in patients with low risk D TC continues to be controversial. To determine the optimal extent of thyroi dectomy in patients with low risk DTC, we used decision analysis to compare the trade-offs of total thyroidectomy (TT) to thyroid lobectomy (TL). The decision analysis model included the probabilities of thyroidectomy complic ations, risk of DTC recurrence, and death from DTC. This information was ob tained from the literature and from outcome data for patients with low risk DTC from our institution. In addition, the concept of utilities was used i n the analysis. To determine the utility of each health outcome state (thyr oidectomy complication, DTC recurrence, and DTC mortality for low risk pati ents) a survey was conducted. Overall, prospective patients viewed DTC recu rrence as less desirable than thyroidectomy complication. The utilities ass igned by the survey participants varied over a wide range, with 61.5% of th e individuals viewing the occurrence of a thyroidectomy complication as bet ter than DTC recurrence. At baseline utilities and probabilities, TT had a higher expected utility than TL. One-way sensitivity analysis varying the r ates of (1) thyroidectomy complication, (2) DTC recurrence, and (3) DTC mor tality over the possible range showed that complication from initial thyroi dectomy was the most important factor that determined the preferred extent of thyroidectomy. TL was the preferred surgical approach only if a complica tion rate of > 33:1, TT/TL complication rate ratio, was assumed. When no di fferences in DTC recurrence between the two approaches was assumed in the m odel, TL had a higher expected utility using the baseline utilities of thyr oidectomy complication and DTC mortality. The analysis indicates that TT in patients with low risk DTC is preferable to TL. However, TL is preferred i f (1) no difference in the DTC recurrence rate between the two approaches i s assumed, (2) a higher complication rate for TT is used (> 33 times higher ), or (3) the utility ratio of thyroidectomy complication to DTC recurrence is < 0.8 TL. We believe this decision analysis model provides an objective approach that others can use to select the optimal extent of thyroidectomy based on patient preference of health outcome states, institution-specific outcome data for DTC recurrence or mortality, and the surgeon-specific com plication rate.