Outcomes of Conversion Surgery for Patients With Low-Risk Papillary Thyroid Carcinoma.

Importance:The outcomes of patients with low-risk thyroid cancer who undergo surgery following a period of active surveillance (AS) are not well-defined. Objective:To evaluate surgical, pathologic, and oncologic outcomes among patients undergoing conversion surgery (CS) following AS for low-risk papillary thyroid carcinoma. Design, Setting, and Participants:In this cohort study, patients who underwent CS for disease progression were compared with patients who underwent CS without disease progression and with a propensity score-matched cohort of patients who underwent initial surgery (IS). The median (IQR) postsurgical follow-up time was 40.3 (18.0-59.0) months. Patients were treated at a quaternary cancer referral center in the United States. Exposures:Surgery. Main Outcomes and Measures:Surgical complications, pathologic characteristics, overall survival (OS), and recurrence-free survival (RFS). Results:Of 550 patients who underwent AS, 55 (10.0%) had CS, of whom 39 (7.1%) had surgery due to suspected disease progression (median [IQR] age, 48 [39-56] years; 32 [82.1%] female). There were no clinically meaningful differences in rates of surgical sequalae between the progression CS group (12 of 39 [30.7%]) and the nonprogression CS group (7 of 16 [43.8%]) (Cramer V, 0.2; 95% CI, 0.01-0.5). The 5-year OS was 100% (95% CI, 100%-100%) in both the disease-progression CS cohort and the IS cohort. Although the cohort of patients undergoing CS after disease progression was by definition a subset with more aggressive tumor behavior, no clinically meaningful differences were observed in the rates of regional recurrence (2 of 39 [5.1%] vs 0 of 39 patients with IS), local recurrence (0 patients), distant metastasis (0 patients), or disease-specific mortality (0 patients) when compared with the matched IS group. Five-year RFS rates were similar: 100% in the IS group and 86% (95% CI, 70%-100%) in the CS group. Conclusions and Relevance:In this cohort study, CS for suspected disease progression was associated with surgical and oncologic outcomes similar to IS, supporting the feasibility and safety of AS for patients with low-risk papillary thyroid carcinoma.