Importance: Population-based genomic screening can facilitate early detection of medullary thyroid carcinoma (MTC) in patients with pathogenic/likely pathogenic (P/LP) RET variants.
Objective: To evaluate the clinical treatment and patient outcomes after identification of P/LP RET proto-oncogene variants associated with the risk of MTC via a population genomic screening program.
Design, setting, participants: This retrospective cross-sectional study was completed between June 1, 2016, and May 31, 2022, for a mean follow-up period of 22.4 months (range, 2-76 months). The study included patients who were identified as having P/LP RET variants through a population genomic screening program at a rural tertiary care center and who underwent thyroidectomy after results disclosure.
Main outcomes and measures: The outcomes of interest were preoperative evaluation and treatment-related outcomes. Measures included imaging and laboratory findings, extent of surgery, pathologic diagnosis, and staging.
Results: Seventy-five patients were identified as having P/LP RET variants exclusively through genomic screening. Twenty of these patients (27%; 11 women [55%] and 9 men [45%]; median age, 48 years [range, 22-73 years]) underwent total thyroidectomy; 13 of these patients (65%) also had a central neck dissection. No patients had clinically apparent disease at the time of surgery. Pathologic findings indicated MTC for 12 patients and papillary thyroid carcinoma in 2. Of patients with MTC, 10 had stage I disease, 1 had stage II disease, 1 had stage III disease, and none had stage IV disease. Based on postoperative surveillance imaging and laboratory results, no patient had evidence of recalcitrant disease.
Conclusions and relevance: In this cross-sectional study, all malignant neoplasms identified on surgical pathology were clinically occult, with surgical intervention based solely on the identification of the P/LP RET variant via population genomic screening. This finding suggests that genomic screening may provide opportunities for early detection and treatment of MTC, with the potential for improved patient outcomes.