A Comparison of Outcomes in Medullary Thyroid Carcinoma Patients With and Without a Preoperative Diagnosis: A Multicenter Retrospective Cohort Study

• Published in: Thyroid (New York, N.Y.) Vol. 33; no. 5; p. 578
• Main Authors: Oleinikov, Kira, Yaakov, Eden, Mizrachi, Aviram, Hirsch, Dania, Hirshoren, Nir, Bachar, Gideon, Robenshtok, Eyal, Benbassat, Carlos, Atlan, Karin, Mizrahi, Ido, Nisman, Benjamin, Twito, Orit, Grozinsky-Glasberg, Simona, Mazeh, Haggi
• Format: Journal Article
• Language: English
• Published: United States 01.05.2023
• Subjects: Adenocarcinoma, Follicular - surgery; Adult; Aged; Carcinoma, Medullary - diagnosis; Carcinoma, Medullary - surgery; Cohort Studies; Female; Humans; Male; Middle Aged; Retrospective Studies; Thyroid Neoplasms - diagnosis; Thyroid Neoplasms - pathology; Thyroid Neoplasms - surgery; Thyroidectomy; medullary thyroid carcinoma; preoperative diagnosis; FNAC
• ISSN: 1557-9077
• DOI: 10.1089/thy.2022.0424

Cytological limitations pose a challenge to preoperative diagnosis of medullary thyroid carcinoma (MTC) and therefore, a significant subset of patients is only diagnosed postoperatively. The objective of this study was to investigate the impact of knowledge of a preoperative MTC diagnosis on disease management and outcomes. Multicenter, retrospective, cohort study of MTC patients treated in Israel from January 2000 to June 2021. We compared cohorts of patients according to the presence or absence of a preoperative MTC diagnosis. Ninety-four patients with histologically confirmed MTC were included (mean age 56.2 ± 14.3 years, 43% males). Fifty-three patients (56%) had a preoperative MTC diagnosis (preop-Dx group), and 41 (44%) were confirmed only postoperatively (no-Dx group). The extent of surgical resection, including completion procedures, was as follows: total thyroidectomy in 83% versus 100% (  = 0.002), central lymph node dissection (LND) in 46% versus 98% (  < 0.001), ipsilateral lateral LND in 36% versus 79% (  < 0.001), and contralateral lateral LND in 17% versus 28% (NS), in the no-Dx versus the preop-Dx group, respectively. Pathology confirmed a smaller median tumor size of 16 ± 17.4 mm versus 23 ± 14.0 mm (  = 0.09), a higher proportion of micro-MTC (size ≤10 mm) 32% versus 15% (  = 0.03), and a higher rate of co-occurrence of follicular cell-derived carcinoma 24% versus 4% (  = 0.003), in the no-Dx compared to the preop-Dx group, respectively. The rates of extrathyroidal and extranodal tumor extension were not significantly different between the groups. At the last follow-up, the biochemical cure was attained in 55% [CI 0.38-0.71] compared to 64% [CI 0.50-0.77] of the no-Dx and the preop-Dx group, respectively (  = 0.41). After the exclusion of patients with micro-MTC, biochemical cure was more commonly achieved in the preop-Dx group (33% [CI 0.14-0.52] vs. 62% [CI 0.46-0.77],  = 0.04). Preop-Dx patients had improved overall survival compared to the no-Dx group (log-rank  = 0.04) over a median follow-up of 82 months (interquartile range [IQR] 30-153). Preoperatively, the diagnosis of MTC is often missed. An accurate preoperative diagnosis of MTC may enable guideline-concordant surgical treatment and ultimately contribute to an overall survival benefit in MTC patients.