HIGHLY-SELECTED SPORADIC, APPARENTLY UNIFOCAL CN0 MTC MAY BENEFIT OF UNILATERAL SURGERY. A PROOF OF CONCEPT FROM A HIGH-VOLUME INSTITUTION rossi.leonardo.phd@gmail.com

 

HIGHLY-SELECTED SPORADIC, APPARENTLY UNIFOCAL CN0 MTC MAY BENEFIT OF UNILATERAL SURGERY. A PROOF OF CONCEPT FROM A HIGH-VOLUME INSTITUTION

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Italy

Oral only

This study aimed to evaluate the incidence of multifocality, bilaterality, and central compartment lymph node involvement (both ipsilateral and contralateral) in patients with apparently unifocal sporadic medullary thyroid carcinoma(sMTC) cN0.

Patients with sMTC cN0 were prospectively enrolled between February 2022 and September 2024. To confirm the sporadic form of MTC, the search for RET germline mutation was performed in all cases. All patients underwent total thyroidectomy with CCND. Ipsilateral and contralateral central compartment lymph nodes(LNs) were harvested separately for histopathological examination.

A total of 54 patients were included in the study. The median age was 60 years, with a female predominance of 55.6%. Pre-operative median calcitonin (CTN) levels were 112.5 µg/L. Median tumor size was 1.1 cm. Three patients(5.6%) presented with multifocal sMTC, but only one had bilateral sMTC(1.9%). The median number of central compartment LNs removed was 10. Twelve patients(22.2%) had lymph node metastasis(pN1), including 2 patients(3.7%) with lymph node metastases in both the ipsilateral- and contralateral-central compartments. All metastatic lymph nodes measured ≤ 5 mm. At multivariate analysis, no independent risk factor for lymph node metastasis was found among age(p=0.589), sex(p=0.069), CTN(p=0.953), tumor size(p=0.644) and desmoplasia > 20%(p=0.087).

Sporadic cN0 MTC harbors a unilateral disease in 94.4% of cases. Contralateral lymph node involvement in extremely rare in highly selected cases, although ipsilateral central compartment lymph node metastasis occur in 22.2% of cases. In this cohort of patients, unilateral surgery (hemithyroidectomy with ipsilateral CCND) may be the treatment of choice.