INTRODUCTION: The incidence of thyroid cancer (TC) is increasing in adolescent and young adult (AYA) patients. Many types of cancer diagnosed in the AYA age group differ significantly in clinical and pathological features from cancers diagnosed in older age groups, but data on TC are limited. Our aim was to compare the clinicopathological features of TC in AYAs and adults ≥40 years old.
METHODS: In total, 1013 patients with TC were retrospectively reviewed. Thyroid functions, ultrasonographic features of malignant nodules, cytological and histopathological findings, and recurrence and persistence rates were compared in AYAs and patients ≥40 years old.
RESULTS: There were 229 (22.61%) AYA patients and 784 (77.39%) patients ≥40 age group. Of all cancer types, 93.12% in AYAs and 93.58% in the ≥40 age group were papillary thyroid cancer (PTC) (p=0.772). Multifocal thyroid tumors were detected in 62 (27.07%) of AYAs and 269 (34.31%) of the ≥40 age group (p=0.039). Incidental thyroid tumors were detected in 113 (37.05%) of AYAs and 583 (52.01%) of the ≥40 age group (p<0.01). The extrathyroidal extension (ETE) was detected in 9.61% of AYAs and 16.33% of patients ≥40 years old (p=0.012). Capsular and vascular invasion, lymph node metastasis, distant metastasis, persistence, and recurrence rates were similar.
DISCUSSION AND CONCLUSION: There was no increase in the aggressive clinical and pathological features of TC in AYAs. ETE, multifocal tumors and incidental tumors were less common in AYAs than in patients ≥40 years old. PTC is the most common type in both groups, while the follicular variant PTC (FVPTC) subtype is increased in AYAs. Thyroid nodules should be carefully evaluated in AYAs, and diagnostic procedures should be recommended without delay. However, when TC is diagnosed in AYAs, the overtreatment potential of a disease with an excellent prognosis should also be considered.