AbstractThis study of 542 patients with follicular thyroid cancer, 366 patients with the
follicular variant and 1452 patients with the classical variant of papillary
thyroid cancer, and 819 patients with sporadic medullary thyroid cancer operated
at a tertiary referral center aimed to determine risk patterns of distant
metastasis for each tumor entity, which are ill-defined. On multivariable
logistic regression analyses, lymph node metastasis consistently emerged as an
independent risk factor of distant metastasis, yielding odds ratios (ORs) of 2.4
and 2.8 for follicular thyroid cancer and the follicular variant of papillary
thyroid cancer, and ORs of 5.9 and 6.4 for the classical variant of papillary
thyroid cancer and sporadic medullary thyroid cancer. Another independent risk
factor consistently associated with distant metastasis, most strongly in
follicular thyroid cancer and the follicular variant of papillary thyroid cancer
(OR 3.5 and 4.0), was patient age >60 years. Altogether, 2 distinct risk
patterns of distant metastasis were identified, which were modulated by other
cancer type-dependent risk factors: one with lymph node metastasis as leading
component (classical variant of papillary thyroid cancer and sporadic medullary
thyroid cancer), and another one with age as leading component (follicular
thyroid cancer and the follicular variant of papillary thyroid cancer). Distant
metastasis was exceptional in node-negative patients with sporadic medullary
thyroid cancer (1.7%) and the classical variant of papillary thyroid
cancer (1.4%), and infrequent in node-negative patients with the
follicular variant of papillary thyroid cancer (4.4%). These findings
delineate windows of opportunity for early surgical intervention before distant
metastasis has occurred.
Radioactive iodine therapy may not improve disease‐specific survival in follicular variant papillary thyroid cancer without distant metastasis: A propensity score‐matched analysis
