Prognostic factors in papillary thyroid cancer: an evaluation of 601 consecutive patients

Although papillary thyroid cancer (PTC) is among the most curable cancer types, it can be a distressing disease for those patients suffering from frequent recurrences or even distant metastases leading to death. Age over 45 years is the most important indicator of poor prognosis. Our aim was to evaluate markers which might predict the outcome of an individual patient better than does TNM classification alone.

Of 601 consecutive patients who underwent surgery for PTC, retrospectively we selected 36 patient pairs in which one recovered completely after primary surgery, and the other suffered from aggressive disease. Formalin-fixed, paraffin-embedded tumor samples from these 72 patients were analyzed by immunohistochemistry for COX-2, MMP-2, VEGF-C, Bcl-2, Ki-67, and p21 expression.

None of the markers we studied showed a superiority over TNM classification in selecting patients likely to progress to aggressive disease. However, the expression of COX-2 and VEGF-C seemed to be increased in patients over 45, which could explain the more aggressive behavior of these tumors. Moreover, we found that age over 45, tumor size over 4 cm, extrathyroidal extension of tumor, nodal metastases, distant metastases, and stage IV had an unfavorable effect on survival.