Background: Papillary thyroid carcinoma is the most common thyroid malignancy in the U.S. As many as half of patients with papillary carcinoma present with cervical lymph node metastases at the time of diagnosis. Metastatic disease involving cervical lymph node tissue has not historically been proven to correlate with a more aggressive course; however, distant metastases worsen prognosis.
Methods: Diagnostic fine-needle aspiration (FNA) smears from 26 primary and metastatic papillary carcinomas underwent Feulgen reaction and were studied by image analysis to determine DNA pattern, proliferation index, and the percentage of cells with DNA content >5C. The medical records of all the patients were reviewed for metastatic disease pattern and survival data. For metastatic pattern, two groups were defined: 1) confined to thyroid/local lymph node metastases/soft tissues of the neck involved by tumor, and 2) distant metastases.
Results: Among the 26 patients, 16 had "nonaggressive" DNA patterns described as diploid, abnormal diploid, or tetraploid, and 10 had "aggressive" DNA patterns described as aneuploid. Only 2 of the 16 patients in the "nonaggressive" DNA pattern group developed distant metastases, whereas 5 of the 10 patients in the aneuploid group developed distant metastatic disease. In addition, none of the 16 patients with "nonaggressive" DNA patterns died of disease, whereas 3 of the 10 individuals with DNA histograms interpreted as aneuploid did die of metastatic disease complications.
Conclusions: Aneuploidy identified by image analysis of FNA of papillary thyroid carcinoma is significantly associated with death from papillary carcinoma (log rank test, P=0.027).