Endocrine Abstracts

Much controversy persists over aggressiveness of oncocytic thyroid carcinoma (OTC) and its optimal treatment. The study purpose was to determine prognostic factors for persistent or recurrent disease (PRD) and discuss therapeutic directions.

We reviewed the medical records of 81 consecutive patients with OTC among a total of 1729 (4.7%) epithelial thyroid cancers, operated from 1983 to 2003 in our center. Follow-up information was updated. Age ranged from 17 to 86 years (median, 52). Univariate and multivariate analysis were performed to determine prognostic factors for PRD and calculate disease-free survival (DFS).

With a median follow-up of 7.9 years, 62 (77%) patients never relapsed and had no residual tumor at last follow-up and 19 (23%) had persistent disease or experienced recurrence of their disease. With univariate analysis, ten variables were significantly associated with PRD: age ≥45, malignant solitary or dominant nodule, compressive symptoms, tumor size >40 mm, malignancy diagnosed intraoperatively, radical modified neck dissection performed following frozen section findings, major vascular invasion, moderate or poor differentiation, pT4 and synchronous distant metastases. With multivariate analysis, only pathological parameters were independently associated with PRD: major vascular invasion (OR=1.64), moderate or poor differentiation (OR =6.69) and pT4 (OR =2.66). Among the 19 patients with PRD, 5 patients died of thyroid cancer, 10 are alive with disease progression, 2 demonstrated decreasing thyroglobulin to iterative radioiodine treatment, and 2 were cured after reoperation.

Our findings suggest that pT4 tumor, moderate or poor differentiation and major vascular invasion independently predict higher risk of persistent or progressive disease and shorten DFS; their presence should prompt completion of thyroidectomy if needed and radioiodine adjuvant therapy to optimize follow-up. Residual disease should indicate further medical or surgical intervention in a curative effort, since selected patients may be cured or stabilized and long term survival can be expected.effort, since selected patients may be cured or stabilized and long term survival can be expected.