Numerous prognostic factors have been studied for survival in patients with papillary thyroid carcinoma (PTC), although there are few multivariate studies that include the histological variety of PTC.
There are prognostic factors that influence survival in a series of patients with PTC, including the histological variety, and a new prognostic index (PI) for survival can be formulated by accounting for these factors.
A retrospective study.
A university hospital department of surgery.
Between January 1970 and December 1995, 200 patients undergoing surgery for PTC were observed (mean follow-up, 8 years).
Main Outcome Measures
A univariate analysis was done for survival rates using the Kaplan-Meier estimation method. The possible prognostic factors were evaluated using a multivariate analysis according to the Cox model. We formulated a PI and defined 3 risk groups (low, medium, and high) for mortality.
Of the 200 patients, 175 (87.5%) are still alive. Of the 25 deaths, 19 (9.5%) were due to the tumor. The survival was 97.5% at 1 year, 92.8% at 5, 89.5% at 10, and 83.9% at 15 and 20 years. The prognostic factors obtained after the multivariate analysis were age, tumor size, extrathyroid spread, and histological variant of the PTC. The PI is calculated as follows: PI = (2 × size) +(6 × spread) + (2 × variant) + (3 × age). As for the risk groups, the low-risk group showed a mortality of 0%; the medium-risk group, 17.1%; and the high-risk group, 76.5%.
The histological variety of PTC has prognostic value for survival in patients with PTC. As risk factors for PTC mortality, we consider an age of 50 years or older, a tumor larger than 4 cm, the existence of extrathyroid spread, and a certain histological subtype of PTC. With these risk factors, it is possible to formulate a PI and classify patients into low-, medium-, and high-risk groups for mortality.