ANAPLASTIC THYROID-CARCINOMA - A RETROSPECTIVE CLINICAL AND IMMUNOHISTOCHEMICAL STUDY

We reviewed 34 patients with histologically proven anaplastic thyroid carcinoma, representing 3.1% of all thyroid carcinomas treated from 1970 to 1992 in our Institution. Mean age at diagnosis was 63.1+/-10.3 years. Initial treatment consisted of near total thyroidectomy in 14 patients, partial thyroidectomy in 6 and no more than a biopsy in 14. After surgery 11 patients received external radiotherapy associated with chemotherapy (R+C), 8 patients had only chemotherapy (C), and 11 patients had only radiotherapy (R). Two patients, both in the group treated with R+C, are still alive, with a survival from the diagnosis of 23 and 26 months, respectively. Mean survival of the group treated with R+C (16.1+/-8.2 months) was significantly higher than that of patients treated only with C (6.2+/-4.4 months; p<0.01) or only with R (5.1+/-2.6 months; p<0.0004). In the group treated with R+C, patients submitted to near total or partial thyroidectomy had a mean survival of 15.0+/-8.8 months, similar to that of patients who had only a biopsy (17.2+/-7.9 months), suggesting that the outcome was affected by post-surgical therapy rather than by surgery per se. Twenty-two tumors were also assayed by immunohistochemistry for p53 and PCNA expression. p53 was expressed in 16/22 (72.2%) cases, with no correlation with sex, age, presence of differentiated component or survival. Comparing tumors with <30% or >30% p53 positive cells a tendency to longer (but not significant) survival was found in tumors with lower p53 expression. PCNA was expressed in all cases, with a percentage of positive cells ranging from 15% to 90%, and was not correlated with sex, age, differentiation, or survival. A positive correlation was found between PCNA and p53 expression (r=0.58; p=0.0039). In conclusion, our data indicate that in anaplastic thyroid carcinoma the use of combined R+C has some advantages with respect to single therapy. As in other aggressive malignancies; p53 and PCNA expression is increased irrespective of the response to therapy or the outcome.