In the literature, the incidence of thyroid cancer presenting as thyroid nodules are variable range from 1.7 to 28.4%. One of the popular method for diagnosis of thyroid cancer is a fine needle aspiration cytology but has a false negative rate up
to
10%. The delayed operation of thyroid cancer due to misdiagnosis as a benign thyroid nodules are found occasionally. A clinical analysis was made on the 850 cases of thyroid nodules which were operated from September 1983 to December 1990 at the
Department of Surgery, Guro Hospital, Medical College of Korea University. Among the 850 cases, 182 cases(21.4%) were diagnosed as cancer postoperatively. In a total of 182 cancer cases were diagnosed as benign preoperatively by the clinical
impression
and fine needle aspiration cytology. Statistical analysis of the risk factors of malignancy was evaluated with chi square test by statistic software package "SAS/PROC FREQ".
@ES The obtained results are as follows:
@EN 1) Among the 850 cases of operated thyroid nodules, 715 cases were diagnosed as benign and 135 cases as malignant preoperatively. But 47 cases among the 715 cases(6.6%) were revealed cancer after the operation.
2) The cancer incidence according to age and sex distribution in 850 cases of thyroid nodules were as the following; The malignancy rate of male above 60(53%, 10/19) was higher than that of below 60(23%, 29/128)(P=0.05). Also the 715 cases which
was
diagnosed as benign preoperatively were shown similar results-above 60 aged male was 25%93/12) which was much higher than below 60 aged male(0.1%, 1/101)(P=0.0002). In the female, the cases with the age of 30 or above has statistically
significant
results of higher malignancy rate(22.7%, 115/506) than below 30 aged females914.2%, 28/197)(P=0.037).
3) There was no statistical difference in the cancer incidence between the two group of above 1.5 cm sized nodule, 74.5%(35/47) in one group which was malignant preoperatively and 82.2%(111/135) in other group which was benign preoperatively
4) There was no statistical difference between the two group in the cancer incidence of thyroid nodule which had shown concomitant euthyroid state in TFT with cold nodule in thyroid scan that were 83.7%982/98), 91.7%(22/24) each other.
5) There was no statical difference between the two group in the cancer in the cancer incidence of single hard nodule that were 49.6%(67/135), 46.8%(22/47) each other.
In the conclusion, we believe that the thyroid nodule of above 60 aged male, bigger than 1.5 cm size of tumor, euthyroid, cold and solitary hard nodule in the thyroid scaning needs aggressive evaluation for cancer in spite of negative fine needle
aspiration cytology.
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