Background: Management of thyroid microcancer or occult well-differentiated thyroid cancer (OWDTC) is controversial. Our present study compared some clinical features of OWDTC and gross well-differentiated 10-mm thyroid carcinoma (GWDTC), which may offer a basis for treatment policy.
Methods: From 1964 to 2000, 1000 patients underwent thyroidectomy for thyroid cancer. We randomly selected 428 cases for study in which node sampling was carried out in 88% of GWDTC and 60% of OWDTC and who were demographically comparable. All data were obtained by chart review and analyzed by chi-square test.
Results: With the maximum limit of 10 mm for defining OWDTC, we found 113 such cases with a mean size of 6.1 mm and 315 GWDTC cases with a mean size of 27.6 mm. The incidence of metastatic nodal disease was 16.8% in OWDTC cases and 25.7% in GWDTC cases (P = .057). Distant metastases occurred in 1 of 113 (0.9%) cases of OWDTC and 11 of 315 (3.5%) cases of GWDTC (P = .149). After a mean follow-up time of 55.8 months, neck metastatic recurrent disease occurred in 3 of 113 (2.7%) cases of OWDTC and 7 of 315 (2.2%) cases of GWDTC (P = .770). OWDTC was found in 11.1% of the GWDTC group undergoing an operation. Multicentricity occurred in 31.9% of OWDTC cases and 35.9% of GWDTC cases (P = .447). No cause-specific death occurred.
Conclusions: One cannot be dogmatic in treatment of microcancer, but one is justified in extending similar treatment principles for OWDTC as in GWDTC, which in our center usually indicates near-total thyroidectomy and consideration for radioactive iodine ablation.