Thyroid carcinoma

The article by Baudin et al. in this issue of Cancer is quite interesting and represents an experience with a large series at the Gustave-Roussy Institute in France. However, the authors combined local recurrence in the thyroid bed and regional lymph node metastasis as the sites of failure, and the statistical analysis was performed on various prognostic factors and sites of failure. In spite of these combined failure sites, the recurrence rate was quite low (3.9%), which was consistent with other series in the literature. It would be difficult to conclude that the extent of surgery performed to treat a primary thyroid tumor would have made a major impact on regional lymph node metastasis. If we excluded the regional node metastasis, local recurrence in the thyroid bed would be noted for only 4 of 281 patients (less than 2%). The thyroid tumors in this series were smaller than 1 cm in greatest dimension and were associated with excellent prognosis. In reported experiences with similar thyroid tumors at other institutions, survival has exceeded 99% with long term followup. It is interesting that eight of these patients had distant metastasis at initial presentation. It would be of interest to review their histology to see whether these were truly well-differentiated, particularly papillary/follicular thyroid cancers, or if they belonged to the group of poorly differentiated thyroid carcinomas. The findings for 189 of 281 cancers were incidental. Whenever an incidental thyroid carcinoma is found at the time of surgery and the opposite lobe is clinically normal, lobectomy and isthmectomy is generally considered quite satisfactory. The authors considered multifocality a major prognostic factor. However, it is unclear from the article whether this multifocality was clinically evident macroscopic disease in the other lobe or whether it was microscopic multifocality. Microscopic multifocality, known as ‘‘laboratory cancer,’’ has no prognostic bearing. Thyroid carcinoma is generally considered to be associated with the best prognosis. However, it generates considerable controversy and discussion. Unfortunately, the controversy continues, as a result of different institutional practices and personal prejudices. The recent understanding of the prognostic factors and risk group analysis is extremely important in analyzing any data on thyroid carcinoma. Survival for the low risk group with long term follow-up exceeds 99%. The role of any adjuvant therapy for this group of patients, including radioactive iodine, is an unsolved question. Careful and close follow-up appears to be quite satisfactory for the truly low risk group. Mortality in the high risk group is 401