E D I T O R I A LCounterpoint

See reply to counterpoint on pages 403–4 andreferenced original article on pages 553–9, thisissue.

Address for reprints: Ashok R. Shaha, M.D., Headand Neck Service, Memorial Sloan-Kettering Can-cer Center, 1275 York Avenue, New York, NY10021.

Received October 23, 1997; accepted November4, 1997.

Thyroid CarcinomaImplications of Prognostic Factors

Ashok R. Shaha, M.D.

Head and Neck Service, Memorial Sloan-Kettering Cancer Center, New York, New York.

The article by Baudin et al. in this issue of Cancer1 is quite inter-esting and represents an experience with a large series at the

Gustave-Roussy Institute in France. However, the authors combinedlocal recurrence in the thyroid bed and regional lymph node metas-tasis as the sites of failure, and the statistical analysis was performedon various prognostic factors and sites of failure. In spite of thesecombined failure sites, the recurrence rate was quite low (3.9%),which was consistent with other series in the literature. It would bedifficult to conclude that the extent of surgery performed to treat aprimary thyroid tumor would have made a major impact on regionallymph node metastasis. If we excluded the regional node metastasis,local recurrence in the thyroid bed would be noted for only 4 of 281patients (less than 2%). The thyroid tumors in this series were smallerthan 1 cm in greatest dimension and were associated with excellentprognosis. In reported experiences with similar thyroid tumors atother institutions, survival has exceeded 99% with long term follow-up. It is interesting that eight of these patients had distant metastasisat initial presentation. It would be of interest to review their histologyto see whether these were truly well-differentiated, particularly pap-illary/follicular thyroid cancers, or if they belonged to the group ofpoorly differentiated thyroid carcinomas.

The findings for 189 of 281 cancers were incidental. Whenever anincidental thyroid carcinoma is found at the time of surgery and theopposite lobe is clinically normal, lobectomy and isthmectomy isgenerally considered quite satisfactory. The authors considered mul-tifocality a major prognostic factor. However, it is unclear from thearticle whether this multifocality was clinically evident macroscopicdisease in the other lobe or whether it was microscopic multifocality.Microscopic multifocality, known as ‘‘laboratory cancer,’’ has noprognostic bearing.

Thyroid carcinoma is generally considered to be associatedwith the best prognosis. However, it generates considerable con-troversy and discussion. Unfortunately, the controversy continues,as a result of different institutional practices and personal preju-dices. The recent understanding of the prognostic factors and riskgroup analysis is extremely important in analyzing any data onthyroid carcinoma. Survival for the low risk group with long termfollow-up exceeds 99%. The role of any adjuvant therapy for thisgroup of patients, including radioactive iodine, is an unsolvedquestion. Careful and close follow-up appears to be quite satisfac-tory for the truly low risk group. Mortality in the high risk group is

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definitely considerable, extending up to 45%. Thehigh risk group clearly needs aggressive surgery,adjuvant administration of radioactive iodine, andoccasionally external radiation therapy as indicated.

In this series of 281 patients with microcarcinoma(less than 1 cm) reported by Baudin et al., adjuvantradioactive iodine was used to treat 124 patients(44%), including 39% of the patients with incidentalthyroid carcinoma. This leads the reader to believethat there is a strong bias favoring the routine use ofradioactive iodine at the authors’ institution. Clearly,the aggressiveness of thyroid carcinoma should beappreciated based on prognostic factors and clinicalfindings of extrathyroidal extension, distant metasta-

ses, and poorly differentiated histology. Under thosecircumstances, adjuvant radioactive iodine ablationshould be considered; however, in other circum-stances, this may be overkill. The outcome in patientswith microcarcinoma is excellent, and the decisionsregarding the extent of treatment should be based onindividual, clinical, and pathologic findings, and risk-group analysis.

REFERENCE1. Baudin E, Travagli JP, Ropers J, Mancusi F, Bruno-Bossio G,

Caillou B, et al. Microcarcinoma of the thyroid gland: theGustave-Roussy Institute experience. Cancer 1998;83:553–9.

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