The Results of X-Ray Treatment in Undifferentiated Carcinoma of the Thyroid

Abstract

This is a presentation of 44 cases of undifferentiated carcinoma of the thyroid treated by 2-Mev radiation. Because of extensive invasion of the neck and mediastinum, surgical cure was not possible, since resections, if attempted, were incomplete. The pathologic findings in the entire group have been reviewed. Our interest in these patients has continued because of our present ability to treat them more vigorously with x-rays than was possible at the time of the last report from this clinic by Hare and Salzman (1) in 1950. In that report the tumors were divided into small-cell and giant-cell carcinomas and the five-year survival rate was 20 per cent. Since 1949 we have treated the majority of these patients with 2-Mev radiation and when possible have tried to give a minimum tissue dose of 4,800 r. In the earlier report the dosages were all in terms of air dose, ranging from 4,800 to 6,000 r (in air). For various reasons many patients in the present series did not receive 4,800 r, some because of their poor general condition and others because peripheral metastases became apparent during the treatment period. Three of the series were treated by Dr. Joseph Marks at the New England Deaconess Hospital, Boston, and 3 were treated outside of Boston. Our present treatment pattern has been to deliver a tissue dose of 175 r per day, five days a week, to the neck, supraclavicular areas, and the superior mediastinum, with a goal of 4,800 r in most and 6,000 r in some cases. Pathology Many of the specimens removed for histologic examination in these cases represented only biopsies or partial excisions. For this reason, an adequate and consistent evaluation of the gross features of the various types of undifferentiated carcinoma was not feasible. When sufficient tissue was available for gross study, the appearance generally was that of obvious carcinoma with evident invasion of adjacent structures. In some cases, the gross differential diagnosis included the possibility of chronic thyroiditis. Again, because so much of the material consisted only of biopsy specimens, an evaluation of the microscopic changes in those portions of the gland uninvolved by tumor was incomplete. Although many of the specimens microscopically showed chronic thyroiditis in addition to tumor, whether this was a pre-existing condition or the result of the presence of the neoplasm could not be determined. Histologically these tumors have in common an undifferentiated, solid growth pattern, with few or no elements of a follicular or papillary nature. Microscopically there are four major subgroups which are readily distinguishable from one another. In addition, mixtures of these undifferentiated subtypes or even follicular or papillary foci, or both, were sometimes seen; such cases were placed in a fifth category of “mixed” cancers.