Chatal J-F et al. (2006) Survival improvement in patients with medullary thyroid carcinoma who undergo pretargeted anti-carcinoembryonic-antigen radioimmunotherapy: a collaborative study with the French Endocrine Tumor Group. J Clin Oncol 24: 1705–1711

At present, there is no effective therapy for the treatment of metastatic medullary thyroid carcinoma (MTC). In two previous studies, pretargeted radioimmunotherapy—in which a bispecific antibody that localizes to carcinoembryonic-antigen-expressing carcinoma tissue, then binds a 131I-labeled bivalent hapten that is administered later—resulted in disease stabilization in ∼50% of treated patients who were followed up for up to 6 years after treatment. Chatal et al. compared the overall survival of 29 of these treated patients with that of 39 untreated patients with MTC.

A trend was noted for prolonged survival in treated patients, but did not reach statistical significance (P = 0.059). Among high-risk patients (patients with a serum calcitonin doubling time <2 years), however, treated patients survived significantly longer than untreated patients (median survival 110 months versus 61 months, P <0.03). Biologic response to treatment, defined as a >100% increase in pretherapy calcitonin doubling time, was also associated with longer survival. The mean survival of patients who responded (n = 9) was 159 months, compared with 109 months for those who did not respond (n = 10) and 64 months for untreated patients (P = 0.035 and P = 0.01, respectively). Unexpectedly, treatment resulted in high-grade hematologic toxicity in several patients.

These results indicate that pretargeted radioimmunotherapy is a promising treatment for high-risk patients with metastatic MTC.