VANCOUVER — Anaplastic thyroid cancer patients under age 60 at diagnosis or who have only intrathyroidal tumor are more likely to escape the generally extremely poor prognosis of this malignancy, Electron Kebebew, M.D., said at the annual meeting of the American Thyroid Association.
Aggressive multimodal therapy featuring surgical resection plus electron beam radiation appears to result in improved survival, added Dr. Kebebew of the University of California at San Francisco.
Anaplastic thyroid cancer is one of the most aggressive of all human malignancies. It makes up fewer than 2% of cases of thyroid cancer but accounts for the majority of deaths.
The use of aggressive multimodal therapy in patients with anaplastic thyroid cancer is controversial. Although it is advocated by some experts, there are scant supporting data in the literature. To shed additional light on the subject, Dr. Kebebew turned to the National Cancer Institute's Surveillance, Epidemiology, and End Results database, where he obtained detailed data on 516 affected patients gleaned from 12 population-based cancer registries. This cohort constitutes one of the largest groups of anaplastic thyroid cancer patients ever studied.
The study population included 345 women. Their mean age at diagnosis was 70.3 years. Eight percent had intrathyroidal tumor only, 38% had regional disease, and the remainder had distant metastases. For 10% of patients, anaplastic thyroid cancer wasn't their first primary cancer.
Roughly one-half of patients underwent surgical resection of their primary tumor; 59% of patients received electron-beam radiation. Six-month cause-specific mortality was 68.4%. One-year mortality was 80.7%. “That was not surprising. What was surprising was that nearly 6% of patients survived more than 10 years,” Dr. Kebebew observed.
In a multivariate analysis, age younger than 60 years, local disease, and combination therapy with resection plus electron-beam radiation were independent predictors of improved survival.