Early Detection May Be Reason for More Thyroid Cancer
Most of increase over past 30 years may be due to detection of small papillary tumors
TUESDAY, May 9 (HealthDay News) -- The incidence of thyroid cancer has increased in the United States over the past 30 years, though this appears to be due to the increased detection of small papillary cancers, according to a study in the May 10 issue of the Journal of the American Medical Association.
Louise Davies, M.D., and H. Gilbert Welch, M.D., of Dartmouth Medical School in Hanover, N.H., examined thyroid cancer incidence, histology, size distribution and mortality in the United States from 1973 to 2002 using data from the National Cancer Institute's Surveillance, Epidemiology, and End Results program and the National Vital Statistics System.
While mortality from thyroid cancer remained stable, the incidence of thyroid cancer increased 2.4-fold from 3.6 to 8.7 per 100,000, which may be almost entirely attributable to an increase in the incidence of papillary thyroid cancers. Between 1988 and 2002, 49 percent of the increase consisted of tumors 1 cm or smaller and 87 percent consisted of tumors 2 cm or smaller.
"The increasing incidence of thyroid cancer in the United States is predominantly due to the increased detection of small papillary cancers," the authors conclude. "These trends, combined with the known existence of a substantial reservoir of subclinical cancer and stable overall mortality, suggest that increasing incidence reflects increased detection of subclinical disease, not an increase in the true occurrence of thyroid cancer."