Pennsylvania Has High Rate of Increase in Thyroid Cancer, Including Advanced and Larger Tumors
In a population-based study reported in JAMA Otolaryngology-Head & Neck Surgery, Bann et al found that the average annual percent increase in thyroid cancer incidence in Pennsylvania approaches twice that in the rest of the country. The incidence of thyroid cancer in the United States has more than tripled since the mid-1970s, and Pennsylvania has the highest rate in the country. It has been unclear whether or to what degree overdiagnosis may contribute to the observed increases.
The study involved data from the Surveillance Epidemiology and End Results 9 (SEER-9) registry (110,615 cases) and the Pennsylvania Cancer Registry (29,030 cases) from 1985 through 2009.
Annual Increase
The average annual increase in thyroid cancer in Pennsylvania was 7.1% per year (95% confidence interval [CI] = 6.3%–7.9%) vs 4.2% per year (95% CI = 3.7%–4.7%) in the rest of the country (P < .01), with the trends in age-related incidence being significantly different (P < .001).
Increased Incidence of Advanced and Large Tumors
In Pennsylvania, the annual change was 7.6% in females vs 6.1% in males (P < .01), with trend analysis indicating that incidence may be increasing more rapidly in black vs white females (8.6% vs 7.6% per year, P = .60, but P < .005 in trend analysis). There have been increases in rates of tumors with both regional (7.0% per year) and distant spread (1.1% per year; P < .05) and in rates of tumors that were both 2 to 4 cm (7.1% per year) and > 4 cm (6.4% per year; P < .05) at diagnosis.
The investigators concluded: “The incidence of thyroid cancer is rising at a faster rate in Pennsylvania than in the rest of the nation, as is the rate of tumors that are larger and higher stage at diagnosis. These findings suggest that rising disease burden has contributed to the increased incidence of thyroid cancer. Etiologic factors promoting the rise in thyroid cancer in Pennsylvania must be investigated and may provide insight into the drivers of the national increase in thyroid cancer.”
David Goldenberg, MD, of Penn State College of Medicine, is the corresponding author for the JAMA Otolaryngology-Head & Neck Surgery article.
The study was supported by a National Cancer Institute grant.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
