11/04/2021
By Jessica Burkhamer

The Zuckerberg College of Health Sciences, Department of Public Health, invites you to attend a doctoral dissertation defense by Jessica Burkhamer on “Long-Term Trends of Thyroid and Other Cancers in Adolescents and Young Adults.”

Candidate Name: Jessica Burkhamer
Defense Date: Thursday, Nov. 18, 2021
Time: 2 to 4 p.m.
Location: Via Zoom meeting. Those interested in attending should contact Jessica_Burkhamer@student.uml.edu at least 24 hours prior to the defense to request access to the meeting.

Advisor: David Kriebel, Department of Public Health, University of Massachusetts Lowell

Committee Members

  • Leland Ackerson, Department of Public Health, UMass Lowell
  • Richard Clapp, Professor Emeritus, Public Health, Boston University and Senior Research Associate, Lowell Center for Sustainable Production, UMass Lowell

Brief Abstract: Cancer incidence is increasing in adolescents (“teens”) and young adults (AYAs). In particular, thyroid cancer is increasing fastest in this group compared with other ages. Although tremendous advances in cancer treatment have dramatically improved the survivability of cancer, even when “cured” cancer has devastating long-term effects including second malignancies and infertility. The causes of the increases are poorly understood but studying incidence patterns and trends may produce insights into etiology and suggest opportunities for prevention. However, with the exception of a small but growing body of research, study of cancer in AYAs has been relatively neglected in the US. The focus of cancer research has been on children and adults and research on cancer in teens and young adults has not kept pace.

Using data from the US National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program, we described trends of cancer incidence among teens (15- to 19-year-olds). We reviewed and summarized incidence patterns for histologic cancer groups and the most frequently diagnosed sites of cancer among teens during 2008-2012 reported by the SEER Cancer Statistics Review. We calculated annual incidence rates for the years 1975-2012 and used linear regression analysis to evaluate trends and calculate rates of change. The biggest annual incidence increases occurred in non-Hodgkin lymphoma (NHL) (2.16% females; 1.38% males), thyroid cancer (2.12% females; 1.59% males), acute myeloid leukemia (AML) (1.73% females) and testicular cancer (1.55% males). Incidence rates for most histologic groups and sites showed steady long term increases over the 38 years of data.

Thyroid cancer is increasing among all ages but is increasing the fastest among teens and is the second most common cancer among females aged 15-39 years in the US. Some of the increased incidence has been shown to be due to overdiagnosis; however, it probable that overdiagnosis is not the only cause and changes in prevalence of established risk factors for thyroid cancer are unlikely to explain the increases. Another striking characteristic of thyroid cancer is that it affects females at much higher rates than males. The ratio of female to male thyroid cancer incidence changes with age, peaking at about 5 to 1 among AYAs aged 15-39 years. To generate hypotheses about reasons for thyroid cancer increases and explore factors driving the heavily skewed gender ratio, thyroid cancer patterns and trends were explored using multilevel multivariate Poisson regression analysis. The results of this work suggest that health care access, and thus overdiagnosis, do not fully explain increases or the skewed gender ratio. The gender ratio and annual increases were both largest in the age group closest to puberty (15-19 years), providing evidence that female reproductive hormones may influence thyroid cancer risk.