The Journal of the Arkansas Medical Society Med Journal Dec 2019 | Page 18

Thyroid Cancer in Arkansas: Facts & Figures
Figure 3: Figure
Thyroid
Cancer, SEER 2000 Stage at Diagnosis, by Race and Sex,
3: Thyroid Cancer, SEER 2000 Stage at Diagnosis, by Race and Sex,
Arkanasas, 2001 -2015
Arkanasas, 2001 - 2015
90
80
70
76.8
69.7
74.5
60
63.2
Black, F
Black, M
50
30
20.4
20
White, M
24.3 23.4
10
0
White, F
33.0
40
2.8
Early Stage
Late Stage
6.1
2.2 3.8
Unstaged
Stage at Diagnosis
Note: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention and National Cancer
Note:
U.S. Department
Health and
Centers
Disease Control
and Prevention
National
Cancer
Institute.
National Program
Institute.
National of Program
of Human
Cancer Services,
Registries
and for
Surveillance,
Epidemiology,
and and
End
Results
SEER*Stat
Database:
of Cancer Registries and Surveillance, Epidemiology, and End Results SEER*Stat Database: NPCR and SEER Incidence – U.S. Cancer Statistics 2001–
NPCR
and
SEER
Incidence
–
U.S.
Cancer
Statistics
2001–2015
Public
Use
Research
Database,
based
on
November
2017
2015 Public Use Research Database, based on November 2017 submission. Cases were identified based on “Site and Morphology Site
Recode
ICD-O-3/WHO
2008
= Thyroid”.
Accessed at based
www.cdc.gov/cancer/npcr/public-use.
on 10/03/2018. 2008 = Thyroid”. Accessed at
submission.
Cases
were identified
on “Site and Morphology Site Retrieved
Recode ICD-O-3/WHO
www.cdc.gov/cancer/npcr/public-use. Retrieved on 10/03/2018.
Mortality
estimates 53,990 new cases of thyroid cancer will
During the years 2001-2015, 69.7% of the
be diagnosed
in the to U.S.
2018 (Siegel,
Miller, during
& total
black males
were
diagnosed
Comparable
the in national
average,
the cases
years among
2001 through
2015,
there
were a
Jemal, 2018). Among the new cases, an estimated at the early stage of disease, and the remaining
40,900
will deaths
occur in from
women
and 13,090
oc- 30.3%
cases were
diagnosed
in the
late deaths
stage
total
of 233
thyroid
cancer will
in Arkansas;
103 of deaths
among
men and
133
cur in men (Siegel et al., 2018). The combined-year of disease or were not staged (Figure 3). Of the
among
females incidence
(CDC, 2017).
for age, four
the race
combined
mortality
rate males
from 2001
age-adjusted
rate After
from adjusting
2001 through
and sex year
categories,
white
were
2015 in the U.S. was 12.2 per 100,000 (CDC, most likely diagnosed with late stage thyroid can-
through
was 0.5 age-adjusted
per 100,000 incidence
in Arkansas
2017).
2016). 2015
The national
rate (CDC,
cer;
while black males fared worse in regards to
was 7.9 per 100,000 and 14.5 per 100,000 in 2001 unstaged, followed by white males (Figure 3).
Risk Factors
and 2015, respectively (Figure 1).
Mortality
Other than
radiation with
in childhood through adolescence, none of the
According
to exposure
the NPCR to calculated
Comparable to the national average, during
SEER*Stat, from 2001 through 2015 there were a
the
years
2001 through 2015, there were a total
established
risk incident
factors, cases
such of
as thyroid
age, female
total of 3,841
cancer sex,
re- inherited genetic mutations, and family history,
of 233 deaths from thyroid cancer in Arkansas;
ported in Arkansas (ACCR, 2018). The age-adjusted
for developing thyroid cancer is modifiable (ACS, 2017,
ATA, 2016,
NCI,
2018).
103 deaths
among
men
and 133 deaths among
incidence rate in Arkansas was 5.1 per 100,000
females (CDC, 2017). After adjusting for age, the
and 13.7 per 100,000 in 2001 and 2015, respec-
Screening
combined year mortality rate from 2001 through
tively (Figure 1). The combined year age-adjusted
2015 was 0.5 per 100,000 in Arkansas (CDC,
incidence
Arkansas during
the years
The rate
U.S. in Preventative
Services
Task 2001
Force (USPSTF) recommends against screening for
2017).
through 2015 was 8.6 per 100,000 (ACCR, 2018).
thyroid
cancer
among
adults
who cases
are asymptomatic
(USPSTF, 2017). The USPSTF concludes with
The ACS
estimates
that
380 new
of thyroid
Risk Factors
cancer will be diagnosed in Arkansas in 2018 (ACS,
Other than exposure to radiation in childhood
2018). The statistically significant average annual
through adolescence, none of the established risk
percent change (AAPC) in the incidence of thyroid
factors, such as age, female sex, inherited genetic
cancer was 7.0% (p<0.05) and 4.5% (p<0.05) in
mutations, and family history, for developing thy-
the US and Arkansas, respectively (Figure 1).
roid cancer is modifiable (ACS, 2017, ATA, 2016,
According to 2018 estimates, thyroid cancer NCI, 2018).
is the fifth most common cancer among females
(NCI, 2018). Contrarily, it is not among the ten lead- Screening
ing cancer sites among males (NCI, 2018). For
The U.S. Preventative Services Task Force
reasons currently unknown, thyroid cancer occurs (USPSTF) recommends against screening for thy-
approximately 2.6 times more often in females than roid cancer among adults who are asymptomatic
in males, and this gender disparity persists across (USPSTF, 2017). The USPSTF concludes with suf-
racial groups. After adjusting for age, the combined- ficient certainty that screening for thyroid cancer
year incidence rate for white and black females was in asymptomatic adults is potentially harmful or
nearly three times (Risk Ratio [RR]: 2.6 and 3.4) that has no net benefit (USPSTF, 2017).
of white and black males, respectively (Figure 2).
138 • THE JOURNAL OF THE ARKANSAS MEDICAL SOCIETY
Discussion
Incidence-Mortality Discrepancy
Thyroid cancer is the most rapidly increasing
malignancy in the U.S. (ACS, 2018). Some describe
the trend as an epidemic of incidence. The age-
adjusted incidence rate of thyroid cancer has been
steadily increasing for nearly two decades (CDC,
2016) (Figure 1). While the incidence rate was in-
creasing, the rate of mortality from thyroid cancer
remained stable (CDC, 2016). This incidence-mor-
tality rate discrepancy is suggestive of enhanced
disease detection and overdiagnosis. However, the
steadily increasing trend in the incidence of thyroid
cancer should be monitored. There are a few rea-
sons that can explain the alarming rapidly increased
trend in thyroid cancer incidence rate observed:
Overdiagnosis
In 1973, significant developments in the capa-
bilities of medical ultrasonography led to a rise in
the detection of thyroid cancer, some of which in-
cluded cases of overdiagnosis (ACS, 2018). Overdi-
agnosis is when an asymptomatic cancer is identi-
fied through diagnostic criteria, but the malignancy
is neither invasive nor so fast-growing that it would
be life-threatening (NCI & Kramer, 2018). While in-
cidence rates increased for malignant nodules of
all sizes, the increases were most rapid for smaller
sizes (Enewold et al., 2009). During the years 1975
to 2009, 87% of the increase in incidence can be
attributed to papillary thyroid tumors that measured
2 centimeters or smaller (Davies & Welch, 2014).
This discussion may lend some support to the no-
tion that the seemingly ever-increasing incidence
rate of thyroid cancer is a result of evolving diag-
nostic processes.
Our findings demonstrate gender disparities
in thyroid cancer incidence and stage at diagnosis
(Figures 2 and 3). Previous literature suggest that
thyroid cancer detection is strongly related to an
individual’s exposure to medical care (Davies &
Welch, 2014). Gender differences in the utilization
of medical care (e.g., females use health care ser-
vices more frequently than males (Bertakis et al.,
2000)) could suggest a mechanism by which the
disparity in incidence among females occurs. Ad-
ditionally, males being more likely to be diagnosed
in the late or unstaged phases of disease than their
female counterparts lends further support for this
mechanism.
Cohort Effect
From the 1930s until the 1960s, children were
routinely treated with external radiation therapy for
benign conditions of the head and neck such as cys-
tic acne or enlarged tonsils or adenoids (ACS, 2017,
Haugen et al., 2015, Iglesias et al., 2017). After
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