Disparities in Cancer
Nearly 1.7 million new cancer cases
and roughly 600,000 cancer deaths are
expected in the U.S. in 2017. The good
news is that this reflects an ongoing
1. 5 percent annual decline in cancer
death rates, likely having resulted in over
2 million fewer cancer deaths from 1991
to 2014. The more troubling news is
that cancer does not affect all equally.
African-Americans have cancer
death rates 15 percent higher than
Caucasians. Asian/Pacific Islanders,
American Indian/Alaska Natives and
Hispanics have higher risks of cancers
attributable to chronic infections.
Finally, low-income people disproportionately die from cancer.
Every person is unique. Analyses
of the more than 3. 1 billion base pairs
constituting the human genome illustrate this point. Although any two
individuals have DNA sequences that
are 99.9 percent identical, there are at
least 3 million differences ( 1 in 1,000
base pairs). Even identical twins, though
beginning life with identical genomes,
grow to differ in DNA sequences. And of
course, no two people, including identical twins, have the same life experiences.
Differences among individuals can
provide clues to why cancer arises
and how it might be better prevented
or treated. Inherited genes and environmental exposures both contribute.
Environmental exposures known to
affect cancer development include
diet, lifestyle, place of residence, and
occupation. Genetic and environmental
factors interact to generate individual
differences in cancer risk. As an example,
exposed to large amounts of ultraviolet
radiation from sunlight are prone to
develop melanomas and nonmelanoma
skin cancers, while darker-skinned
African-Americans develop fewer skin
cancers, whether sun-exposed or not.
These differences in skin cancer risk can
be attributed both to genes controlling
skin pigmentation and to environmental
exposures to ultraviolet light.
For prostate cancer, differences in
incidence and mortality rates among
races and ethnic groups are not as
easily explained. Prostate cancer death
rates for African-American men are
almost 2. 3 times greater than those for
Caucasian-American men. Studies of
prostate cancer biology hint that genetic
and environment differences may
account for some of the discrepancy.
But inequities in health care access also
are almost certainly at fault.
Disparities in access to and use
of high-quality health care reflect
injustices that should not be tolerated. Cancer disparities can be rooted
in inadequate insurance coverage
or inability to pay for care, lack of
proximity to health care services,
low health literacy, reduced trust in
providers and the health care system,
provider biases and prejudices, overt
discrimination, and poor-quality care.
Resolutely targeting cancer dis-
parities can yield spectacular results.
Colorectal cancer death rates historically tend to be higher for African-Americans than Caucasians in the U.S.,
and disparities are the likely culprit.
Confronting the challenge, former
Delaware Governor Ruth Ann Minner
and the state legislature launched a
colorectal cancer screening program
in 2002, ultimately allocating funds
so that all state residents, including the uninsured, would have access
to both screening and treatment.
By 2009, colorectal cancer screening rates in Delaware had increased
from 57 to 74 percent in people 50 and
older. Screening rates were similar in
African-Americans and Caucasians,
fewer colorectal cancers were diagnosed
at advanced stages, and the disparity
in colorectal cancer mortality between
African-Americans and Caucasians had
been nearly eliminated.
The current president of the American
Association for Cancer Research (AACR),
Michael A. Caligiuri, MD, has made
cancer health equity a major priority for
his yearlong tenure. The AACR, which
publishes Cancer Today, now boasts more
than 37,000 members, with expertise
spanning all aspects of cancer research
and care. It’s the perfect organization
to explore the reasons for differences in
cancer incidence and mortality rates and
to illuminate the disparities in health
care that must be overcome.
William G. Nelson, MD, PhD
Director, Johns Hopkins Kimmel
Cancer Center in Baltimore
PHOTO BY JOE RUBINO
Of all the forms of inequality, injustice in health is the most shocking and inhuman.” –Dr. Martin Luther King Jr.
FROM THE EDITOR-IN-CHIEF