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SA JOURNAL OF DIABETES & VASCULAR DISEASE
DRUG TRENDS
VOLUME 14 NUMBER 2 • DECEMBER 2017
81
Drug Trends in Diabetes
Diabetes and cancer: is there a link?
A
n estimated up to 4.6 million people
are living with diabetes in South Africa
and an alarming 60 000 new cases of
cancer are reported annually, according to
the South African National Cancer Registry.
Dr Jay Narainsamy, specialist physician/
endocrinologist, Centre for Diabetes and
Endocrinology (CDE), says, ‘It is important
to delve into the link between these two
prevalent conditions in the hope that this
understanding may lead to better lifestyle
choices and positive changes in clinical
management.’
The link between diabetes and cancer
was considered as early as 1959. A report
in the
New England Journal of Medicine
in
March 2011 looked at causes of death in
patients with diabetes. ‘The article estimated
cancer-related deaths at seven per 1 000
person-years and four per 1 000 person-
years among men and women, respectively.
Diabetes was associated with an increase in
cancer-related deaths involving the pancreas,
ovaries, liver, colorectum, breasts, lungs and
bladder,’ explains Narainsamy.
Diabetes and cancer have a number of
common risk factors, some of which are
modifiable and some not. Non-modifiable
risk factors include age, gender and ethnicity,
with increased risk in older people, men and
in the African-American population in the
United States. Modifiable risk factors include
obesity, diet, physical activity, smoking and
alcohol abuse.
‘Obesity is linked to the development
of insulin resistance and type 2 diabetes.
It is thought that the high levels of insulin
produced by the body to compensate for
insulin resistance and obesity-associated
inflammation may precipitate cancer
development,’ says Narainsamy. ‘In
addition, diabetes itself (especially if not
controlled) may cause vascular damage and
an inflammatory state, which may create an
environment for tumour development.’
Diets low in processed meats, red meats
and with a high content of vegetables, fruit
and whole grains aid in lowering the risk of
developing certain cancers. A healthy diet
may also lead to weight loss and reduce
the risk of developing insulin resistance
and diabetes. Increased physical activity has
been shown to reduce the risk of certain
types of cancer as well as improving overall
health. Smoking and alcohol intake are both
associated with the development of cancer
as well as diabetes.
‘On a further positive note, the oral
diabetes medication, metformin, which is
our first-line drug of choice for patients with
type 2 diabetes, has been shown to inhibit
abnormal cell growth and has potential
anti-cancer properties. Further studies are
currently underway to assess the interaction
between metformin and cancer, she says.
The link between diabetes and cancer in
the other classes of oral diabetes agents are,
however, less conclusive. ‘On the opposite
spectrum, injectable insulin was thought
to be associated with an increased risk of
cancer development. However, this has not
been conclusively proven and risk is probably
better evaluated in the context of duration of
diabetes, other oral diabetes agents already
on board and poor glycaemic control.’
‘There is undoubtedly a link between
diabetes and the development of certain
types of cancer. With this in mind, it
is important that doctors ensure that
routine screenings for at-risk patients are
completed timeously. They also need to be
vigilant for “red flag” complaints and act
promptly to investigate these problems,’
says Narainsamy. ‘While further research
still needs to be done on the links between
diabetes and cancer, the positive take-
away message is that foundational lifestyle
therapies for diabetes, including healthy
eating, increased physical activity, weight
loss and not smoking, as well as our first-
line pharmacological therapy, metformin,
may have the additional benefit of reducing
your cancer risk,’ she concludes.
Placing diabetes management firmly on the table
‘T
he diabetes tsunami is here.
Unless we meet it head on
with appropriate management,
this condition is single-handedly
set to break the healthcare
system, if not the entire
economy, in the next decade.
This is the view of Dr Larry
Distiller, specialist physician/
endocrinologist and principal
physician,
and
executive
chairman of the Centre for
Diabetes and Endocrinology
(CDE).
Distiller says at this time of year, when
many schemes are announcing their benefits
packages for 2018, and people with diabetes
are mulling over their medical aid options,
it is important to review what
programmes are in place for
the management of diabetes.
He says that unfortunately,
diabetes is often treated ‘on the
cheap’ to save costs in the short
term. ‘A patient not seeing a
nurse and registered dietitian
costs less than someone who
does. While no care may look
cheaper than good care in the
short term, we know that this
is definitely not the case in the
longer term. If we look at UK data, we see
that complications of uncontrolled diabetes
account for most of the overall costs of
the condition (80%), while treatment and
management only accounts for 8%.’
Distiller says it is regrettable that diabetes
is often not ‘treatable’ due to the cost
barriers for the patient. Just because you
have medical aid does not guarantee that
you will automatically receive care.
‘When you consider diabetes remains
the most common cause of blindness in
the Western world, the leading cause of
kidney failure, dialysis and transplantation
and the most common factor in lower-limb
amputations, this lack of care becomes
significant,’ he says. It is linked closely to the
otherwell-known risk factors for heart disease
and death, namely high blood pressure, high
cholesterol levels and obesity and is also a
major cause of acute hospitalisation.
‘Good management of diabetes has the
potential to reduce acutehospitalisation rates
Dr Larry Distiller