Diabetes Not Only Increases Risk of Breast and Colon
Cancer but Death from Them, Too
Cancer has long been linked to diabetes but this one
of first studies to look at risk of dying from these diabetes linked
Sept. 27, 2013 - Diabetes, a disease common
among senior citizens, has been linked to an increased risk of developing
cancer, but now researchers have performed a unique meta-analysis that
excludes all other causes of death and found that diabetic patients not
only have an increased risk of developing breast and colon cancer but an
even higher risk of dying from them.
More than 40% of all cases of diabetes in the U.S.
occur in people aged 65 and older. Type 2 diabetes is one of the most
common chronic diseases of aging. It develops in up to one in five older
Dr. Kirstin De Bruijn will tell the 2013 European
Cancer Congress (ECC2013) on Sunday that previous studies have examined
the association between diabetes and dying from cancer but death from
specific types of cancer has not been well-studied.
"Our meta-analysis is the first to combine
incidence and death from breast and colon cancer, while excluding all
other causes of death. We have investigated the link between diabetes
and the risk of developing as well as the risk of dying from these
cancers," she says.
Dr. De Bruijn, a PhD student in the Surgery
Department at the Erasmus University Medical Center in Rotterdam (The
Netherlands), and colleagues analyzed results from 20 trials that had
taken place between 2007 and 2012, involving more than 1.9 million
patients with breast or colon cancer, with or without diabetes.
They found that patients with diabetes had a 23%
increased risk of developing breast cancer and a 38% increased risk of
dying from the disease compared to non-diabetic patients. Diabetic
patients had a 26% increased risk of developing colon cancer and a 30%
increased risk of dying from it compared to non-diabetic patients.
Dr. De Bruijn says "The results for breast and
colon cancer incidence in patients with diabetes are consistent with
other meta-analyses. Furthermore, this meta-analysis shows a higher risk
and a stronger association between diabetes and death from breast and
colon cancer than previously reported.
"Cancer patients who are obese and diabetic are an
already more vulnerable group of individuals when it comes to surgery,
as they have an increased risk of developing complications both during
and after surgery. If more obese and diabetic patients have to have an
operation because of cancer, healthcare costs will increase.
"Worldwide, the numbers of obese and subsequent
diabetic patients are still increasing and it is a cause for concern
that these individuals are at a higher risk of developing cancer and
dying from it. Studies have already highlighted the increased risk of
developing cancer for diabetics.
“Our meta-analysis, which is unique since it looks
at the risks for breast and colon cancer while excluding all other
causes of death, provides stronger evidence for the association between
diabetes and the risk of developing and dying from these cancers. We
want to make people more aware of this problem and we hope that
prevention campaigns regarding obese and diabetic patients will focus on
highlighting this increased risk."
Dr. De Bruijn and her colleagues intend to follow
up their work by investigating what effect other factors associated with
diabetes have on cancer risk and death, such as the anti-diabetic
medication, metformin, as well as insulin and the duration of diabetes.
"It is extremely important that prevention
campaigns on obesity and diabetes are intensified and that they also
focus on children, to prevent them from becoming obese and developing
cancer later in life," she will conclude.
Professor Cornelis van de Velde, President of ECCO,
said: "With the increase in incidence of both diabetes and breast
cancer, this is an important update of the meta-analyses on this subject
and an interesting addition to the literature as this study excluded
other causes of death. As the results are consistent with earlier
meta-analyses, the substantial increased risk of breast cancer should be
part of prevention campaigns.
“For further research, it would be important to
study how other, competing risk factors might affect survival, as
elderly cancer patients with diabetes are usually diagnosed with other
conditions as well. Additionally, the potential role of metformin in
relation to improved survival and cancer recurrence needs to be
Professor Hans-Joerg Senn, scientific director at
the Tumor and Breast Centre ZeTuP, St Gallen, Switzerland, said: "The
message from the Erasmus Medical Center is disturbing and highly
important, for the medical community, as well as for the public and
politicians. It highlights once more the importance of the negative
interactions between lifestyle, metabolism, overweight and certain
frequent types of cancers, such as here between diabetes, obesity and
breast cancer as well as colon cancer. It is time for increased and more
effective information and prevention campaigns, especially in the
economically developed world, where caloric abundance is prevalent."
The 2013 European Cancer Congress is the 17th
congress of the European CanCer Organisation (ECCO), the 38th congress
of the European Society for Medical Oncology (ESMO) and the 32nd
congress of European Society for Therapeutic Radiology and Oncology (ESTRO).