Is colon cancer preventable?
Colorectal cancer is the third most common cancer in the world
and its prevalence is increasing rapidly in certain regions. Middle
East Health speaks to Professor Heinz-Josef Lenz, an eminent
cancer research specialist based at the University of Southern
California Keck School of Medicine, about the disease, its
epidemiology, and options for prevention and treatment.
Middle East Health:
is colorectal cancer? Are there known
causes of its development? Can it be inherited?
What is the risk of it spreading
in the body?
Professor Heinz-Josef Lenz: Colon cancer
is one of the most common cancers in
the world and one of fasted growing cancers
in Asia. Most colon cancers develop from a
polyp which is a benign growth of the inner
lining of the gut. The most interesting fact
of the development of colon cancer is that
we can very effectively prevent it since it
is present in precancerous form, which we
can, in most cases, easily spot as a polyp.
Most of the colon cancer develops within
5-10 years, giving us a unique opportunity
to prevent this cancer with colonoscopies
which can identify the polyp and then it
can be easily removed. Since colon cancer
usually develops in patients older than 50
years we recommend a baseline colonoscopy
at 50 years and then every 5-10 years
depending on the findings.
We also know very well the risk factors
for colon cancer. The main factors are red
meat, alcohol, obesity and many other lifestyle factors. It is also very
recognize the symptoms of colon cancer. If
the cancer is in the left side of the colon
the symptoms are usually easy to recognize
and include constipation and diarrhoea,
blood in the stool, pain with bowel movements
and others. However, if the cancer
grows on the right side, the symptoms are
less characteristic and can be like abdominal
discomfort and are often mistreated as
stomach upset. Any on-going abdominal
discomfort should be evaluated and a colonoscopy
In addition to the lifestyle factors leading
to colon cancer, there is also a familial
form called Lynch Syndrome. If there
is any family history of colon cancer and
possible ovarian endometrium or gastric
cancer, the person should to be evaluated
for a possible genetic predisposition. Patients
with a genetic predisposition develop
colon cancer much earlier (under age
of 50) and often on the right side without
developing polyps. These patients need to
be seen by a genetic counsellor and undergo
specific surveillance. We know from
studies, if we identify this genetic predis-position, we can successfully
prevent any patient in this family dying from colon cancer while
MEH: What is the epidemiology of
colorectal cancer – in the World, the US,
Europe, Asia and the Middle East (for
HJL: The highest incidence of colon cancer is in the Western
world, South America, and now also in Asia following the spread of
Western diet in the world. In the US, the incidence has been decreasing
mainly due to more screening with colonoscopies. Asia now has a higher
incidence than the US – Japan has double the incidence of the US –
because of the change of lifestyle, increasing consumption of a Western
diet and less exercise, increasing obesity and more alcohol.
MEH: Is there a gender bias? If so, why?
HJL: Yes there is a link to gender. We know that premenopausal
women have significant decrease in the risk of colon cancer. We
also know that women who take hormonal replacement have lower
risk of colon cancer. This might be only effective on the right side
of the colon. However, postmenopausal women have the same risk
or maybe higher risk than men. We know that oestrogen plays a
role in the right-sided colon cancer and the premenopausal level of
oestrogen can prevent the development of disease.
MEH: What are the mortality figures for colorectal cancer? How
does it rank (for mortality) compared to other diseases?
HJL: Overall, colon cancer is the third most common disease and
one of the most lethal (2nd) depending what statistics you look at.
It is a major health problem around the world.
MEH: What do you recommend doctors tell their patients with
HJL: My recommendation is to avoid red meat, decrease alcohol
consumption, have regular exercise and eat the Mediterranean diet.
Get colonoscopy at 50 and if there is any family history of the disease
you may need to check for the disease earlier. If there are any
on-going symptoms in the abdomen, make sure that a colonoscopy
Colon cancer can be easily prevented with regular exercise 20 minutes
twice a week, which reduces the risk of colon cancer by 50%.
MEH: Once diagnosed – how do you classify the different
stages of progression / advancement of the cancer?
HJL: Depending on the stage of the colon cancer, we do surgery,
chemotherapy and radiation. For colon cancer located in the rectum,
we usually – depending on the tumour size – give chemo and radiation
prior to the surgery. For most colon cancers we perform surgery,
but this depends on the tumour growth in the bowel wall and if the
cancer travelled to the lymph nodes or spread to other organs. We
stage the cancer as I, 2, 3 or 4. Stage I and II disease usually don’t
require any further therapy and over 80-90% are cured.
Oncology Conference in Abu Dhabi in
November last year). Can you tell us
about these options?
JHL: The introduction of the novel
drug regorafenib is important because it
gives the oncologist a new tool in their
fight against colon cancer. It is a ‘smart
drug’ targeting a very important genetic
alteration in colon cancer enabling the
disease to grow and metastasize. This oral
medication has shown that it prolongs life
in patients who have exhausted the standard
therapies. This drug has a very unique
mechanism of action which explains its efficacy
in patients with colon cancer. It is
also easy to give and well tolerated.
MEH: Is colorectal cancer curable?
JHL: Colon cancer is a unique disease.
Even when the disease has metastasized to
the liver, we still have a chance for cure.
This is completely different to other cancers,
such as lung or breast cancer. It has
to do with the special metastatic pattern of
the disease and the ability to remove successful
liver metastases, since liver is the
only organ which can rejuvenate. With
increasing efficacy of our therapies we will
cure more and more patients. The challenge
in the future will be using molecular
testing to identify patients who benefit the
most from our therapies and the increased understanding of the molecular make up
colon cancer will not only help to select
patients, but identify new treatment options.
We are in the middle of a molecular
revolution and I have no doubt that we
will find better therapies using our increasing
knowledge of the molecular pathways
in this disease.
MEH: Do you have any specific
recommendations for doctors and / or
health authorities in the Middle East?
JHL: I have always been impressed by
the knowledge and training of oncologists
in the Middle East. I have no doubt that
the new treatments and the new molecular
testing will be quickly integrated in the
treatment of patients with colon cancer in
the Middle East. We can only understand
this disease with global collaborations. We
unfortunately know very little about colon
cancer in the Middle East since aetiology
and different ethnic backgrounds may
play a role in the development, progression
and outcome of patients with colon
cancer. It would be incredibly exciting to
better understand the genetic background
and molecular make up of colon cancer in
OncLive - Colorectal cancer
of upload: 17th Jan 2014