World Congress on Gastrointestinal Cancer
Prevention best ‘treatment’ for colon cancer
Professor Nadir Arber – Integrated Cancer Prevention Center, Tel Aviv Medical Center, Israel
http://ecancer.org/tv/conference/149/1595
Can you introduce yourself to the ecancer.tv audience and tell us about your research?
My name is Nadir Arber, I am Professor of Medicine and Gastroenterology at Tel Aviv University and Tel Aviv Medical Centre. As a gastroenterologist I understand that the best way to treat cancer, and in particular colorectal cancer, is by early detection and preferably by prevention. Colon cancer, I guess, is the ultimate demonstration of how you can prevent cancer. You scope a patient, you find a polyp, you take it out, you prevent the final stage of the colon cancer. With more than 1.2 million new cases that are expected this year, colorectal cancer can be prevented by up to 90% of the cases. Maybe I’m exaggerating and it’s only 70 or 80%, it’s still huge numbers and it’s only by doing a simple test. So there are ample screening tests but the most important one, the gold standard nowadays, is colonoscopy and this is the way to go; everyone by the age of fifty should undergo colonoscopy. People ask me what are the symptoms for patients for early detection, what are the symptoms. So it’s very easy – it’s somebody that is 50, is feeling excellent, good appetite, those are the alarming symptoms of early detection of colon cancer. This should be kept in mind.
How has screening for CRC changed over the years?
The most established one, until recently, was faecal occult blood testing. It was done, even this had randomised trials, and it was shown that it can reduce the mortality from colorectal cancer by 15%, 18%, but only if it was done every year. These sorts of things can be acceptable and achieved in clinical trials but there in the public it’s difficult to achieve, people are reluctant to play with their stools and you cannot do it. The outcome of doing a once in a lifetime colonoscopy as compared to doing faecal occult blood tests every year for 25 years is much better with the colonoscopy. So now there is a shift and now we have much more data, clinical data, showing that doing endoscopy, most probably colonoscopy, is the best way to go. It is based on all kinds of indirect evidence like the 25 years of follow-up from the National Polyp Study that was conducted by Sid Winawer and Ann Zauber and was first published in the New England Journal of Medicine in 1993 but also now they had two months ago another report confirming that the prevention of colorectal cancer was there even if somebody did only a one time colonoscopy. There’s also indirect evidence coming from sigmoidoscopy – that was a study by Wendy Atkin showing that doing screening sigmoidoscopy can reduce the mortality from colorectal cancer by 30-40% and, obviously, if it is so for sigmoidoscopy for one rest… we can understand and extrapolate that it’s also going to work for the other rest… the rest of the right side of the colon.
Is there any value in screening people for CRC under the age of 50 years?
It is the age of 50 so there is no doubt this is the recommendation of all the societies unless there are symptoms or family history. If there is a family history of cancer in the family, colorectal cancer, then screening should start at the age of 40 or 10-15 years before the youngest case, youngest patient, in the family. But when I discuss it with my patients and then money is less of an issue, we discuss sometimes they can start to do it at the age of 40 because we know that a polyp, this is a predictive marker, develops about a decade before the cancer. So if somebody is prone to have cancer at the age of 50, and if you’d like to prevent it, he should undergo a colonoscopy somewhere in-between 40-50. So I think maybe if we’re not thinking of the money issue, maybe somebody can also start with it at an earlier age but obviously we should stick to regulations. If everyone will do a colonoscopy at the age of 50 I’m going to be very happy because we are still very far from achieving this goal.
Screening for CRC applies to both men and women?
Still the recommendations are to start for men and women at the age of 50. We know that men have slightly more tendency to develop polyps, slightly more to develop colorectal cancer, slightly at an earlier age but the differences are not that huge that we should make it into a recommendation. There are some people who say that maybe scanning should start for men at the age of 45 and for women at the age of 55 but, again, this is fine tuning. If the masses are going to accept and adhere to what we recommend, this huge problem of cancer, 1.2 million new cases every year, can be significantly reduced.
You are also talking about chemoprevention at this meeting, what are the main points you will be highlighting?
Because that’s what I used in my talk in our session, so colorectal cancer can be prevented by early detections, lifestyle modifications. It’s still simple things like exercising, quitting smoking, not drinking, losing weight, can significantly influence overall the morbidity and mortality in particular of colorectal cancer but it’s not easy to achieve so screening also. We have a major lack of compliance from the public; Maybe New York is the highest, they reach about 60% doing colonoscopy, but this is the highest number around the world; in the rest of the world it’s around 15, 20, 25%, it’s far from perfect. Also it’s difficult to do lifestyle modifications so we’re left with chemoprevention. Chemoprevention means to give a drug or a nutrient that can be given more than the usual dosage in order to prevent or redress the polyp and this is becoming more and more acceptable, especially in high risk populations. So if we are able to choose something that is harmless like cocamide is something that we developed in Israel, or we have most of the data regarding a non-steroidal anti-inflammatory drug in aspirin. Coming back to aspirin, maybe aspiring might be the magic bullet, magic drug, because we should not focus, and this is a mistake of most of the studies, they’re focussing on one organ. Colon cancer is a chemical disease, Alzheimer’s, but when a patient comes to me, he doesn’t care if I can prevent one disease but he’s going to die from another disease, he would like overall to improve his mobility and mortality. And that’s what I think we should calculate when we are coming to this new era of personalised medicine. When the patients come to me, I should calculate what is his likelihood of developing colon cancer and developing all these kinds of models but even being 50 is enough. And then what is the likelihood of developing ischemic heart disease and we also have modelled this based on the Framingham study. So aspirin has the most known effect on ischemic heart disease and colon cancer. If we can calculate the likelihood of somebody developing ischemic heart and colon cancer, we should advocate him to take aspirin whilst those at lowest risk of ischemic heart disease disease, low risk for colon cancer, maybe he should not have it. Somebody at low risk for colon cancer is somebody that has a negative colonoscopy, he’s fit, he’s exercising, he doesn’t smoke, doesn’t drink, no family history, so he’s at low risk for colon cancer. Having said that, he’s also at low risk for ischemic hear disease so maybe he should not receive but somebody with a family history, obese, history of polyps, those definitely should receive aspirin. So this is what I believe we are going to come into, this is personalised medicine. So we can build on those two major organs, colon cancer and maybe we can add some other diseases and based on this we can give patients a number – this is your likelihood of developing cancer, ischemic heart disease, and I guess each person, once we’ve given the data, should decide for himself. This is personalised medicine.
Do you have a take home message from the meeting?
I think this is an exciting meeting. It’s excellent, excellent papers presenting, but still the mortality from cancer has not dramatically reduced in the last forty years. So it is still important, even for colon cancer, for metastatic colon cancer, it used to be a few months, now it’s more than a year. But still the effect is not that strong. If we can prevent the disease at a very low cost, I’m not talking about money, because all of these diseases shouldn’t but are prescribed now, have a lot of side effects. It’s not easy so we can prevent it. So no doubt in my mind that everyone should undergo screening, any screening is better than nothing, but the gold standard is colonoscopy.
Anything else you would like to add?
I think maybe also it is important now, I think we should increase the compliance of the patients. I guess if we can combine screening colonoscopy with a chemopreventive agent like low dose aspirin, 100mg per day, which is not very toxic, then we can increase the likelihood of the patient participating in screening trials, maybe we can learn from the time between colonoscopy, once every 5-10 years, maybe it’s going to be every 10 years, every 20 years. I think these combinations of screening and a low dose of chemopreventive agent like aspirin might be very beneficial.
