Colorectal cancer risk factors in Nigeria
Prof Olusegun Alatise - Obafemi Awolowo University, Ife, Nigeria
The study came about because, like I said, the incidence of colorectal cancer is rising in Nigeria. As a clinician, I meet patients every day with colorectal cancer. In my clinic what they ask me, every day, ‘Doctor, what have I done wrong? What have I eaten? What habits have I taken that are actually predisposing me to this cancer?’ Unfortunately if you ask most of them do they have a family history of colorectal cancer – none. Do they smoke? None. Do they take alcohol? None. Most of the risk factors that are associated with colorectal cancer in most high-income countries are relatively absent in our population and that’s what motivated us to look at how do we identify the risk factors that are important.
Many people believe their colorectal cancer is related to diet. What has changed in our diet? Could it be environmental? That’s why we are doing a number of funded research. One of our research is looking at what are the modifiable risk factors. We are looking at the diet, we are looking at habits, be it smoking, be it alcohol intake. We are looking at ways of quantifying the amount of food because we work with a number of food scientists that help us to quantify the amount of calories that have been taken, a true picture, validation and all that. So we are running about 10-15 pages of questionnaire to assess modifiable risk factors among our colorectal cancer patients.
So we are recruiting about 600 colorectal cancer. We are about 500 currently with just about 100 to complete this study. We are comparing that with 1200 controls - we have reached a 1,000 mark, just about 200 to complete the study. So when we finish this we are going to evaluate what are the modifiable risk factors that our patients that have colorectal cancer have compared to the controls.
The way that we select the controls is that we try to match those controls based on gender, based on the environment that they are coming from and some other factors that we can balance and that we can control for. So that, at the end of the day, the control can exactly match up with the cases and we will be able to decipher what are the factors that need to be looked at to reduce the incidence of colorectal cancer.
More importantly, we are looking at the environment because some of us believe that probably much has not changed in terms of our habits but more has changed in terms of our environment. Because of industrialisation a lot of environmental fumes and the like. We are doing it funded by the NIH; we have the wristband that we have distributed to some colorectal cancers and controls in this study. So this wristband has the capacity of absorbing environmental pollutants that may be injurious to the health of the patient. So what we did was to give those wristbands to our patients to take home and they wear it for about a week and bring it back and then we send it to the lab.
Hopefully the next few months we will have the results back and from these two big studies we will be able to assess what has changed in our environment that may be injurious and fuelling the increase of colorectal cancer in our environment. Two, we will be able to identify what are the modifiable risk factors that are peculiar to our colorectal cancer patients and subsequently be able to advise our community appropriately. It’s an exciting day, those data, I’m waiting eagerly to see those data coming out so that we can advise our people. As a clinician, when my patient asks me next time, ‘What have I done wrong?’ I will be able to tell them, ‘This is what we have found.’ Not following what is in the textbooks that I know is not useful to them. I will be able to tell them confidently, ‘This is what we have found and this is the advice that I have for you.’
