Sian is a Registrar in Surgery specialising in breast cancer at the Western Infirmary Glasgow. As she is tapering for her 4th Ironman in Western Australia she is taking some time out to talk to us about her experience with exercise and cancer.
Sian, tell us a little about yourself and what motivates you to do ironman?
Well I am in my final year of training to be a breast surgeon in Glasgow. I qualified as a doctor 11 years ago so it has taken a long time! I am also a clinical lecturer so as well as my clinical duties I also work in breast cancer research.
I have been doing ironman races for the last few years, and love the satisfaction of a long term goal and completing something that most people would think impossible. I also like the challenge of seeing if I can go a little faster each time…
You have been involved in the pioneering Active-ABC [after breast cancer] scheme can you tell us about that?
In recent years there has been increasing evidence that exercise after a diagnosis of breast cancer can improve quality of life, reduce fatigue and reduce admissions and side effects during chemotherapy. In addition, there is also less robust but still intriguing results from large epidemiological studies suggesting women who exercise post cancer have improved survival rates with figures approaching that of the benefit from chemotherapy. These benefits appear to be independent of body weight. We have therefore set up in Glasgow the first UK program offering newly diagnosed breast cancer patients a place on a formal aerobic exercise.
Do you know the underlying reasons why exercise helps cancer patients?
We still don’t know why exercise may affect survival outcome but there are several theories. Certainly weight management has a role as we know that obesity increases circulating levels of oestrogens, a bad thing if you have a hormone dependent cancer [many breast cancers are driven by hormones such as oestrogen]. Obesity also goes hand in hand with insulin resistance and we know insulin related signalling pathways are involved in breast cancer development. However there are also weight independent mechanisms as well, though modulation of immune function, the ‘anti-inflammatory’ effects of exercise and also upregulation of antioxidant regulatory systems.
We have recently blogged on excess body fat and cancer here.
Do you think the same principles can be applied to rehabilitation from other types of cancer?
The majority of the evidence has come from breast cancer but there is epidemiological evidence in colorectal and prostate cancers too. A randomised clinical trial of a 3 year exercise program in colon cancer (CHALLENGE) has started in Canada specifically to look at the effects of activity on disease free survival.
Moving on to cancer risk as apposed to rehabilitation, exercise plays an important role here too doesn’t it?
I have seen very good epidemiological evidence that exercise plays a significant role in prevention of breast, ovarian, colorectal cancers, some of the big killers in the UK. Again the science explaining the biology behind this is not conclusive but is probably by similar mechanisms as I described for survival post diagnosis. The results appear to be very significant with up to 30% reduction in risk of cancer in some reports.
Not only that, if you are physically fit and are unlucky enough to develop other cancers such as oesophageal or pancreatic which may require major surgery you are more likely to come through the operation with out major complications. Amazingly, some places are now doing what we athletes would see as modified lactate testing on a treadmill to assess fitness for surgery!
The EPIC report famously concluded that women that do more house work are less likely to develop cancer. Do you think the type or intensity of exercise is important? do you think extreme forms eg ironman loose the benefit or are detrimental. What is ‘ideal’ amount of exercise for average dude?
Well I think the housework thing looked good for the headlines but give me a run over doing the ironing anyday! The latest recommendations for adults call for at least 30 minutes of intentional moderate to vigorous activity a day, this is getting the heart rate up and feeling sweaty, on 5 or more days per week. For children, the recommendation is 60 minutes or more a day!
Before we introduced Active ABC we audited the amount of exercise women attending Glasgow breast clinics were actually doing. Only 20% were meeting these guidelines and I am not convinced that half of these weren’t exaggerating!
Instinctively you would question if extreme ironman training is altogether the most healthy thing you can do?! But when they stratified patients in the studies mentioned earlier it did seem to be that the more activity you did the better, so 6 hours vigorous exercise a week is better than 3.
And ultra marathon runners have been shown to have extremely low levels of a protein called CRP which is a marker of chronic inflammation and of poor outcome in cancers so who knows?
Some people are worried that the oxidative stress associated with exercise could increase cancer risk. Is this really something we should worry about?
The oxidative stress pathways are actually very topical in cancer at the moment, Cancer patients have higher blood makers of oxidative stress than the average population, and free radicals can damage proteins, lipids and DNA which has been linked to cancer development. However one of the theories of the benefit of exercise is that your body upregulates its own ‘anti-oxidant’ pathways which will mean more effective control in the long term over the potential cancer related oxidative stress damage.
A small study looked at acute oxidative stress damage at athletes competing in Ironman Austria , with no obvious evidence of persistent oxidative stress or DNA.
What about taking anti oxidant supplements like vitamin C or E either an athlete or as anticancer prevention?
This is a highly contentious issue. Several studies in colorectal cancer have shown that taking these supplements gave no benefit and actually may even appear to be detrimental to risk!
A possibility is that this is because the bodies own systems are no longer upregulated. Interestingly antioxidant supplements may actually cancel out the effect exercise has on upregulating the body’s own antioxidant systems.
What other factors should people be aware of when thinking about their cancer risk?
Some people will be more aware of their risk of cancer because of a family history of the disease. However this only accounts for a small proportion of cancers and most are lifestyle related. What I tell patients: Don’t smoke, exercise and eat foods of as many different but natural colours as possible! Also unfortunately, especially if you are female, don’t drink too much alcohol either!
What should people do if they are worried or want more information? If they are interested in you Active-ABC program who should they contact.
All newly diagnosed patients in Glasgow will be getting information about Active ABC. For more general information about exercise and rehabilitation after cancer this website is run by Dr Anna Campbell who has helped us set up the program.
http://www.canrehab.co.uk/
Finally, good luck in WA, what is your goal for the race and what is on the cards for next season?
Thanks, after a DNF in IM Germany this year my aim is to get to the race virus free and to finish!
