Preventing cancer: dietary lifestyle or clinical intervention?
In Australia, colorectal, prostate and breast cancers are the most frequently occurring cancers in our society, a pattern that is quite different from that of underdeveloped countries. While diet is largely responsible for these differences, technological advances mean that the solutions can be viewed as systematic, financial, lifestyle or technological. They range from those that require self-discipline and care for personal well-being through to those that are seemingly a quick technological fix that will work in spite of an unhealthy lifestyle. There are three main approaches available for prevention of these cancers: dietary lifestyle, chemoprevention and screening. It has been estimated that the potential for prevention by a healthy dietary lifestyle is excellent and might reduce the burden of breast, prostate and colorectal cancer by 33-55%, 10-20% and 66-75%, respectively. This should be safe and inexpensive and have collateral benefit such as reduced cardiovascular disease and osteoporosis. But, population compliance with more plant-based, less calorie dense foods is uncertain, the most healthy are likely to be the most compliant and evidence for effectiveness when interventional programs are undertaken is disappointing. It is not clear how dependable the dietary approach would be where inherited genetic factors determine risk for one of these cancers. Chemoprevention, the administration of natural or synthetic agents that delay, slow down or inhibit the process of tumorigenesis, are still under development and study. Hormone receptor modulators for breast and derivatives of non-steroidal anti-inflammatory drugs for colorectal cancers seem to have most promise and may reduce tumour incidence or death by as much as 50%. These agents are simpler to comply with than changing dietary lifestyle and they are more potent, hence they may be of particular value in high-risk settings. But they are likely to be more costly and run the risk of adverse effects with few collateral benefits. Screening, or the testing of an individual for a disease when that individual does not have any symptoms or signs suggesting that the disease is present, aims to prevent or delay the development of the cancer. Screening impacts on mortality more so than on incidence, reducing colorectal cancer mortality in the range 15-60% and breast cancer mortality by 23-37%. Screening has the advantage of being effective in high-risk as well as average-risk groups and is an 'easy' solution for the person who elects not to follow a healthy dietary lifestyle. Nonetheless, it is expensive, demanding on resources, provides no collateral benefits and does not have the same potential to reduce incidence of disease as does the dietary approach. With these Western cancers, we are fortunate that there are options for prevention. At least choices are available and some will suite certain circumstances and personalities more than others.
Young
Graeme P
GP
Department of Medicine, Flinders Medical Centre, Flinders University of South Australia, Bedford Park, Adelaide, Australia. graeme.young@flinders.edu.au
Le Leu
Richard K
RK
D001315:Australia; D001943:Breast Neoplasms / Q000517:prevention & control; D018890:Chemoprevention / Q000379:methods; D015179:Colorectal Neoplasms / Q000517:prevention & control; D005247:Feeding Behavior; D005260:Female; D006801:Humans; D008019:Life Style; D008297:Male; D008403:Mass Screening; D009369:Neoplasms / Q000517:prevention & control*; D010349:Patient Compliance; D011471:Prostatic Neoplasms / Q000517:prevention & control