What Are The Odds That I’ll Catch Cancer?

We mean no disrespect here, but too many of us  – in the 21st century! – have some wild ideas about the causes of serious illnesses, especially cancer.   It isn’t just fanciful Medieval philosophers and poets who attribute disease to common personality quirks or parental indiscretions.  There is all sorts of scare mongering going on out there; thanks to the Internet, one theory more wacky than the next is given elaborate attention.  Plastic water bottles, cell phones, deodorant, bad thoughts, tight clothes, children’s books – cancer’s secrets are somehow hidden in all these things, and more.   It’s all pretty overwhelming sometimes.   And stressful.

And not true.  Thank goodness.

We have enough to worry about without adding myths about cancer to the list.  Here are a few beloved – and false – proposed causes of cancer:

  • Myth: People with cancer should not eat sugar or sweets, because these things make cancer grow faster: No, sugar does not make cancer grow at a faster rate.  This notion may be based on a misunderstanding of PET scans, which use a small amount of radioactive tracer, most often a form of glucose.  All the body’s tissues absorb some of this tracer; tissues that use more energy, including the cancer cells, absorb more of the glucose tracer.  But this does not in any way support the conclusion that cancer cells grow faster on sugar.  All cells depend on blood sugar (glucose) for energy.  More sugar does not speed the growth of cancer cells; less sugar does not slow down cancer growth.
  • Deodorants and antiperspirants cause breast cancer.  There is simply no conclusive evidence to link underarm deodorants or antiperspirants to breast cancer.  Some studies report that there are substances, including aluminum compounds and paraben, in these products that can be absorbed through the skin or enter the body via shaving nicks that are irritants. If you are concerned or cautious, go without this underarm protection; better still, use deodorant products that do not contain chemicals that worry you.
  • Cancer-causing substances are released into foods microwaved in plastic containers and wraps.  If foods are heated in microwave-safe plastic containers and wraps, they are okay.  However – and this is important – plastic containers not intended for microwave use may melt when heated and leak chemicals  into the food in the process.  This is never good.  So, out with take-away containers and the odd butter or margarine tubs.  Microwave foods only in containers specifically labeled ‘microwave safe’.  
  • Cancer is contagious.  No.  You cannot ‘catch’ cancer.  Spend all the time you can with someone who has been stricken with the disease.  It’s okay to touch them.  It’s important to touch them.  However, while cancer is emphatically not contagious, sometimes viruses that are contagious can lead to a cancer’s development.  Viruses that can cause cancer include human papillomavirus (HPV), a sexually transmitted disease that can cause cervical and other forms of cancer;  Hepatitis C, a virus transmitted through the use of an infected IV needle or through sexual intercourse that can cause liver cancer.
  • Only bad people get cancer.  Nope.  There is no ‘deserved’ cancer or ‘punishment’ cancer or ‘divine intervention’ cancer.  There is absolutely no evidence that you get cancer because you should, because you somehow earned it with misbehavior.
Now that we’ve settled that, what are our real risks of developing cancer?
Scientists talk about risk in terms of probability.  This means the chance that something may occur, of course, not the certainty that it must occur.  Large groups, in fact, the larger, the better, are studied when risk estimates for cancer and other diseases are developed.  The point is to discover the probability that any given individual, or category of individuals, will develop a disease over a specified period of time.  Then the characteristic behaviors associated with that disease are studied, and increased risk factors, or decreased risk factors, are then determined.
Risk is usually divided into two categories: absolute risk and relative risk.
Absolute risk in this context refers to the actual numeric chance or probability of developing cancer or another serious disease during a certain time period – within the next five years, say, or by age 65 or over a lifetime.  Relative risk involves a ratio or a comparison instead of an absolute value.  For example, relative risk may compare and contrast the lung cancer risk for smokers over a group of people in the same demographic who do not smoke.
Tomorrow, we will go over absolute and relative risk in more detail, talk about cancer risk statistics and what they actually mean for each of us and see how risk studies are designed.  Understanding what’s out there should help us keep things in perspective.  At least until the next blazing tabloid headline scares us all over again.

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