Myth: People with cancer shouldn't eat sugar, since it can cause cancer to grow faster.

Fact: Sugar doesn't make cancer grow faster. All cells, including cancer cells, depend on blood sugar (glucose) for energy. But giving more sugar to cancer cells doesn't speed their growth. Likewise, depriving cancer cells of sugar doesn't slow their growth.

This misconception may be based in part on a misunderstanding of positron emission tomography (PET) scans, which use a small amount of radioactive tracer — typically a form of glucose. All tissues in your body absorb some of this tracer, but tissues that are using more energy — including cancer cells — absorb greater amounts. For this reason, some people have concluded that cancer cells grow faster on sugar. But this isn't true.

However, there is some evidence that consuming large amounts of sugar is associated with an increased risk of certain cancers, including esophageal cancer. It can also lead to weight gain and increase the risk of obesity and diabetes, which may increase the risk of cancer.

Myth: Good people don't get cancer.

Fact: In ancient times, illness was often viewed as punishment for bad actions or thoughts. In some cultures that view is still held.

If this were true, though, how would you explain the 6-month-old or the newborn who gets cancer? These little ones haven't been bad.

There's absolutely no evidence that you get cancer because you deserve it.

Myth: Cancer is contagious.

Fact: There's no need to avoid someone who has cancer. You can't catch it. It's OK to touch and spend time with someone who has cancer. In fact, your support may never be more valuable.

Though cancer itself isn't contagious, sometimes viruses, which are contagious, can lead to the development of cancer. Examples of viruses that can cause cancer include:

  • Human papillomavirus (HPV) — a sexually transmitted infection — that can cause cervical cancer and other forms of cancer
  • Hepatitis B or C — viruses transmitted through sexual intercourse or use of infected IV needles — that can cause liver cancer

Talk to your doctor about ways to protect yourself from these viruses.

May. 05, 2014 See more In-depth