Daily Briefing

18 common cancer myths, debunked

Editor's note: This popular story from the Daily Briefing's archives was republished on May 18, 2023.

After receiving a cancer diagnosis, many patients must navigate "outdated myths" about the disease and related treatments. Writing for the Washington Post, Marlene Cimons debunks some of the most common myths about cancer.

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1. Cancer is a death sentence

"Many decades ago that's how people felt because the death rates were higher and the research and treatments were not as advanced as they are today," said Mayo Clinic oncologist Karthik Giridhar. "Now we have prevention, early detection and cutting therapies and the vast majority of people are surviving longer, with increases each decade, and living better and more productive lives."

2. You can 'catch' cancer

While cancer is not contagious, certain viruses and bacteria can increase a person's risk of cancer, Cimons writes. However, "there is no need to avoid contact with someone who has cancer," she adds.

"You can hug and kiss someone with cancer, or even be intimate and there is no risk to you or the person with cancer," said Julie Nangia, associate professor of medicine at the Baylor College of Medicine and medical director of breast oncology at its Dan L. Duncan Comprehensive Cancer Center.

3. Everything around you can cause cancer—so why protect yourself?

"Everything doesn't cause cancer," said Rachel Buchsbaum, director of the cancer center and chief of hematology and oncology at Tufts Medical Center. "There are a few clear lifestyle things people can do to lessen the chance of getting it. Exercising every day. That's a big one. It's the best thing you can do for yourself, that and not smoking, keeping your weight in the normal range and limiting alcohol to less than one drink a day, which should be the target you shoot for if you are going to drink regularly."

4. Chemotherapy has terrible side effects

"This is definitely not true," Nangia said. "The supportive care medications are amazing now and most patients do very well. It is not common for patients to have nausea that is not controlled with medications or severe side effects that cannot be managed."

5. Your hair will not regrow after chemotherapy

While experts say it may take a long time for hair to regrow, it does return in most cases—but it sometimes grows back in different texture or even color.

"Chemotherapy works by attacking fast-growing cells," said Diane Reidy-Lagunes, associate deputy physician-in-chief at Memorial Sloan Kettering Cancer Center's Regional Care Network. "Cancer cells are fast growing, but so are other cells, such as hair cells. Chemotherapy can cause hair loss on your scalp, eyebrows, eye lashes, arms, legs and pubic area. Depending on your chemotherapy, you can lose hair in none, some or all these areas. Once your treatment ends, hair should begin to grow back."

6. Antiperspirants and deodorants can cause breast cancer

"This is a definite myth likely coming from the fact that when women get mammograms, they are asked not to use deodorants or antiperspirants," Nangia said. "The reason women are told this is that deodorants and antiperspirants contain aluminum which on an X-ray or mammogram can mimic calcium and interfere with the mammogram results."

7. Microwaving food in plastic releases cancer-causing chemicals

"This is only true of older plastic material and if the plastic contained chemicals like BPA or phthalates," Nangia noted. "New plastics do not contain these chemicals, and if plastic is labeled as 'microwave safe,' it does not contain these chemicals and will not cause cancer."

8. Cancer is always inherited

"Some cancers can run in families and put families at much higher risk, but the reality is that cancer can occur anytime in one's lifetime, and the prevalence increases as we age so it is a disease of aging," Nangia said. "Most people who develop cancer do not have a family history. It is sporadic."

9. Cancer is always caused by environmental factors

"Environmental factors — like smoking and diet and exposure to many chemicals, such as benzene and asbestos — do raise the risk, but not everything in the environment causes cancer," Giridhar said. "Sometimes there is no clear single reason why cancers develop. It's probably multifactorial, including exposure to certain environmental toxins, genetics or nothing obvious at all."

10. It is better if you don't know you have cancer

"Absolutely not," said Andrew Evens, associate director for clinical services at the Rutgers Cancer Institute. "Most cancers are treatable, and many are curable."

Because cancer treatments and outcomes often depend on early detection, experts emphasize the importance of routine cancer screenings, including mammograms, colonoscopies, and prostate exams.

11. Green tea will help protect you from cancer

According to according to Ting Bao, director of integrative breast oncology, integrative medicine and breast medicine services at Memorial Sloan Kettering Cancer Center, green tea contains polyphenols like epigallocathechin-3-gallate, which is a strong antioxidant.

"In vitro [lab] studies show that these ingredients may help prevent cancer by inhibiting cancer cell proliferation," Bao said. "Therefore, in theory, drinking green tea could prevent cancer. But probably one would have to drink huge amounts a day for it to have an effect."

12. Pregnant people can't receive—and should steer clear of—cancer treatment

"We usually try to avoid therapy in the first trimester to protect the baby, but it is safe to do surgery and certain chemotherapies during the second and third trimester," Nangia said.

13. Only smokers can get lung cancer

According to CDC, "the vast majority" of lung cancers—roughly 80% to 90%—occurs among cigarette smokers. But using other tobacco products and exposure to secondhand smoke and radon can also increase a person's risk of getting lung cancer.

"The odds of getting lung cancer are much lower in nonsmokers, but 10 [to] 20 percent of lung cancers are in people that have never smoked or smoked fewer than 100 cigarettes in their lifetime," Nangia noted.

14. Surgeries and biopsies cause cancer to spread

"There is a myth that exposing the cancer to air via biopsy or surgery will make cancer spread which is not true," Nangia said. "The reality is that when people have cancer requiring a biopsy or surgery, some of these cancers will be aggressive and recur. This is because of the biology of cancer, not because of the biopsy or surgery."

To prevent the spread of cancer cells, the National Cancer Institute (NCI) urges surgeons to take special precautions during surgeries and biopsies, including the use of separate surgical tools for different areas of the body.

15. Sugar makes cancer grow

"There are no data that consumption of sugar leads to cancer growth," Reidy-Lagunes said. 

While the NCI notes that cancer cells do consume more sugar than normal cells, no studies have suggested that consuming sugar worsens cancer, or that cutting out sugar mitigates or prevents the disease.

However, a high-sugar diet can cause weight gain, and obesity does increase a person's risk of certain cancers.

16. Artificial sweeteners and cell phones cause cancer

According to the NCI and several studies, there is no evidence that suggests phones or sugar substitutes contribute to cancer.

17. If there is a lump in your breast tissue, you have cancer

While CDC notes that some breast lumps are cancerous, most are not. Still, experts encourage anyone who finds a breast lump to have it evaluated. "An ultrasound can help characterize masses felt in the breast and often if it is clear, the mass is benign and a biopsy is not necessary," Nangia said.

18. Cancer always returns

"Most cancers do not come back, thankfully, and advances in medicine continue to decrease the risk of recurrence," Reidy-Lagunes said. "The number of cancer survivors living in the U.S. continues to increase." (Cimons, Washington Post, 6/10)






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