Cancer myths and misconceptions

We look at the sources of some of the most common myths about cancer and provide the latest evidence to debunk them.

Bras and breast cancer

Myth: Wearing a bra to bed causes breast cancer.

Cut to the evidence: There are no well-designed research studies that show a link between wearing, or not wearing, a bra and developing breast cancer.

Tanning and cancer

Myth: If you tan but don’t burn, you don’t need sun protection.

Cut to the evidence: If your skin turns brown, it is a sign of sun damage, even if there is no redness or peeling. It's your skin's way of trying to protect itself because UV rays are damaging living cells. Tanning without burning can also cause premature skin ageing and skin cancer. All Australians need to slip, slop, slap, seek and slide during the daily sun protection times. Download the SunSmart app to find out when you do and don't need sun protection.

Family history and cancer

Myth: People are not at risk of cancer if they have no family history. 

Cut to the evidence:  Most cases of cancer are not due to genetics. One in three Australians will develop cancer in their lifetime. It is therefore not uncommon for several members of the same family to develop cancer, but in most cases, the cancers will be unrelated. However, for a small number of individuals, their family history suggests they may have a faulty gene, which means their chance of developing cancer is much higher than the average population. Cancer Council recommends all Australians should maintain a healthy lifestyle and check for unusual changes and have regular screening tests to reduce their risk of cancer.

Heat and skin cancer

Myth: You don't have to worry about sun protection on cold days.  

Cut to the evidence: It's the sun's ultraviolet (UV) radiation – not temperature – that damages your skin and can ultimately cause cancer. UV rays aren't like the sun's heat, which we can feel, or the sun's light, which we can see. That's why it's easy to get caught out by sunburn on a cool or cloudy day. 

Think UV, not heat! Check the sun protection times each day to find out when UV levels will be high enough to damage your skin. The sun protection times for your local area are available via the free SunSmart app or online at sunsmart.com.au 

Women and bowel cancer

Myth: Only men get bowel cancer.  

Cut to the evidence: Bowel cancer is the second most common cancer in Australia and it affects men and women. More than 14,400 Australians are diagnosed each year. Bowel cancer is a cancerous growth that usually starts in the lining of the large bowel. It can grow there for a long time before spreading to other parts of the body. This is why the earlier a bowel cancer is found, the better the chance of curing it. There is a 90 per cent chance of cure if the cancer is found at an early stage. You can help to reduce your risk of bowel cancer by:

Symptoms and cancer

Myth: All cancers have symptoms. 

Cut to the evidence: Many cancers are asymptomatic, or do not have symptoms, and that is why screening is so important. Screening for breast, bowel and cervical cancer saves lives. If you're over 50, have a bowel cancer screening test every two years. Women aged 50 to 74 should have a mammogram every two years to screen for breast cancer, and all women aged 18 to 70 who have ever been sexually active should have a Pap test every two years.

Chlorine and cancer

Myth: Drinking and swimming in chlorinated water can cause cancer.  

Cut to the evidence: There is no evidence to support the myth that drinking chlorinated water or swimming in chlorinated pools can cause cancer. However, chlorine and chlorine gas can aggravate respiratory conditions and high concentrations of chlorine can lead to many health complications. 

Dental fillings and cancer

Myth: The mercury from metal dental fillings can escape, travel to organs and cause diseases, including cancer.  

Cut to the current evidence: To date, there is no evidence that amalgam fillings – which can be made of a mixture of mercury with silver, tin, and copper – have any other adverse health effects. The only possible risk is that amalgam dental fillings can sometimes cause local side effects or allergic reactions. These hypersensitivity reactions are rare and can be treated by removing the amalgam filling. There are alternatives to amalgam fillings which can be used if you are still concerned about the carcinogenicity of mercury. However, it is not advised that you remove your current amalgam filling to replace it with another filling.

Deodorants and breast cancer

Myth: Applying deodorant or antiperspirant after shaving causes breast cancer 

Cut to the current evidence: There is no basis for the myth that applying deodorant or antiperspirant after shaving will increase the risk of cancer. The Journal of The National Cancer Institute published a study in 2002 exploring the relationship between breast cancers and antiperspirants or deodorants in 1,606 women. The findings did not show an increased risk of cancer among deodorant or antiperspirant users, or among women who shaved before using deodorant or antiperspirant. The American Cancer Society states that the main risk related to using these products is that they can cause skin irritation if a razor nick or cut is infected. 

Sunscreen and cancer

Myth: The use of nanotechnology in sunscreen causes cancer.  

Cut to the evidence: The potential for titanium dioxide and zinc oxide nanoparticles in sunscreens to cause adverse effects depends primarily upon the ability of the nanoparticles to reach viable skin cells. The weight of evidence to date, confirmed by an updated review in 2009 by the Therapeutic Goods Administration, suggests that titanium dioxide and zinc oxide nanoparticles in sunscreen do not reach viable skin cells; rather, they remain on the surface of the skin and in the outer layer of the skin that is composed of non-viable cells.

Evidence also shows that sunscreen has been proven to reduce the risk of skin cancer – melanoma and non-melanoma skin cancer – so it could in fact be dangerous to your health to ditch the sunscreen.

Skin cancer claims more than 2,000 lives each year in Australia and it's important that sun lovers continue to protect themselves with all five sun protection measures when ultraviolet (UV) radiation is at damaging levels.

Toothpaste and cancer

Myth: The chemicals found in some toothpastes, soaps, shampoos, bath products and moisturisers – sodium lauryl sulfate and sodium laureth sulfate – cause cancer.  

Cut to the evidence: There is no evidence for the carcinogenicity of either sodium lauryl sulfate or sodium laureth sulfate. National Industrial Chemicals Notifications and Assessment Scheme concludes that irritation is the only health hazard associated with the chemicals. This irritation only occurs at the high doses used in laboratory studies, and is unlikely to occur during normal household use.

Heard other claims about cancer and want to know if they are fact or fiction? Visit iheard.com.au

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