As a cancer researcher and cancer survivor, I can see it from both the biomedical research side and the patient side.
Here’s my top 10 list of myths & legends about cancer.
1 ) Cancer can be 100% removed from the body. I wish it were true, but there is growing evidence that most of the time doctors cannot get all cancer out of a patient. Of course the more localized or contained that a cancer is upon diagnosis, the more likely the patient is to do well. However, there are a number of characteristics of cancer cells that we are now realizing make them unlikely to only be found in one place at diagnosis and cancer cells are so diverse that any one treatment or even several treatments may not get them all. So for most cancers, it is a myth that the doctors can get rid of 100% of the cancer cells. Thus, most often what we call “cures” are effectively cures, but do not cure the patient by removing absolutely 100% of cancer cells as most people imagine.
What makes cancer cells so hard to complete remove?
Cancer cells inherently are itching to travel. They quite literally crawl around more than normal cells and some subpopulations of cancer cells within any given tumor are likely to be especially antsy to move around. What this means is that even in a cancer that appears in the pathology report to be contained, some cancer cells may very well have crawled elsewhere and we currently just cannot detect them, but they can cause recurrence.
In addition, cancer cells are very good at making the body produce new blood vessels, a process called angiogenesis. This makes sense because cancer cells need blood close by for nutrients, oxygen, etc. However, the blood vessels stimulated to be formed by cancer cells are almost always crappy. They are weak and leaky. The usual barrier between them and tissues is full of holes. What this means is that these blood vessels provide cancer cells with an opportunity to jump ship into the blood stream. Almost all cancer cells taking such a road trip will die. They may get killed by the immune system or by the harsh conditions of being somewhere in the body they are not used to. But there will be some survivors and they are extremely dangerous. Researchers now think that perhaps in most cancers, cancer cells are in the bloodstream.
Cancer cells are diverse and hence some population will always survive any given therapy. unstable, which makes them adaptable and heterogeneous. This diversity amongst cancer cells makes it rare for any given therapy to kill them all.
2 ) Cancer is a death sentence. When I got the news that I had aggressive prostate cancer, it was literally painful and a shock. For a time I thought maybe this would be the end of me. It still could catch up with me, but so far I’m still (knock on wood) in long-term remission. The reality is that many cancers are quite treatable and the prognosis can be much better than people think. Certain cancers are almost uniformly fatal such as glioblastoma and we in the research community are working hard to find new ways to treat them that are more effective, but for most cancers these days, they are not necessarily a death sentence. It is important to keep hope and try to stay positive.
3 ) Cancer is one disease. There are literally 100s of types of cancers and in fact, I believe that every patient’s cancer is unique. What this means is that every cancer patient will respond differently to treatments and to the disease itself. Therefore, one has to be extremely careful about generalizing.
Cancer cells have unexpected diversity. The more we learn about cancer, the more we realize that even in a single patient, it might be more accurate to say this one person has “cancers”. Cancer cells are very unstable and as they grow they undergo all kinds of changes. What this means is that any one drug or one treatment like radiation is unlikely to kill them all. The more stem-like cancer cells, sometimes called “cancer stem cells” or “tumor initiating cells” are particularly unique from the rest of the tumor in patients and harder to target with therapies.
4 ) Cancers most often run in families. Hereditary cancers do form some fraction of all the cancers that are diagnosed, and some can be tracked so specific heritable mutations that one might get via the family tree. However, most cancers are not heritable, but rather are spontaneous and caused by things that we still do not understand.
5 ) Sunscreen prevents cancer. As someone with fair skin who is literally allergic to the sun (I get a rash) I have used sunscreen for most of my life. The sunscreen prevents me from getting the sun rash and also from getting sunburn. Hundreds of millions of people around the world use sunscreen. However, surprisingly, there is no evidence that sunscreen consistently lowers the rate of skin cancer. This remains a very controversial area with competing publications that often seem contradictory.
Why might sunscreen not prevent skin cancer?
What may be happening is that for many people like myself sunscreen does two opposing things. First, it blocks out a lot of UV light which is a good thing. Second, it enables people to spend long periods of time out in the sun without getting a burn or rash, and in that way increases sun exposure. Since no sunscreen is perfect at blocking UV light, the end result of using sunscreens for many or even most people may be a net increase in UV exposure since it allows them to spend so much more time in the sun.
6 ) Pesticides cause cancer. When I was a kid a wasp nest (hated yellow jackets) appeared in a bush near our house. I pulled out a can of Raid (this was in the 70s so who knows what chemical was in Raid at that time) and sprayed it. In the process the wind blew some of the Raid into my face just for a moment and I started feeling dizzy. A few seconds later I felt fine. When I was 42 years old I was diagnosed with cancer. Did that pesticide exposure cause my prostate cancer 30 years later? Or did tiny amounts of pesticides in the food I’ve eaten throughout my life cause my prostate cancer? Could that happen to you?
It is very unlikely. In fact, there is no evidence that pesticides cause cancers more generally. I don’t think pesticides are good for people, but carcinogenic? Maybe, but I’m not convinced and if there is an effect it may be small.
7 ) Cancer is contagious. While in rare cases cancer may be indirectly contagious in the sense that certain viruses (HPV-cervical cancer; HIV-Kaposi’s Sarcoma and a few other limited relationships) that can be transmitted from person to person can in some cases lead to cancer, cancer itself cannot (to our knowledge) be directly communicated form person to person. There is, however, a rare cancer in Tasmanian Devils that is literally contagious. This very freaky cancer is literally its own immortal being and its cells are transmitted from animal to animal. Whether anything like that can happen in people is unknown, but there is no evidence. So next time someone you know or love gets cancer, don’t act like they are Typhoid Mary.
8 ) Cancer can be treated or cured with herbs and supplements. The supplement industry is a multi-billion dollar business that claims to be able to cure or prevent any number of ailments including cancer. Sadly due to a legal technicality, the FDA has been mostly hamstrung in preventing supplement makers from making bogus claims or regulating them in the same rigorous way they do for drug makers. There is, unfortunately, no evidence that any supplement has any ability to do anything for cancer.
9 ) Bras, antiperspirants, breasts implants, and abortions increase your risk of breast cancer. There is no evidence that any of these things or actions increase a woman’s chance of getting breast cancer. Nonetheless these urban legends persist.
10 ) Cell phones cause a lot of brain tumors and we just don’t know it yet. While there has been some conflicting evidence as to whether the radiation that cell phones give off can increase the risk of brain tumors, to date I have not seen anything that makes me think there is a major connection. However, cells phone do give off radiation and when held up to your ear, they are certainly irradiating your brain to some extent, which cannot be a good thing. So I would say even though this remains somewhat of a myth, I think it likely that cell phones might cause a few brain tumors in the whole U.S. for example so it is probably wise especially for kids to limit the amount of time a cell phone is near the brain.