In 2017, a CBS poll found that more than half of all US residents had a family member who had been diagnosed with some form of cancer. That means nearly all Americans have a connection to the disease, whether it's through themselves, family, or friends.
According to the US National Cancer Institute, there are more than 100 diagnosable variations of cancer. And though there have been tremendous medical advances in treatments, most cases have no definitive cure.
Although there are many events that promote education about the disease and advocate for people with it, there's still a lot the general public is unaware of when it comes to cancer.
Business Insider spoke with Dr. Pamela Crilley, the chair of the medical-oncology department at the Cancer Treatment Centers of America, and Dr. Narjust Duma, the chief hematology and oncology fellow at the Mayo Clinic, to debunk some common myths about cancer.
Part of this myth comes from misunderstanding how people develop cancer in the first place. Duma told Business Insider that "cancer starts with regular cells that went the wrong way".
While Duma fully supports people embracing a healthy lifestyle through eating well, exercising, getting enough sleep, and minimizing alcohol consumption, she said it's important to remember making these choices only reduces your risk of getting cancer.
"Kale is good, but if you eat four pounds of kale a day, it doesn't mean you won't get cancer," she said. "Vegan patients get cancer. Unfortunately, yoga instructors get cancer. There is a confluence of bad luck, genetics, and environmental factors."
"Cancer is not contagious," said Crilley. "So if you have a friend or family member who has cancer, you're not going to catch it from them."
But while cancer itself can't be transmitted between people, certain viruses that could lead to cancer can be.
"We know there are some causes that are infectious," Crilley said. She pointed to the human papillomavirus virus, or HPV, which can be transmitted sexually and is "responsible for a large number of cervical-cancer cases".
"A lot of people can have HPV infections and not get cancer, but there are some subtypes of HPV that cause someone to get cervical cancer," she said. "In addition, you can get cancer from Epstein-Barr virus in the form of nasopharyngeal cancer. You can also get liver cancer from hepatitis B."
One common assumption about cancer is that it's purely the result of genetics and passed down like curly hair or green eyes. Duma said this is not the case.
"Genetics can be a factor, but the majority of cancers are associated with secondary, environmental factors," she said. "Sometimes it is just bad luck."
However, this means the reverse is true: having no family history doesn't guarantee you won't ever develop cancer.
Duma further explained that cancers that get passed through families are caused by gene mutations that are passed through DNA.
"We all make cancer cells," she said. "But our immune systems recognize the abnormal cells and kill them with these special cells - let's call them police cells - so the abnormal ones don't grow anymore. The issue with genetic cancers is they have mutations in the genes, so these, 'police cells' go around trying to kill those abnormal cells, but it's not working, so those cancer cells grow without being told to die by these police cells. So we all make cancer cells, but people with genetic cancers are those who are deficient in those cancer-killing cells or mechanisms."
Although not smoking has many health benefits, it doesn't guarantee you won't get lung cancer. Secondhand smoke can harm someone who has never smoked a day in their life, and it's not the only passive way someone can develop cancer cells in their lungs.
Crilley said another cause could be "random or other environmental toxins." She gave an example of a case several years ago in which she said genomic testing revealed that a group of younger women who were non-smokers suddenly developed advanced lung cancer and had a higher incidence of mutated genes and abnormal proteins in their bodies.
"Unfortunately, the easiest way to say it is that some cancers are simply due to bad luck," Duma said.
While it's always a good idea to perform self-examinations, it's important to remember that not all cancers or tumors present as visible lumps.
Duma said tumors are classified as either liquid or solid. Solid tumors, which are present in breast and prostate cancers, are the ones people associate most with images of cancer. Liquid tumors are present in blood cancers, like leukemia, and are less noticeable. But people often don't feel anything when they have a tumor, as some tumors can be buried deep in an organ or too small to detect.
"Many cancers are painless," Duma said. "Unless they are very large and pressing against other organs, the [patient] won't develop any symptoms. The liquid tumors are even worse because they are a form of blood cancers that are moving through your bloodstream but don't have a lump that you can feel.
While people may use the term tumor and cancer interchangeably, the two mean different things. According to the National Cancer Institute, cancer refers to the group of diseases that cause abnormal cell growth and tumor refers to the mass of tissues that forms when the body's cells divide too much.
"A tumor means a lump or a mass, and it could be benign or malignant," Crilley said. "A malignant tumor has the capacity to metastasize, or move from its primary site to another site in the body. A benign tumor does not."
She said a benign tumor could be a cyst or a lipoma, adding, "A pathologist can look at a cut of these tumors under a microscope and decide if it is malignant or benign".
Some patients with cancer don't experience any noticeable symptoms.
Duma said: "It all depends on the type of cancer. There are so many types, and so many possible symptoms. And just because there are [symptoms] that are more common than others, doesn't mean you will present it if you have that cancer. In lung cancer, cough is the most common symptom, but I have patients who never had any cough prior to diagnosis. And in colon cancer, blood in the stool is the most common symptom, but we have patients who never experienced that once."
Crilley said that when a cancer is metastatic, it can manifest itself in ways that create unexpected symptoms. "A person could present with an enlarged liver and pain in the abdomen, and it could be that the lung cancer has metastasized to the liver," she said. "In this case, the presentation isn't even in the lung; it's in the site of where the cancer went."
Since there are no definitive symptoms, both doctors said it's important to get screened for certain types of cancer, even if you're in good health.
Crilley told Business Insider, "One thing I often get asked is whether if you eat more sugar, you're going to make your cancer grow faster, but I've never seen any data to suggest that [eating sugar] is going to fuel the cancer."
Duma said the misconception often leads people to commit to strict sugar-free diets they don't need to be following.
"Because these cells are so aggressive, they are able to feed on anything, so a sugar-free diet won't make your cancer stop growing," she said. "And it can be hard for us in oncology to see a patient losing weight not because of the cancer but because they have completely cut out sugar."
"Going through chemotherapy is hard enough, and I'm sure a bite of chocolate here and there won't hurt," she said.
"Patients [usually] only get admitted to the hospital if they have to have surgery or if they're having some side effect," Crilley said. "But with most patients with cancer, over 90% are outpatient, and they are doing much better than they used to in general." Outpatient treatment allows people to receive care on certain days but still live in their own home.
Duma said outpatients come to a hospital "a few times a week to receive chemotherapy or radiation, and then they go home." She added, "Usually the patients who are spending the most time in the hospital are those who have the liquid cancers, like leukemia."
Contrary to popular representations, not every person with cancer goes bald.
"If a patient loses their hair, that can actually be from treatment," Crilley said. "For example, if they have radiation to the brain, they may have hair loss. Chemotherapy and some hormonal agents can cause hair loss and inhibit the growth of the hair follicle."
She said that "patients who have chemotherapy may lose their hair for a few months, and then it comes back," and that many people "don't lose their hair at all" or lose it "only for a short period."
Duma said: "The decision about chemotherapy is very personal. It depends on the benefits for the patient. For example, a lot of elderly patients may decide not to pursue it because they may die of something else. If chemotherapy is only going to increase your mortality by 5% and you've had multiple heart attacks, then it doesn't make sense to go through chemotherapy."
She added that religious, cultural, or economic factors can influence a person's choice to opt out of the treatment.
"Chemotherapy is very expensive," she said. "A lot of patients may say they don't want chemotherapy just because they know if they choose therapy, they may leave their families with large debts."
Crilley said determining what treatment a patient receives for their cancer is a complex process.
"Let's say you have a solid tumor," she said. "[A doctor] would first want to make a diagnosis. A pathologist looks at a sample of the tumor under a microscope and decides what kind of cancer it is. You determine the extent of the disease, and then you look at the evidence for what is the best treatment for the patient at that stage of the disease. Some patients may only have surgery and that's all they need, other patients may have all three - surgery, radiation and chemotherapy. Some patients may only need radiation."
While chemotherapy, which came about in the 1900s, is sometimes an effective treatment, patients now have more options for treating cancer than ever. Patients with cancer can choose to engage in chemotherapy, radiation therapy, immunotherapy, hormone therapy, surgery, or a combination of these treatments.
Pop-culture depictions of cancer can make it seem like once someone has a diagnosis, they become devastatingly sick and unable to function in everyday society. But this is far from the truth.
Crilley said: "With a lot a patients, you would never notice anything wrong with them. For example, some patients may be on an oral agent for chronic myelogenous leukemia. If you saw them, they usually don't have any hair loss, they usually don't have any weight loss. They're working full time, exercising, and living a normal life."
Much of this can be credited to developments in treatment.
Crilley added: "With the advances in oncology treatments over the last few years, the unprecedented number of new FDA-approved drugs, and the advent of immunotherapy, which has different side effects than chemotherapy, a lot of patients are now doing so much better and are not sickly and feeling terrible."
Duma said one of the goals of oncology is to help people transition to life after they've received a cancer diagnosis. That includes breaking stereotypes about the disease and changing the way we talk about people who have been diagnosed.
"We say 'patients with cancer' [instead of 'cancer patients'] because it's important to not define people by the disease," Duma said.
In age of internet health gurus, there are many blogs and websites that say consuming natural herbs or supplements can cleanse the body of cancer cells or prevent a person from ever getting it. Duma said "there is no scientific data that 100% proves there is any one thing a person can take that can get rid of or prevent cancer."
She added that some natural remedies can hinder the cancer treatment patients are already receiving, saying, "A lot of patients tell their doctor they are taking supplements, and those supplements may interact with their chemotherapy."
Still, this doesn't mean patients with cancer need to totally avoid these treatments, because they can help them in other ways.
"The most important thing [for patients] is to talk to their doctor," she said. "Some patients may get benefits from taking certain supplements. For instance, I know there are some patients who have taken a supplement that help them with the nausea from chemotherapy. But more research is needed on that."
Duma said, "Right now, more people go to the doctor for kidney stones than tumor pain."
But patients can have pain related not to a tumor but to the effects of cancer in general, Duma said.
She said: "Fatigue is often the most common symptom, but it all depends on what the cancer is doing. If a tumor is in the lungs, a patient may have shortness of breath. If it metastasizes to the bones, they can have bone pain. If the tumor is in your liver, you may turn yellow. It's about where the tumor is and how it spreads. That determines which symptoms patients present."
Medical knowledge and treatment of different cancers have significantly improved over the years, leading to an increase in the number of people who survive cancer and live for years after complete remission.
"It's clear that it's not automatically a death sentence in 2019 due to the fact that there are so many advances in technology, detection, in prevention of cancer, and in screening," Crilley said. "And I think there's more awareness by patients and their caregivers of what to look for and when to seek medical attention. So many patients now are being cured, and we're looking at trying to use the treatment that's effective to cure the disease, and at the same time to minimize short- and long-term toxicities for the patient."
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