Cancer causes and treatments over time, from aging to surgery : Short Wave : NPR

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A view of a close up of a lung x-ray of a cigarette smoker in an undated photo.

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One of the first recorded mentions of cancer appears in an ancient Egyptian text from around 3000 B.C. And although we now know much more about how cancer begins–as a series of mutations in someone’s DNA–it’s a disease people are still struggling to cure today.

Centuries of treatments

Over the centuries, people have using a wide range of things to try to cure cancer — everything from pastes, salts, teas to cauterization and more.

One milestone came in the 1700s when British surgeon Percivall Pott connected cancer to a clear environmental cause. He noticed that chimney sweeps were developing a specific type of cancer after being exposed to soot. The revelation led to a minimum age for chimney sweeps.

But this revelation only showed how one might avoid getting cancer, not how to treat or cure it.

« Cancer was a death sentence. People would not be given a long time to live, » says Mariana Stern, a cancer epidemiologist at the University of Southern California.

She adds that for a long time cancer was often treated with surgery. But as scientists and physicians realized that any cancer cells left behind — missed by surgery or hiding elsewhere in the body — could grow back later, they started looking for complementary treatments.

Around the turn of the 19th century, physicians discovered that radiation could treat cancer. Swedish physicians Tor Stenbeck and Tage Sjogren separately cured their respective patients of skin cancer using x-rays. Around the same time, many radiologists who used their own skin to determine proper radiation dosages developed leukemia. But in some cases, radiation could also cause it. So radiation is still used as a cancer treatment today — in a much more targeted way.

Chemotherapy came several decades later, in the mid-1900s. It gave doctors a way to kill cancer cells that surgery or radiation couldn’t reach. The idea was that certain drugs targeted dividing cells — a hallmark of cancer cells.

Today, overall cancer survival is much higher than it was even a few decades ago. Given that there are over one hundred types of cancer, that success isn’t across the board.

A plurality of cancers

« Each cancer type has its own unique characteristics, » says Stern. « So I think the chances of finding one treatment or one way to cure what we call cancer is impossible. »

Instead of a universal cure, researchers are looking to improve prevention and treatment for each type of cancer, which includes understanding how a cancer develops in the first place. Although around five to ten percent of cancers can be genetic, most come from random mutations in our genetic code that our cells don’t fix. One mutation can lead to another, which can result in cancer.

« There are multiple environmental and even internal carcinogens that we’re exposed (to) or that can increase the amount of mutations that we accumulate over the amount that we’re already accumulating because of random chance, » says Stern.

The list of carcinogens is long and includes everything from sun exposure to tobacco use, diets high in processed and red meats, being physically inactive — and even viruses and bacteria. All of these carcinogens can lead to different types of cancer, which may require different types of treatment.

But Stern says the number one carcinogen in her book isn’t something anyone can control: age.

« As we age, our cells deteriorate and accumulate more mutations, » says Stern. « We live so long nowadays, pretty much one in two people are going to get cancer across their lifetime. »

But she adds that she doesn’t want the message to sound so gloomy. « It’s not like we’re doomed; just because you get old, you will have cancer. I think a lot of it can be modified by paying attention to these other factors that we know cause cancer and are correlated with age because they accumulate over time. »

Treating cancer today

In recent years, cancer survival has gone up — in part because researchers and clinicians are turning toward more personalized treatment approaches.

« One patient with breast cancer might be treated one way and another patient with breast cancer might be treated a completely different way based on the characteristics of that tumor, » says Stern.

For example, one of those breast cancer patients may undergo a treatment originally developed for lung cancer because that’s what the breast cancer tumors respond to best.

Another reason for moving toward personalized treatments is that cancer doesn’t affect all people–or populations–the same. One big area of Stern’s research is studying differences in cancer rates and outcomes in different Hispanic communities. Nationally, research lags for this population. The same can be said for American Indian, Alaska Native and African-American populations, which are also underrepresented in cancer studies.

« This introduces a disparity because a lot of the drug therapies have been designed among patients of European background, » Stern says, and adds, « if we don’t consider that, we may not be treating them with the best drugs that those tumors are going to respond to. »

One exciting new treatment option involves harnessing a patient’s own immune system to attack cancer cells. « This has proven to be extremely effective because our own immune system has a mechanism by which they can surveil our body, » says Stern.

Even with cutting edge advancements in cancer treatment technology, Stern says treatment access is still a big problem.

« I think the main innovation that needs to happen is that there needs to be a commitment that every single cancer patient will get access to the best treatments that are available to them. And that’s not happening now. »

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This episode was produced by Berly McCoy, edited by Rebecca Ramirez and fact checked by Brit Hanson. Gilly Moon was the audio engineer.