
Why Do So Many People Get Cancer?
Season 2 Episode 31 | 5m 45sVideo has Closed Captions
Some cells break all the rules.
Some cells break all the rules.
Problems playing video? | Closed Captioning Feedback
Problems playing video? | Closed Captioning Feedback

Why Do So Many People Get Cancer?
Season 2 Episode 31 | 5m 45sVideo has Closed Captions
Some cells break all the rules.
Problems playing video? | Closed Captioning Feedback
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Learn Moreabout PBS online sponsorship"The American people, through their elected representatives in Congress, have determined to wage unremitting warfare against cancer.
This disease has been on the increase in recent years.
It now ranks second among the causes of death."
We start life as a single cell; specifically programmed to grow and divide to eventually become the 37 trillion or so cells that make up the human body.
Each cell is a perfect clone of the cells that came before it.
And it takes just one rogue cell for this perfect system... to fall apart.
Cancer starts with the uncontrolled growth of a single cell.
This cell has a genetic mutation; it's a nonconformist that breaks all the rules of cell growth.
Normally cells need signals to grow, they stop growing if they come into contact with other cells and after a certain number of cell divisions.
But in a way, cancer cells are immortal.
They don't stop growing and their potential to replicate is limitless.
The causes of cancer can be inherited or triggered by our environment - things like smoking, a poor diet, lack of exercise and exposure to the sun and other types of radiation.
Some viruses can damage your DNA, like Human papillomavirus, and lead to cancer.
Sometimes, we can't identify a specific cause.
And it seems that so many people get cancer - Statistics say it's more common now than it ever has been.
Some people claim that cancer is an ailment of modern society.
But really?
What's going on?
First of all, cancer isn't a single disease, there are more than 200 types of cancer.
And it is common: Today in the United States, almost 40% of people will be diagnosed with cancer at some point in their lifetime But it hasn't always been so prominent.
The first recorded case of cancer came from the ancient Egyptian physician Imhotep, around 2625 BC.
In one of his cases he found "bulging masses on the breast, spreading, similar to an unripe fruit; cool and hard to touch."
In The Emperor of all Maladies, oncologist Siddhartha Mukherjee writes this "could hardly be a more vivid description of breast cancer."
Abdominal cancer and other tumours have also been found in Egyptian mummies, and a large bone tumour than pierced the skin was found in the preserved body of a young women of the Chiribaya tribe in the Atacama desert.
Up until a few hundred years ago, it was rare to find records of cancer.
There were other concerns - the plague, influenza, tuberculosis and smallpox, to name a few.
Cancer was around, but it was rare because people didn't live that long and practitioners couldn't perfectly define it.
But by 1900, cancer was the eighth most common cause of death in the United States.
By 1950, life expectancy had increased by 21 years and cancer was second, behind heart disease, as the leading cause of death-the same as it is today.
In ancient times and up until recently, people simply didn't live long enough to get cancer.
It's much more common in older people - your risk of developing cancer increases with age.
For example, men from 0-49 years old have a 1 in 304 chance of getting prostate cancer.
By the time they hit 70, it's a 1 in 9 chance.
But throughout this increase in diagnoses, there's also a big increase in survival rates.
In 2013 the American Cancer society reported that death rates have fallen by 20% from their peak 20 years prior.
For this we can thank progress in cancer education, screening, diagnosis and treatment.
Still, many cancers can be prevented.
in 2010, almost 1.5 million of the 8 million cancer deaths around the world were caused by tobacco smoking.
And more than 20% of cancer worldwide is related to people being overweight, obese, physically inactive or having a poor diet.
So why do so many people get cancer?
It's a combination of increased life expectancy and our lifestyle factors; worldwide smoking increased in the 20th century and there's more cases of obesity than ever before.
A 19th century surgeon once wrote cancer is "the emperor of all maladies, the king of terrors".
But it's not the incurable terror it once was.
A side effect of cancer becoming more prevalent is that awareness has too - prevention, early detection and treatments are the best they've ever been.
When speaking of the Human Genome Project, former US President Bill Clinton said, "It is now conceivable that our children's children will know the term cancer only as a constellation of stars."
We can be hopeful, but cancer is certainly still with us, and perhaps it always will be.
But the same drive that led us to map and explore those stars will surely, one day, mean that cancer is not some inevitable end to ever-longer lives, but a challenging stop along the way.
See you next week.


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