THE BIG QUESTION: Why is it so hard to cure cancer?

A cancer cell in a patient’s lung divides to form two new mutated cells © Science Photo Library

A huge new study has revealed that what we know as ‘breast cancer’ is in fact at least ten different diseases. Could this be a clue to why curing cancer has been such a struggle?

The human body is made up of billions of microscopic cells, which constantly divide to create copies of themselves. This division and self-replication is the essence of life itself: the process occurs in every organism, from starfish to oak trees. Without it humans could not reproduce, grow or even survive.

But sometimes, this life-giving process becomes a killer. Chance mutations in the DNA of a cell can make it start reproducing much too fast. Soon, thousands of cells share the deadly mutation. A cancerous tumour is born.

Christened ‘the emperor of all maladies’, cancer is the UK’s second biggest killer. A ‘cure for cancer’ is one of medicine’s holy grails. But despite decades of intensive research, a solution remains elusive.

Cancer’s resilience is partly a product of its very nature. A cancerous tumour is formed from the same biological matter as the organism it destroys, so anything which kills cancer is likely to damage its host as well.

Many chemotherapy drugs, for instance, target fast-growing cells. But healthy cells in the hair and blood breed fast as well. So chemotherapy causes hair loss, as well as many other distressing side effects – some of them very serious.

Now, British researchers have discovered that the condition known as ‘breast cancer’ is in fact at least ten diseases. This raises a further, knottier problem. There are hundreds of cancer types overall. And each one responds to different treatments. Worse, even cancers of the same type vary hugely from case to case.

So there are many types of cancer, and limitless variations within each type. But perhaps most dismayingly of all, there is even diversity within each tumour. A single cancer can contain a huge variety of cell types – and these cells are evolving all the time.

Even when an effective treatment for a particular cancer is found, some cells are likely to be resistant. While parts of the tumour are vanquished, tougher cells will survive and reproduce.

As one expert says: ‘A tumour is not a single entity. It’s an entire world.’

Perspiration not inspiration

So is a ‘cure for cancer’ even possible? Probably not – at least not with one ‘magic bullet.’ A ‘cure for cancer’ specialists say, is little more plausible than a ‘cure for virus.’

Yet there is hope. Survival rates for cancer have been steadily rising for decades, to the point where more than half of those diagnosed now live for at least five years. The science is advancing impressively every year.

Even this new study, though daunting, is important. Medics can now focus their research more finely, tackling one disease at a time. This is how cancer must be fought: not with one great swipe, but a thousand well-aimed cuts.

You Decide

  1. Would we be better off focusing our efforts on diseases that are easier and less expensive to cure?
  2. Are people too eager to generalise about complicated things like cancer, or is this the only way to really understand them?

Activities

  1. Write the dialogue for a scene in a film or play in which someone has just been diagnosed with cancer.
  2. Research cell reproduction and draw a diagram showing how it works.

Some People Say...

“Cancer only gets this sort of attention because it affects people in rich countries – we should focus more on diseases like malaria and TB.”

What do you think?

Q & A

How much hope is there for people suffering from cancer already?
It really does depend on the details. Some cancers kill only a small proportion of their victims in developed countries – testicular cancer has a 95% survival rate, for instance. Others are more deadly. But since no two tumours are alike, only a doctor who knows the specific case in detail can guess at the patient’s chances.
Is there anything I can do to prevent cancer?
All cancers are genetic. You cannot (yet) change the genes you are born with, so there is no sure method of prevention. However there are things that help your chances: eat healthily, don’t smoke and try to avoid sunburn.

Word Watch

Organism
Any individual and distinct life form is an ‘organism.’ Some organisms, like bacteria have only one cell. We have trillions, each of them adapted for a particular role in the body.
Second biggest killer
After heart disease.
Holy grails
Sought and quested after by the knights of King Arthur’s round table, the Holy Grail in Arthurian legend is the cup of God. Only the bravest and most virtuous can find the grail, but those who do win eternal life. The ‘holy grail’ now metaphorically refers to any treasured objective that is difficult to achieve.
Magic bullet
The phrase ‘magic bullet’ comes from a German folktale. In the story, a man meets the devil and is given bullets that mysteriously hit any target he aims at. It is used to describe any medicine that kills a disease-causing organism without harming its host. Most ‘magic bullets’ are antibiotics.

Subjects

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