Cancer myths and questions • 12 May 2025

Why is cancer so hard to cure?

With so much money spent on trying to find cures for cancer, many people ask us, why is there not a cure yet? And will cancer ever be curable? Here we explore the reasons why cancer is especially hard to cure, but also the reasons to be hopeful.

Why is there no cure for cancer? The complexity of the disease:

Cancer is not one disease - it's an umbrella term for more than 200.

Each broad cancer type has many sub-types, and they all look and behave differently because they are different on a genetic and molecular level. Because cancer arises from our own cells, each cancer can be as different and diverse as people are.

Not only that, but myriads of mutations exist.

Cancer is caused by the appearance of faults in our DNA, called mutations, which cause cells to grow uncontrollably. Underlying the 200+ different cancers are a myriad of different genetic mutations. Every cancer is caused by a build-up of mutations and, as the cancer progresses, more and more different mutations accumulate.

This means two people with the same broad type of cancer can carry individual sets of mutations. This means a drug that works for one cancer patient might have absolutely no effect for another.

Cancer cells within a single tumour are not identical

Different cancer cells in the same tumour can have different mutations. Although an original set of mutations caused the cancer to appear, over time new mutations can appear and cause the cells to change.

That means treatments may kill all of one type of cell in a tumour, while others that are resistant survive the treatment and grow in number again. This is also how, if not spotted early, cancer spreads to other places in the body – a new mutation gives a new line of cancer cells the ability to survive in the bloodstream and move elsewhere.

Treatments can eventually stop working

The genetic mutations that cancer cells acquire over time mean that the cells change the way they behave. This can be an incredibly difficult problem during treatment because the mutations can lead to cancer cells developing resistance to a treatment over time - a patient may have success with a treatment for some time, then find that it stops working.

If that happens, the patient will then have to be put on to a different treatment – but again, the cancer could develop resistance to the new drug. There also may not be any alternative options if that treatment fails.

Cancer cells are really good at staying alive

Normal cells have 'safety’ mechanisms in place that stop them from growing or dividing too much, and every day our immune system kills off cells that could have become a problem. Cancer cells have lost these mechanisms and can hide from the immune system, so they survive and continue to grow out of control. Cancer cells can develop an arsenal of tricks to avoid being killed.

Additional FAQs

Why is cancer particularly hard to treat in later stages?

The more that cancer grows and spreads the harder it is to stop. Traditional cancer treatments – chemotherapy , radiotherapy and surgery – have saved millions of lives but they don’t work on all cancers or all patients.

In later stages of cancer, it spreads, or ‘metastasizes’ to other organs. These metastatic cancer cells are different to the original tumour cells, and are often less responsive to treatments. It can also be harder to eliminate all cancer cells when it spreads.

Why do cancer treatments sometimes stop working?

What makes cancer different from other diseases that have a cure?

For some diseases, researchers have been able to work out what the cause is and how to cure it. The development of the COVID-19 vaccines have saved millions of lives since the global pandemic.

Cancer is more complex. There is not one cause or one clear way to cure cancer. Plus cancer cells are really good at staying alive.

Will there ever be a cure for cancer?

Our Curestarters often ask us, “Is cancer curable?” While there won’t ever be one single cure for cancer - because it is not a single disease and doesn’t have a single cause - new breakthroughs will help us find new cures for the 200+ types of cancer that exist.

The discovery research that our Curestarters support is vital, because it allows us to turn the best ideas into new ways to prevent, diagnose, and treat all types of cancer.

What progress is being made toward finding new cancer treatments?

We can’t cure what we don’t understand. Curestarter researchers are working worldwide to better understand how cancer behaves so that we can find new ways to stop it in its tracks.

From exploring the link between ageing and cancer to stopping childhood tumours being so aggressive, you are funding some of the most innovative cancer research happening around the globe.

It is only through research that we will stop the suffering caused by cancer and reach a day when no life is cut short by the disease.

And we have already made great progress. Thanks to research, cancer survival rates in the UK have doubled since the 1970s, and one in two people diagnosed with cancer can now expect to survive for 10 years or more after their diagnosis.

But there is still a lot of work to be done, and it is not just the cancer researchers who are making these breakthroughs happen. That is why we need your support more than ever. None of this vital work would be possible without the support of Curestarters like you.