Is cancer curable? Increasingly so, experts say – 5 reasons to be optimistic as big developments in treatment and diagnosis help more patients survive
- Cancer, while still a leading cause of death, is becoming more curable with advances in treatment, from surgery to chemotherapy, and better drugs and testing
- Vaccines, such as for HPV, are playing a part, as is AI in aiding research. On World Cancer Day, doctors explain some of the tools being used to defeat cancer
An online news search for “recent” developments in the treatment of cancer returns 263,000 hits. It’s an area that is evolving – and fast.
A leading cause of mortality worldwide, cancer accounted for nearly 10 million – or nearly one in six – deaths in 2020. But it is less feared than it once was because there are so many more effective treatments than before.
Today it’s over 50 per cent, a figure which McAleer believes will rise to 85 per cent in the next generation.
On World Cancer Day, February 4, cancer specialists describe some of the reasons for optimism about beating cancers of all types, including recent advances in treatment and research.
1. Stronger cancer treatment pillars
Surgery, to slice out tumours, now includes minimally invasive and robotic techniques.
New methods of radiotherapy – using radiation to kill cancer cells or slow their growth by damaging their DNA – have been introduced. They include intensity modulated radiotherapy, in which radiation beams are customised and shaped to match the cancer, while the intensity of each beam can be varied.
These advances, Cheng says, primarily help to reduce adverse effects and complications.
Advances in systemic cancer therapy – particularly in chemotherapy and immunotherapy – have been drastic, he says. These don’t just help prolong lives, they maintain quality of life and elevate cure rates for patients with early cancers.
In the late 20th century, Cheng says “chemotherapeutic agents (the drugs taken to kill cancer cells) were our main systemic weapons” but they were not very efficient and carried significant side effects. They were toxic to cancer cells, but also to healthy cells.
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At the turn of the millennium the era of targeted therapy began.
“We discovered that many cancers are driven by activating genetic mutations. By targeting these driver mutations, we can control the growth of cancer cells, and obtain impressive response rates of more than 50 per cent (compared to the 20 to 40 per cent usual response rates of chemotherapy) while minimising damage to normal cells,” he says.
The response rate indicates whether the treatment is having the desired effect in stopping cancer’s spread.
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2. New weapons to treat cancer
Now, “antibody-drug conjugates (ADC)” are in the treatment pipeline. Cheng describes them as being composed of a “cytotoxic agent which can directly kill cancer cells, and an antibody which can target cancer antigens on the surface of cancer cells”.
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“The antibody helps to deliver the deactivated cytotoxic agent to specific cancer cells where the cytotoxic agent is activated and exerts its lethal effect, so that normal healthy cells are much less affected.”
Although still in its early stages, cancer patients have responded well to ADC in clinical trials.
Dr Rupal Mistry, senior research information manager at Cancer Research UK, says the challenge with cancer is that its cells are unpredictable.
“They can rapidly produce many copies of themselves and [develop] resistance to treatments. Targeting the mechanisms which allow them to do this is an excellent way to stop cancer cells from growing, but it’s difficult.”
One promising treatment in development is AOH1996, named after Anna Olivia Healey, a girl from Indiana, in the United States, born in 1996 who died at nine years old after battling neuroblastoma, a rare cancer that develops from immature nerve cells.
Hong Kong Integrated Oncology Centre clinical oncologist Dr Michael Cheung Ming-chee explains that this experimental anticancer medication targets a cancerous variant of proliferating cell nuclear antigen (PCNA) – a protein that, in its mutated form, is critical in DNA replication and repair of all expanding tumours.
The drug is still in its early stages, but if successful, it could be revolutionary for cancer patients.
Radiotherapy continues to be honed for more effective delivery. Flash-RT is a radiotherapy treatment in the development stage. Cheung describes it as “a technique involving the delivery of ultra-high-dose-rate radiation. We’re talking about the application of 1,000 times the usual dose rate”.
There is, however, “a long way to go before it gets into the clinical treatment stage”, he says.
3. Cancer diagnostics and prevention evolve
It’s not just cancer treatment that is making great strides forward – it’s also preventive measures and diagnostics.
Vaccines are an example. Cheung explains how these work. “Unlike traditional vaccines that aim to prevent a disease from recurring, therapeutic cancer vaccines train the patient’s immune system, enabling T-cells (lymphocytes, a type of white blood cells) to patrol the body for cancer cells and destroy them.”
Consider the success of the HPV (human papillomavirus) vaccine, which the US Food and Drug Administration approved in 2006. HPV causes most cervical cancers as well as some cancers of the anus, vulva, vagina, and oropharynx (the bit at the back of the throat including base of the tongue and tonsils).
The vaccine is now on the World Health Organization’s List of Essential Medicines and preapproved vaccines, and is routinely given to girls at about the age of 12. As of 2022, 125 countries include the HPV vaccine in their routine vaccinations for girls, and 47 countries also do for boys.
Since its introduction, it has successfully eliminated almost all cervical cancer in women born since September 1995. According to the US Centres for Disease Control and Prevention, this vaccine could prevent more than 90 per cent of cancers caused by HPV.
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4. Uncovering pre-cancer clues
Professor Patrick Tan, senior vice-dean for research at Duke-NUS Medical School in Singapore and a professor in the school’s cancer and stem cell biology programme, recently published a study in the journal Cancer Cell.
In Singapore alone, stomach cancer is the fourth leading cause of cancer deaths in men and the fifth in women, claiming 300 to 500 lives annually.
Stomach cancer was the sixth commonest cancer in Hong Kong in 2021, with 1,306 new cases, and 634 deaths in 2022. Patients experience no or only mild symptoms in the early stages; in later stages, treatment may be difficult at best and too late at worst.
The earlier we detect a cancer, the higher the chance that we can cure it
Tan’s study was inspired by the success of population screening in countries with high rates of gastric cancers – Japan and South Korea – “which have led to improved outcomes through early detection”.
An important step in the start of gastric cancer, he says, is intestinal metaplasia (IM), a “premalignant condition” which causes a change in the cells of the stomach lining that can present with symptoms like acid reflux.
Individuals with IM cells face a six-fold increased risk of developing stomach cancer.
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His team’s genetic profiling identified 26 specific genes which may play a role in the transition from normal to IM cells. IM affects 3.4 per cent to 23.9 per cent of the population, “with higher incidence rates in East Asian and South American regions”, Tan says.
5. Growing role of AI
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In one study, AI detected 20 per cent more cancers than were found using conventional methods with less false positives, and an almost 50 per cent reduction in radiologists’ workload.
Speed is of the essence in uncovering and treating cancer. The global market size of AI in the diagnosis and treatment of the disease is forecast to grow from US$1.2 billion in 2023 to US$9.16 billion by 2031.
Cheung would most like to see the development of new tests. “The earlier we detect a cancer, the higher the chance that we can cure it,” he says.
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Traditionally, he said, imaging (CT, PET and MRI scans), endoscopies, and tumour markers are commonly used, but these methods can be limited by “low accuracy, high cost – and invasiveness”.
6 Less invasive, cheaper testing
Liquid biopsies, Cheng says, could pave the way to better, faster, cheaper, less invasive testing.
A liquid biopsy is a test done on a sample of blood to look for cancer cells from a tumour or for pieces of DNA from tumour cells that are in the blood.
Waiting rooms of cancer patients used to be full of the hopeless dying, an oncologist commented recently. Now, with better treatment and better management, they are full of the hopeful living.
