Saving lives with better treatments

For some low-risk, slow-growing cancers, aggressive treatments may not offer any benefits right away and can lead to more negative impacts on quality of life than the cancer itself. Research supported by CCS pioneered an approach called active surveillance, which balances a person’s quality of life with keeping their cancer under control. Under active surveillance, low-risk cancers are carefully monitored and only treated it when it becomes high-risk.

CCS-funded researcher Dr Laurence Klotz first introduced the approach to treating people with low-risk prostate cancer. Prostate cancer is the most common cancer among Canadian men, and in many cases, this cancer is slow-growing and does not require aggressive treatments. Aggressive treatments can lead to negative side effects that dramatically reduce a person’s quality of life. In a groundbreaking clinical trial that began in 1995, Dr Klotz and his team showed that active surveillance is safe for people with low-risk prostate cancer with 10- and 15-year survival rates of 98% and 94%, respectively.

Today, active surveillance has become the standard of care around the world for those with low-risk prostate cancer, helping millions manage their cancer while living life to the fullest.

The success of active surveillance in prostate cancer has inspired researchers to study its potential in other areas. In a first-of-its-kind Canadian study, CCS-funded researcher Dr Annie Sawka and her team are looking at whether this is an effective option for early stage, low-risk thyroid cancer. The current standard of care for these cancers is surgery to remove all or part of the thyroid, followed by lifelong thyroid hormone treatment. If Dr Sawka’s study is successful, it could spare thousands of people from surgery and a lifetime of hormone replacement therapy while managing their cancer safely.

In 1958, CCS-funded researchers Dr Charles Beer and Dr Robert Nobel discovered the chemotherapy drug vinblastine after isolating it from the Madagascar periwinkle. Today, the drug is on the World Health Organization’s List of Essential Medicines in recognition of its importance in treating a number of different cancers including, most commonly, Hodgkin lymphoma.

Chemotherapies like vinblastine are a mainstay of cancer treatment. While some of these drugs were discovered decades ago, CCS-funded researchers today are finding new ways of combining them to maximize their benefits and move the needle for some of the most difficult-to-treat cancers.

For example, researchers from the CCS-funded Canadian Cancer Trials Group (CCTG) took part in an international clinical trial that showed a new chemotherapy drug combination called mFOLFIRINOX can delay relapse and extend life for people with pancreatic cancer. With a 5-year survival rate of just 8%, pancreatic cancer is the 3rd leading cause of cancer death in Canada, highlighting the urgent need for new treatment options like this one.

Another CCTG-led international clinical trial found that adding a chemotherapy drug called temozolomide to a shortened course of radiation therapy reduced the risk of death by 33% in older adults with gliobastoma, an aggressive brain tumour. Importantly, the researchers also showed that this new treatment approach did not compromise quality of life, allowing people to live life to the fullest.

Some cancers, like breast and prostate cancers, are driven by hormones and can be treated with hormone-blocking drugs. Research supported by CCS has led to critical new insights about how these treatments should be used to maximize both their effectiveness and a person’s quality of life.

For prostate cancer, hormone therapy is often used to slow or stop tumour growth but it can lead to serious side effects like hot flashes, urinary problems and impotence. A clinical trial led by the CCS-funded Canadian Cancer Trials Group (CCTG) found that an intermittent course of hormone therapy, where people stop taking the drug for periods of time, is just as effective as continuous therapy. More importantly, people on intermittent hormone therapy experienced fewer side effects and enjoyed a higher quality of life. 

In another influential study, CCS-funded researchers Dr Kim Chi and Dr Daniel Khalaf looked at a new generation of prostate cancer hormone therapies and determined the most effective order in which the drugs should be given. Their results showed that giving the 2 drugs in this specific order helped delay cancer progression by an average of 4 months in people with metastatic castration-resistant prostate cancer, giving them more time with their loved ones. 

In addition to treating cancer, hormone therapies are also used to help prevent cancers from coming back. This is the case for post-menopausal women with early breast cancer, who typically receive hormone therapies for 5 years after completing their initial treatment. A trial led by CCTG found that extending the treatment from 5 to 10 years reduced the risk of cancer coming back by 34%, helping more people stay cancer-free for longer.

Immunotherapies are one of the most exciting areas of cancer research. They seek to harness the power of a person’s own immune system to target cancer.

Groundbreaking discoveries made by CCS-funded researchers in the 1960s and 1980s paved the way for many of the cutting-edge immunotherapies being tested and used today. These include Dr Ernest McCulloch and Dr James Till’s discovery of stem cells, which led to the development of bone marrow transplants to treat blood cancers. Dr Tak Mak’s discovery of the T-cell receptor gave us a new understanding of how the immune system recognizes and fights cancer.

Here are some of the ways that CCS-funded researchers are continuing to develop and improve cancer immunotherapies:

• Surgery to remove a tumour can be life-saving but it can also weaken the immune system and allow remaining cancer cells to spread. Dr Rebecca Auer and her team showed that using a vaccine to boost the immune system before surgery can help prevent cancer spread after the operation, improving outcomes for people undergoing cancer surgery.
• Cancer-killing viruses are a double threat to tumours. They can infect cancer cells directly to destroy them and amp up the immune system’s ability to target the tumour. Dr John Bell and his team have conducted critical studies to expand our understanding of how these viruses work and how they can be modified to be more effective. They have demonstrated the potential of creating custom designer viruses to target pancreatic cancer and of combining these viruses with standard chemotherapies to treat breast cancer.
• Brain tumours are often difficult to treat because the blood-brain barrier, which effectively prevents many treatments from reaching the tumour. Dr Michael Taylor and his team discovered that they could bypass this barrier and administer a type of immunotherapy called CAR T-cells directly to the tumour via the cerebrospinal fluid, the liquid that surrounds the brain and spinal cord. Their results showed that this approach was effective at not only treating primary tumours, but also tumours that had come back and spread. These promising findings are laying the foundation for future clinical trials that could help children with brain tumours live longer, fuller lives.

There will never be a single, one-size-fits-all approach to treating cancer because cancer is not a single disease with a single cause. It’s over 100 different, shape-shifting diseases which means there isn’t one target, there are multiple moving targets.

Thanks to advances in research, we can now tailor cancer treatments to the unique genetic profile of each person and their tumour. This means that people will receive the treatment that is most likely to work for them and be spared the side effects of treatments that would likely not work.

Here are some ways in which CCS-funded researchers are making precision medicine a reality for people with cancer:

• A clinical trial conducted by the CCS-supported Canadian Cancer Trials Group found that for 7 in 10 women diagnosed with a common type of early stage breast cancer, hormone therapy alone was just as effective as both hormone therapy and chemotherapy in preventing the cancer from coming back. These women were identified as being at medium risk of cancer relapse based on their tumour's genetic profile. These practice-changing results will spare tens of thousands of people with breast cancer each year from chemotherapy’s side effects, enabling them to live more fully without affecting their chances of staying cancer-free.
• Another CCTG-led trial identified a specific genetic signature that could predict which people with metastatic colorectal cancer would benefit from an immunotherapy drug called cetuximab, providing a much-needed treatment option for these individuals.
• Dr Kim Chi and Dr Alexander Wyatt are leading a first-of-its-kind clinical trial to test a new precision medicine treatment strategy for metastatic prostate cancer. The researchers are looking at whether they can use the genetic profile of each person’s tumour to determine which drugs would work the best for them. By personalizing treatments from the outset, this strategy could reduce time spent on treatments that are unlikely to work and ensure that people receive the most appropriate treatments at the earliest possible opportunity.

From new technologies to new ways of delivering radiation, CCS-funded researchers have had an outsized impact on improving radiation therapies.

In 1951, CCS-funded researcher Dr Harold Johns developed a new radiation technique using a radioactive element called cobalt-60. Dubbed the “Cobalt Bomb,” it was the most effective form of radiation therapy at the time and revolutionized the field. After the first patient that Dr Johns successfully treated, cobalt-60 would go on to help an estimated more than 70 million people with cancer worldwide, including many here in Canada.

Cobalt-60 is still used today, but newer forms of radiation have gradually replaced it. Thanks to the efforts of CCS-funded researchers, we have also advanced our knowledge about how to deliver radiation to maximize its benefits while minimizing unwanted side effects.

With the support of CCS, Dr Timothy Whelan and his team showed that radiation therapy given in larger doses over a shorter time period was as effective as conventional radiation in reducing the risk of breast cancer recurrence. This new approach, called hypofractionated radiation therapy, means that people with breast cancer can receive their treatment in 3 weeks instead of 5, making it more convenient for them and less costly for the healthcare system.