When we hear the word “cancer”, most of us immediately think of pain, chemotherapy and a long, difficult and emotionally-taxing journey. But in recent years, medical breakthroughs have used an element of our own immune system to fight cancer, and it’s been a miraculously effective method! First and foremost, though, what really is cancer? What’s immunotherapy? And what’s stopping every patient from accessing this treatment?
Visual by Sabena Bhadri
What is cancer?
In general terms, cancer refers to a collection of diseases caused by abnormal cells that multiply uncontrollably. Normally, our cells die and are removed when they become old and useless, but cancer cells are unusually resilient and simply take over everything around them. This means that they also steal nutrients and energy from normal cells, leading to the sickness that we associate with cancer. Whilst many cancers form solid tumours, some can also exist in the blood. In order to fight cancer, our immune systems need to recognise these criminals of the body.
@ cancer cells
What is immunotherapy?
Most of our immune system is made up of white blood cells, which form part of our blood. There are many sub-types of white blood cells – some already exist as part of our innate immune system (always producing the same immediate response), and others are adaptive (adapt to attack foreign things). Immunotherapy is a way of treating cancer by manipulating our adaptive immune system so that it can eradicate cancerous cells. In particular, it often involves T-cells, a type of white blood cell that scans for cellular abnormalities and infections.
Recent developments in immunotherapy
Well, it’s not exactly that recent. In 2018, James P. Allison (from the University of Texas) and Dr Tasuku Honjo (Kyoto University) were jointly awarded the Nobel Prize for Physiology or Medicine for their separate work in the 1990s which saw the development of immunotherapy. In particular, they showed that certain proteins on either cancer cells or T-cells prevent our bodies from attacking cancer. So, if we block these proteins, the immune system can properly recognise cancer cells as foreign and attack them. Consequently, we've developed immunotherapy drugs that suppress these proteins and they’re now widely used to treat many different types of small cancers.
Artistic interpretation of immune system attacking foreign cancer cell
There are many branches of immunotherapy. One form of immunotherapy that’s recently had increasing media exposure is called CAR T-cell therapy. Our T-cells are meant to patrol our body for signs of foreign parts or infections, including the formation of cancer. But cancer cells can either very cleverly disguise themselves as healthy cells (with the proteins mentioned above), or sprout too many antigens (a foreign substance that stimulates an immune response) that the T-cells can’t effectively attack. In CAR T-cell therapy, billions of T-cells in patients’ own blood are re-engineered to contain the Chimeric Antigen Receptor and turn into CAR T-cells. These receptors enable T-cells to latch onto cancer cells and inject toxins to destroy them. This animation sums up the process pretty well:
CAR T-cell therapy has been especially effective for cancers of the blood, which were often previously regarded as untreatable. It has the potential to save so many lives, but why isn’t every cancer patient accessing immunotherapy?
Drawbacks of immunotherapy
The field of immunotherapy is still relatively new with ongoing research and clinical trials, so procedures such as CAR T-cell therapy aren’t commonly found in public healthcare systems and can be very expensive. As a result, the families of terminally ill patients often have to scrape together every last cent by re-mortgaging houses, selling furniture and setting up crowd-funding pages to help their loved ones access lifesaving treatment that’s often only found in the USA or Europe. Of course, it would seem ideal if every cancer patient could undergo immunotherapy immediately. However, we still aren’t sure about the side-effects and long-term consequences, so these methods are still in development. Some clinical trials have resulted in patients developing autoimmune diseases, meaning that the rebooted immune system attacks itself, even the functional cells.
So, in these early stages of creating what will undoubtedly be a ground-breaking chapter in medicine, cancer patients must continue to wait as researchers determine the overall impacts of immunotherapy.