Our medical knowledge has been getting increasingly fine-grained for centuries. Christine Coffey discusses the ways in which this is becoming ever-truer of cancer treatment specifically.
According to the World Health Organisation, cancer is the second leading cause of death, being responsible for 8.8 million fatalities in 2015. We may be improving the standard of life for patients, refining palliative care and providing precious extra days, months, and years with loved ones, but traditional methods of radiation and chemotherapy are falling short of the ultimate end goal of winning our fight against cancer. Nonetheless, some emerging techniques focusing on the principle of conditioning your immune system’s response to cancer cells are gaining momentum, resulting in a more personalised approach to this fight.
Most bacterial, viral, and fungal diseases result from a foreign micro-organism invading the body. However, most cancers differ from this as they typically originate in the body. Cancer is a repair process gone into overdrive, where cells multiply at ever faster rates. The problem with standard chemotherapy and radiation is that you are bombarding these cells and damaging them, attempting to eradicate them like you would any bacterial or viral infection. Some patients respond positively to these treatments and their tumours shrink. Targeted chemotherapy now exists for some cancers, such as chronic myelogenous leukaemia, which results in 100% remission rates. As the oncologist Dr. David Agus suggests, it seems as though trying to beat cancer to a pulp with brute force is not as successful as we would like it to be.
“Simply put, if we can control our immune system and the blood flow supplying potentially cancerous cells, then we are not giving cancer a chance to grow, essentially starving it.”
Tumours grow thanks to a process called angiogenesis, where new blood vessels grow and allow the tumour to take over the surrounding blood supply, which provides nutrients and other essentials for further growth of the tumour. Some particularly aggressive forms of cancer take over major blood supply routes to vital organs to the point where removing them surgically would be fatal. Such tumours are inoperable, and at that point all hope is placed on radiotherapy and chemotherapy, which aim to shrink the tumour as much as possible. Without a blood supply and without angiogenesis, tumours are benign and generally very small. Simply put, if we can control our immune system and the blood flow supplying potentially cancerous cells, then we are not giving cancer a chance to grow, essentially starving it.
If all the blood vessels from a single human being were connected end-to-end, they would span the equator twice over. This means a lot of potential sites for tumours to hijack, but fortunately most of these blood vessels are with us from infancy, and there are few special instances in which our bodies manufacture new blood vessels. One of the most important of these is after an injury, when blood vessels form under a scab and all grow towards the damaged area. The body controls this process through an intricate balance of stimulants and inhibitors, so that when new vessels are required, proteins which promote the growth of these vessels (called angiogenic factors) are released and when the area has healed, inhibitors are released.
Judah Folkman researched the effect of naturally occurring blood vessel growth inhibitors and their role in defending us against the progression of cancer. Due to angiogenesis, tumours get the oxygen and nutrients required to grow exponentially, and this network of blood vessels also acts as a transport channel by which cancerous cells migrate to other organs within the body. The research of Dr. Folkman was far from a comprehensive outline of the magic bullet that would put an end to cancer, but it put the research of a very promising field of oncology in the right direction, and it shows great potential for certain cancers.
“If all the blood vessels from a single human being were connected end-to-end, they would span the equator twice over.”
Proteomics is also an emerging field where digital snapshots of all the proteins in a patient’s body are created in another approach to tackling the disease. Not dissimilar to comparing the DNA of different people, overlapping patterns indicate common protein expressions in different people. This means that in a clinical trial where one patient reacts positively to a treatment and another does not, the protein expressions can be compared. This could lead to more precise targeted treatments, personal to the protein make-up of the patient and how they are likely to react.
Since the 1850s, cancers have been categorised based on the location of the tumour. With the development of more targeted anti-bodies, the tumours would be more accurately classified based on the proteins they express. According to a report by the industry group PhRMA, almost 250 immuno-oncology medicines and vaccines were in development in 2017. Thus, many checkpoint inhibitors are being given the green light by the FDA.
“Since the 1850s, cancers have been categorised based on the location of the tumour.”
In a press statement following the 2016 census, the Central Statistics Office reported that “Ireland’s population has been getting steadily older since the 1980s.” According to the report, almost 40% of the population are over the age of 44, with those aged 65 years and over demonstrating the largest increase in population since 2011 – a 19.1% increase. These are the most at-risk groups for developing cancer – in developed countries, prevalence of disease increases with the average age of the population. It is early days yet, but Immuno-oncology shows great promise in the future of cancer treatment.