Many people believe that there will be a single drug or treatment found by scientists that will cure all kinds of cancer. This is, unfortunately, a quite widespread misconception regarding cancer research. Due to the complexity of the disease, the future of cancer treatment lies in a more targeted and personalised approach. Combined knowledge about the biology of cancer and combined effort from physicians and scientists will be needed to find the best way to treat cancer in the future.
When I was little, I was sure that one day there would be a scientist with a brilliant mind that would find the one cure for cancer. Convinced that cancer could be cured, I started studying biology and ended up being a cancer researcher. Over the years I learnt a lot about the complexity of the disease, which has made it impossible to find a single treatment strategy. Even though researchers are not aiming to find one treatment to cure all cancers, some people who are not in the medical field still believe that the single cure for cancer will be found one day. Unfortunately, since this has not happened yet, this general misconception is leading to people losing their hope in cancer research.
Cancer is one of the most complex diseases that we face today. It usually starts as an interplay of different alterations in the genome of a cell. These alterations, termed mutations, lead to changes within the cell that alter their behaviour, shape and function. A cell that has not been dividing for a very long time can suddenly experience a mutation in its DNA that could lead to this one cell dividing in a very rapid manner, making it a cancer cell by definition. Excessive division is only one of the many hallmarks of cancer (1). The way cancer cells evolve in their behaviour and composition is very diverse and can depend on many different factors (1). Due to the complex evolution of cancer cells, various sub-types of cancer can arise in the same tissue and within the same tumour type.
A perfect example of sub-type diversity is one of the most commonly diagnosed cancers worldwide: breast cancer. There is a general consensus about the existence of at least three major subtypes of breast cancer (2). These subtypes are classified according to the expression of receptors (2,3). Receptors are molecules on the outside of a cell that receive signals that are transmitted into the cell, thereby directing a course of action. Specific receptors that can transmit a killing-signal to the cell and are only expressed by certain sub-types can be activated by anti-tumoural drugs. The treatment efficiency and resulting life expectancy of patients with different types of breast cancers therefore varies tremendously (2,4).
Cancer treatment nowadays is already partly personalised and targeted. Tumours are checked for their sub-type classification and then treated with a specific regimen, depending also on the patient’s disease history and situation. As an example, this approach increased the efficacy and survival rates of breast cancer patients dramatically in recent years (5,6). Nevertheless, the main first line treatment strategy for many cancers remains chemotherapy or surgery, and sometimes only after relapse are personalised strategies implemented. Chemotherapy, perceived as a very powerful single treatment against most cancer types, comes with a huge cost in terms of toxicity and other side-effects. There are still many cancer types where these regimens are saving only a very limited percentage of diagnosed patients. Patients can be resistant or acquire a resistance against chemotherapy, or they can experience a relapse after surgery. Therefore, the future lies in a completely targeted and personalised treatment approach, also described as precision medicine.
There are many recent advances in cancer research that have led to successful new treatment strategies and drugs for cancer patients. In 2018, the Nobel prize in Physiology or Medicine was awarded for the findings of two researchers on how to make the patient’s immune system attack cancer cells. These findings have been implemented in the clinics and have been found to work for many cancer types, including melanoma, lung cancer, bladder cancer or colorectal cancer (7). One could consider this a general and less targeted treatment approach as it affects the patient’s immune cells, and not the cancer cells directly. Unsurprisingly however, this therapy has not been proven to work for all cancer types, as many cancer cells manage to evade this targeted attack by the immune system (7,8,9). Researchers are still trying to decipher the underlying mechanisms and reasons for resistance to this therapy in order to be able to give it only to patients who will benefit (7,9).
No matter how people target cancer, it is my informed opinion as a researcher in the field that there will never be one treatment applicable to all types and sub-types of cancer. The general public should still be optimistic and value the advances being made every day. New technologies and fresh knowledge will allow a better characterisation of tumours and make specific targeting easier. Until we find treatment options for all tumours there will still be a lot of hard work, brilliant minds and combined efforts needed, but cancer research and clinical translation is certainly on the right path towards success.
References:
- Hanahan, D., and Weinberg, R.A., “Hallmarks of Cancer: The Next Generation”, Cell, 2011
- Sørlie, T., et al., “Gene expression patterns of breast carcinomas distinguish tumor subclasses with clinical implications”, PNAS, 2001
- Yersal, O., and Barutca, S., “Biological subtypes of breast cancer: Prognostic and therapeutic implications”, World J. Clin. Oncol., 2014
- Carey, L.A., et al., “The triple negative paradox: primary tumor chemosensitivity of breast cancer subtypes”, Clin. Cancer Res., 2007
- Higgins, M.J., and Baselga, J., “Targeted therapies for breast cancer”, J. Clin. Invest., 2011
- Masoud, V., and Pagès, G., “Targeted therapies in breast cancer: New challenges to fight against resistance”, World J. Clin. Oncol., 2017
- Jenkins, R., et al., “Mechanisms of resistance to immune-checkpoint inhibitors”, Br. J. Cancer, 2018
- Seidel, J.A., et al., “Anti-PD-1 and Anti-CTLA-4 Therapies in Cancer: Mechanisms of Action, Efficacy, and Limitations”, Front Oncol., 2018
- Sharma, P., “Primary, Adaptive, and Acquired Resistance to Cancer Immunotherapy”, Cell, 2017
