Is This The Future Of Cancer Therapies?
Dr Doris Chow, M. D (USM) FRCR Clinical Oncology, (Manchester)
20th February 2019
Precision oncology is the science of specifically designing a treatment to target each cancer individually. Access to the latest technology and in depth understanding of tumour biology will enable a widening of the therapeutic window in cancer treatment. This may come in the form of combined modalities such as radiotherapy and systemic treatments such as targeted therapy and immunotherapy. With the vast information available, researchers and clinicians are looking into ‘interpreting’ these data to design a specific treatment with clinical significance for an individual patient. It is hoped that this will pave the way to the new era of oncology; for better outcomes and a potential ‘cure’.
Cancer does not discriminate. Young vs old, male vs female, smoker vs non-smoker, rich vs poor, obese vs skinny; everyone is at risk of developing cancer in their lifetime. However, it has been shown that certain cancers occur more frequently in a particular patient group, certain cancers behave more aggressive or responds better to a specific treatment modality. Although we are nowhere near from using this information to prevent most cancers, we can now improve the outcomes of certain cancer patients based on therapies designed for each cancer individually.
‘Chemotherapy‘ is a scary word and causes a lot of anxiety for patients. Chemotherapy is designed to kill rapidly dividing cells in our body such as cancers. Unfortunately, it is not target specific and healthy cells are also ‘killed’ along with it, causing side effects. The normal cells are able to recover making the effects from chemotherapy mostly transient and temporary. It is undeniable that for most cancers, chemotherapy remains the gold standard for treatment at the moment. With new findings and breakthroughs, we now know that the treatments for certain cancers such as kidney, lung, melanoma, liver and thyroid are more effective with the use of targeted agents and immunotherapies. Can this be the future of other cancers too?
Cancer is so diverse and versatile. It has the ability to mutate and adapt before, during and after treatment. But what if we can determine the specific ‘vulnerability’ of each cancer at any point of time and attack that? This is what personalised and precision oncology aim to achieve.
Access to molecular testing and next generation sequencing (NGS) now allows us to have a better ‘genetic’ understanding a cancer. This is a technique where a tumour is ‘broken down’ into its basic DNA structure and the sequencing will enable us to have detailed genomic information. With this technology, we will be able to see what genetic mutations the tumour harbours. This is not routinely done, but NGS may helpful for patients with rare cancers or for patients whose cancers does not respond and behave as it normally would. There are numerous clinical trials and researches now that utilises this information to treat patients based on their genetic makeup rather that the standard therapies.
Although promising, there remains endless challenges in applying the concept to cancer treatment at this stage. The complex biology of cancers makes it difficult to predict its response to therapy despite identifying the mutations and flaws in its DNA. Until now, data form NGS of persons with advanced cancers indicate fewer than 10% have mutations that have a clinical impact from current available therapies. This concept is appealing and remains a possibility, but until that day comes, we will continue to hope for a better future in cancer therapies.