Precision Medicine is getting very popular in terms of the future of medicine and managing the rising costs of treatment. Maybe one of the most expensive therapeutic areas at the moment is cancer treatment. 

What is precision medicine in the context of anticancer therapies?

Precision medicine will give opportunity cancer cells to be attacked based on patient’s specific genetic footprint and also ability to predict the future clinical course. Genomic differences between cancers of the same histological type can vary to the point that there are no two tumour with identical genetic profile. This could be used to predict how the cancer will behave in the future – if it will not spread and therefor does not need any treatment or if it will spread which organs and systems could potentially affect. 

What are the current trends in oncology drug development?

More and more novel anticancer therapeutics are designed to interact with targets which have specific genetic profile. The development of gene sequencing technologies allows more patients to have a level of genetic profile that will allow selecting specific anticancer therapy. Good example here would be HER2 positive breast cancer therapy which gave a new and better treatment opportunity for patients with HER2 positive breast cancer. 

Drug resistance as a limitation

The very nature of cancer allows tumours to be highly adaptable and often they can become resistant to new therapies. Sometimes single gene mutation can trigger resistance to a whole new class of anticancer therapeutics. In such cases optimal treatment cannot be predicted before the mutation occurs. For example, resistance to anti-EGFR treatment could lead to failure of targeted drugs, hormones and chemotherapy. This is another example of the high flexibility and adaptability of the cancer cells.

Small cancers which do not have that level of instability can be classified genetically and targeted successfully. This will give some treatment predictability.  

How population size affects the tumour mutations? With increase of patients population the chances for mutations increases too and also the chance for developing resistance. 

Another interesting effect is that tumours with high mutation rates could be in disadvantage and better target for precision medicine than tumours with moderate mutation rate. Therefor the predictability will be better in small tumours with moderate mutation rates than in larger tumours with high mutation rate that are unstable.

Analysis of the genetic stability of different organs and systems could allow better predictability where the metastasis may occur. Often metastases are not triggered by primary tumour cell but by small subclones. 

In conclusion resistance is easier to predict than tumour progression and reoccurrence. While precision medicine has its future there are still many limitations based on lack of information and the complexity of cancer as a disease area. 

Source: Cancer Evolution and the Limits of Predictability in Precision Cancer Medicine

Author: Olga Peycheva

Olga is a clinical research professional who has been working in clinical research since 2005. She has extensive experience in clinical research in Eastern and Western Europe. 

Originally published on 7 July 2017