a definition
Precision medicine is a part of personalized health, and draws on novel technologies to find therapeutic strategies adapted to a patient’s history and genetic data.
All patients are unique by way of their genome, their environment, their lifestyle and the diseases they have come across during their lifetime.
The terms ‘genomic medicine’, ‘personalized health’, ‘personalized genomic medicine’, ‘predictive medicine’, ‘individualized medicine’ and ‘molecular medicine’ are also frequently used for this novel form of medicine.
Seeking out the differences…
Precision medicine examines a patient’s DNA to find genetic variations (mutations) that may be contributing to the development of a disease and/or influencing the response to a given treatment.
…to offer personalized treatment.
Once the mutations have been indexed and interpreted, appropriate drugs can sometimes be found for a given patient.
In the field of oncology, precision medicine is already part of reality.
Tumour analysis at the molecular level (DNA and protein) is paving the way to a more refined diagnosis sometimes helping to choose custom treatment.
CHARACTERIZING CANCER TODAY…
Today, cancer is characterized not only by the organs and tissues that are affected – or by the types of cells found in a tumour – but also by the genetic variations (mutations) present in the cancer cells’ DNA.
Indeed, by altering certain proteins, mutations can contribute to the development of cancer and/or influence the response to a given treatment.
...THANKS TO NOVEL TECHNOLOGIES
Examining DNA to pick out mutations is now possible thanks to the rapid technological advances that were made in the 2000s while the human genome was being sequenced.
A novel type of medicine – known as ‘precision medicine’ – now complements the more traditional approaches of medicine.
Such an analysis requires a multidisciplinary approach involving the fields of oncology, pathology, biology, genetics and bioinformatics.
The MTB gathers professionals from a variety of backgrounds including oncologists, pathologists, biologists, geneticists and bioinformaticians.
Every week, the board examines the cases of patients suffering from cancer, particularly those who are not responding to standard treatments.
PATIENT CARE, STEP BY STEP
With their consent, the oncologist transfers a patient’s medical record to the MTB along with pre-existing samples taken from the tumour.
Cells from the tumour and the surrounding tissues are analysed in a molecular pathology laboratory.
The tumour’s DNA is sequenced and the mutations indexed.
Bioinformatics analysis is used to interpret the mutations. Existing information on the altered proteins is found in databanks, or inferred thanks to bioinformatics predictive tools or molecular modelling.
The MTB hands their report over to the patient’s oncologist. In the best of cases, the report includes recommended treatment.
Custom treatment can be offered to the patient, which involves targeting specifically altered proteins found in the cancer cells.
Since its foundation in 2016, the MTB has taken care of several hundred patients. In 2017 and 2018 for example, over 700 people benefited from the MTB’s expertise.
Actionable mutations were found in about 30% of the patients. In other words, these patients were able to benefit immediately from adapted treatments.
Other treatments can also be recommended even if there are no ‘actionable’ mutations. In all, on the basis of mutations found in their cancer cells, tailored treatments were recommended to about 50% of the patients. Clinical trials were recommended to over half of the patients. An off-label treatment (i.e. a drug usually prescribed for something else but potentially effective) was recommended to 46% of the patients.
No specific treatment could be recommended to certain patients. However, since the emergence of novel technologies, advances in the fields of molecular biology, bioinformatics and medicine never cease to evolve and the chances of surviving cancer increase continuously.
And yet, sometimes there is no adequate treatment. Why?
Mutations found in the tumour may (still) be unknown, in which case no drugs can be suggested. On the other hand, though various mutations may already be known – because they have been found in other patients worldwide – no specific treatment has (yet) been found.
Why? The reasons are manifold and simply reflect the complexity of the mechanisms involved in cancer cell evolution.
Mutation heterogeneity is one reason. Every tumour has its own genetic personality, and it is not an easy task to grasp each of its characteristics.
Tumours evolve not only with time but also, and especially, with treatments given to a patient. Cancer cells sometimes develop their own resistance to a given treatment despite the fact that the chances of success are deemed high.
A treatment’s effectiveness depends not only on the tumour’s ‘genetic personality’ but also on certain genetic characteristics of the patient – not to mention their life style and history.
Nevertheless, precision medicine is a source of true hope, and it is only by considering each patient as a unique human being that chances of recovery will increase.