Treatment is designed to attack only the tumour cells, specific drugs are aimed at a therapeutic target (a known cell abnormality that we can treat).

It is called precision, or personalised medicine, because it finds the tumour’s mutation or abnormality independently of its location.

The same cancer in one person can be treated differently to that in another, depending on the molecular abnormalities.

Tumour cells are different to normal cells, there are some genetic differences. Genes produce proteins which tell the cell how to behave.

Targeted therapy focuses on attacking specific abnormalities, proteins or surrounding tissue which contribute to growth and spread.

• It blocks or deactivates the signals telling the tumour cell to grow or divide.
• It changes proteins so that the tumour cells die.
• It prevents the formation of new blood vessels which feed the tumour cells.
• It prevents the cancer from receiving the hormones required for growth (hormono therapy).

Common molecular targets (mutations) treated with targeted therapy are: HER2, EGFR, RAS, VEGF, ALK, ROS1 and BRAF…

To know the specific drug for your type of mutation there are different tests:

Immunohistochemical (IHC):

• This uses a biopsy.
• A special stain is applied to the specimen. This stain adheres to the protein showing whether there is overexpression.
• It tells us whether the protein is present and the relative quantity.
• In breast cancer it is common to determine the presence of the HER2, ER and PR proteins..

Analysis for fluorescent in situ hybridisation (FISH)

• FISH is a molecular technique which helps us to see if a protein exists through the detection of DNA sequencing in preserved tissue or cells.
• This is a pathology test (biopsy).

Genome platforms

• A test is done using a liquid biopsy (blood sample) or biopsy to confirm the type of gene mutation.
• It provides us with information on the behaviour of certain groups of genes in the face of cancer, their level of activity, including the probability of growth or spread.
• It confirms whether the tumour presents any of the known mutations for which there exists a specific drug.
• Understanding the genetic mutation allows us to personalise treatment, finding the precise drug to act against this mutation.

Do you want to know more about genomes?

There are different types of targeted therapies with distinct mechanisms of action according to the cellular abnormality presented.

Some of the mechanisms of action are:

• To prevent the formation of blood vessels which feed and provide nutrients to the cancer cells.
• To alter normal cellular function so that cancer cells die.
• To block cell signals so that the behaviour of the tumour cells change.

The tumour is studied and assessed to determine therapeutic targets and subsequently apply the appropriate drug.

As each drug is specific for each type of mutation the side effects differ depending on the drug given, each patient will also tolerate them differently.

Some of the symptoms which can develop are:

• • Skin problems: acne, rash, skin irritation and discomfort, sun sensitivity…
  • Problems with wound healing or blood coagulation.
  • High blood pressure.
  • Infertility. In patients who are of child-bearing age it is advisable to preserve fertility before any treatment.

Before your treatment, your oncologist will explain the possible effects of your type of treatment and how they can be palliated.

According to the type of drug it can be given:

• Orally: in the form of tablets or pills. Your doctor will explain how you must take them and how to store the medication correctly.
• Subcutaneously: through injection which is given into the fatty tissue just underneath the skin. Hospital attendance is not required, it can be given at home.
• Intravenously: the drug is given directly into the vein through a needle or cannula. A visit to the day hospital is required so that a specialist nurse can administer the drug.

Your oncologist will consider the treatment regime which is most suitable for you, the tumour and the stage of the disease.

Often this treatment may be given as the only treatment or in combination with chemotherapy, radiotherapy and/or surgery.

All this will determine treatment time.

During your treatment, your oncologist will request different tests to see how your body is reacting to treatment.

These tests often include:

• Physical examination
• Radiological investigations,
• Blood investigations