* The action of immunotherapy drugs on some cancers, such as lung and melanoma, has already altered prognosis of the disease.
* However, this type of treatment, which stimulates the patient’s immune system against cancer, still lacks the same success in breast cancer.
*These are some of the unknowns yet to be resolved.
Immunotherapy, also known as biological therapy, is a type of cáncer treatment which stimulates the body’s natural defences, with the aim of fighting cancer. It employs substances produced by the body, or made in a laboratory, to improve or restore the function of the immune system. Immunotherapy can function in the following ways:
• To stop or delay the growth of cancer cells.
• To stop cancer from spreading to other parts of the body.
• To help the immune system function better in recognising and destroying cancer cells.
Cancer treatment with immunotherapy, a field in which HC Marbella is a leader, is already being used successfully in certain types of tumour, such as those of the lung and melanoma. As Dr. Pérez explains, response rates fluctuate between 20% and 30% with the use of antibodies which block control points in the immune system. But, all things considered, these levels have not been achieved in breast cancer and immunotherapy is still not an alternative to conventional chemotherapy.
What is clear is that breast cancer is very heterogeneous. The three large subtypes: positive hormone-receptor, HER2+ and triple negative tumours, have little in common. The three distinct conditions each have a different prognosis and treatment.
Furthermore, breast tumours are also different in terms of their immunogenicity (the ability to activate the immune response) lagging behind lung tumours and melanoma.
But amongst them, triple negative (hormone receptor and HER2 negative) is the best subtype candidate. These tumours have the greatest capacity to activate the body’s defences, presenting more genetic mutations and making them more receptive to future targeted therapy and immunotherapy treatments.
For this reason immunotherapy research is focused on this type of cancer, although research is also being undertaken in HER2 and positive hormone-receptor tumours.
“Immunotherapy does not have the same benefits for everyone and in breast cancer we still have to learn to select the patients who will really benefit from it”, explains the oncologist, noting, “the latest research is geared to better investigating why the response rate is not high, to see whether this is due to the heterogenicity of the tumour, and whether there are certain cell populations within the tumour which are more resistant to immunotherapy than others.” The latest projects will analyse this approach in triple-negative breast cancer, a breast cancer for which there is no latest generation treatment.
In this regard, the properties of the tumour subpopulations which avoid the immune system will be studied, with a translational approach. In other words, this information will be used to design therapeutic targets which can take advantage of the molecules that are already being used to treat other types of tumours with immunotherapy. “The aim is to find specific treatment configurations and adjust them for breast cancer,” markers will also be sought to enable the response to treatment to be predicted.
Still no conclusions can be drawn, as there are still gaps in knowledge: Will immunotherapy be more effective in breast cancer in combination with chemotherapy/radiotherapy rather than as monotherapy? How can we select patients who will respond to immunotherapy, by PD-L1 expression or with other biomarkers? Is it better to use immunotherapy as first line treatment? Research will be revealing.
* Speak to us about your case. In Spain, our Oncologists and Specialist Consultants are leaders in their field and recognised throughout Europe. They work together as a coordinated team, in multidisciplinary committees, dedicated to obtaining the best results for you.
* In the CANCER DETECTION section of our website you can find information on preventative measures for this and other types of cancer.
Sources: 
Dr. Diego Pérez
Oncology Unit at HC Marbella.
Cancer.net / ASCO: American Society of Clinical Oncology
March 13, 2019
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