There have been a couple of articles recently about immunotherapy, both in The Guardian:
- Immunotherapy could stop prostate cancer spreading, trial shows
- Doctors hail world first as woman’s advanced breast cancer is eradicated
OK, the second one is obviously about breast cancer. However, I include it because I think it is relevant, and because it has a longer explanation (with graphics) of how immunotherapy works.
For those who can’t open these links – and let me know if this happens to you – here is my precis of this technique.
- A patient with metastatic cancer has biopsies taken from their tumours, and from the metastases.
- The DNA in these samples is sequenced to see which immune cells contain a carcinogenic mutation.
- Immune cells from the tumours are screened to find those that target the mutations.
- Millions of DNA cells are cultured containing the immune cells that target the mutation or mutations. These “healthy” cells are then injected back into the patient.
This technique avoids any issues with rejection as it is the patient’s own genetic material being injected back into her. It also seeks to address one of the big mysteries of cancer: how a mutated form of DNA escapes the surveillance of the body’s immune system in the first place.
As the second article points out, this particular technique has only been used successfully in one patient. However, more than a third of the 250-odd subjects in the prostate cancer trial were still alive after a year’s treatment, and 10% were showing no further growth in their tumours. (These subjects all had advanced PC.) There are aspects of immunotherapy that are not well understood, such as why only about 20% of PC patients respond to it. Nevertheless, it seems promising. My GP had mentioned immunotherapy to me, when I last saw him, as something to keep an eye on, with the view to participating in a trial. I have since joined a database of patients interested in being subjects in trials of new treatments.
Developments such as this justify the objective of keeping PC patients alive as long as possible. Hardly front page news, I know! But I gather there is a particular strategy to use treatment A, even though it might not halt the cancer, but in order to defer the use of treatment B. The longer it is before all the therapeutic shots have been fired off, the more likely it is that patients can benefit from techniques still at the experimental stage.
I went to a very interesting day, labelled a “community conversation”, about new PC treatments (and general issues in PC) organised by the Peter Mac. I will write that up more fully in the next post.