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A review of the funding and knowledge gaps in prostate cancer research across the UK: 2020
TREATMENT Spreading to bone About 80% of men who die from prostate cancer will have secondary tumours in bone 4. Although there is some existing knowledge, the process of how prostate cancer spreads, or metastasizes, to bone is not fully understood. However, it is clear that it plays a significant role in disease mortality. Metastasis to bone can also cause bone pain and significantly reduce quality of life. There is a clear need to better understand how prostate cancer spreads to bone, and how this can be successfully prevented and treated.
What patients tell us In our 2019 grant call, the patient panels felt that bone metastasis should be a high priority.
Androgens, hormone therapy, and keeping hormone therapy working Prostate cancer is fed by male hormones such as testosterone, collectively known as androgens, which act via the androgen receptor (AR). Androgen deprivation therapy (ADT), a mainstay of prostate cancer treatment, essentially starves the tumour by blocking the AR or otherwise reducing androgen function. However, its use is limited as many cancers develop resistance, and manage to avoid being killed by ADT. Androgen Receptor Variants, or ARVs, are short forms of the AR, which have lost the external part of the AR which normally acts as a switch. As a result, they are thought to be always on (‘constitutively active’) and ADT can’t switch them off. In response to ADT, prostate cancers increase both normal ARs and ARVs. More research, including more studies in men, is needed to establish the larger role of ARVs in prostate cancer and resistance to hormone therapy, and how to successfully treat a tumour which relies on ARVs.
What patients tell us Our research projects on keeping hormone therapy working are popular with patients. They tell us that as many patients, especially those with advanced cancer, are treated with hormone therapy, it gives them hope of having more time.
Side effects All treatments for prostate cancer, especially prostate cancer which has spread to other places in the body, have side effects which can be life-changing. Erectile dysfunction and incontinence are the most common. Others can include nausea, bowel disturbances, and osteoporosis. Finding ways to prevent or mitigate the side effects of current treatments would have an enormous impact of quality of life for many people affected by prostate cancer.
What patients tell us Although every patient’s experience of side effects is different, they and their families consistently tell us that the physical and psychological side effects of their disease and its treatment have had a significant affect on their life.
Who should have surgery? Radical prostatectomy (RP) is the surgical removal of the entire prostate gland. It is estimated that between 13 and 42 men may need to undergo RP, and are at risk of experiencing side-effects, for every one life saved by it 6. Over-treatment such as this is costly both financially and in terms of quality of life for men who undergo unnecessary treatment. Active surveillance (AS) is the process of monitoring prostate cancer without making
any radical intervention to treat the cancer. While it avoids the harm associated with over-treatment, more knowledge is needed on which patients are suitable for AS and which are at risk of more aggressive disease and who require immediate treatment. Around 43% of men drop out of active surveillance protocols in the first five years 6, a small proportion of whom opted for treatment despite no signs of their disease getting worse, suggesting a lack of confidence in the system.
Immunotherapy This type of treatment aims to harness the power of the immune system to treat cancer. Immunotherapies have been effective in a small number of other cancers, and while there are some indications that immunotherapy has potential to treat prostate cancer, many trials so far have had disappointing results. This is likely due to the ability of prostate cancer tumours and the area around them (the ‘tumour micro-environment’) to suppress the immune system.