PATCH (PR09)

What was this study about?

Prostate cancer needs the male hormone testosterone to grow. Treatments therefore lower the level of testosterone, which helps to control the growth of the cancer. Unfortunately, standard hormone treatment with injections or implants can cause a range of long-term side effects. They may cause bones to thin and become more likely to break. Many patients experience frequent and distressing hot flushes.  

An alternative way of lowering testosterone is through the use of patches, referred to as transdermal oestradiol. These patches allow oestradiol (a type of hormone) to pass through the skin. Reducing testosterone this way might be able to treat the cancer in a similar way as standard hormone therapy without causing some of these side effects.

The PATCH trial tested transdermal oestradiol in two groups of patients:

1. Patients where the prostate cancer has not spread beyond the pelvis but is at higher risk of doing so.
2. Patients where the cancer has spread further around the body (metastasised).

What difference did this study make?

The results from the first group of patients have now been analysed and published. These showed that transdermal oestradiol was as effective as the standard treatments at controlling the prostate cancer, but with less hot flushes and reduced fractures in patients treated with the patches. There was no difference in the rates of cardiovascular disease, but there was more breast tenderness and swelling in the patients treated with transdermal oestradiol. Overall, patients in the PATCH trial treated with transdermal oestradiol had a better quality of life than those receiving standard treatment.

PATCH publication in the NEJM journal.

The results from the second group of patients – those with metastatic disease at their diagnosis of prostate cancer – are expected later in 2027. In the meantime, transdermal oestradiol could be a choice for patients particularly concerned with minimising hot flushes and maintaining bone health. Patients more concerned with breast tenderness and swelling might prefer to choose standard options. Oestrogen patches are not currently licensed for the treatment of prostate cancer but are on several hospitals’ formularies to facilitate this.

Guidance for Healthcare Professionals: Transdermal Oestradiol for Prostate Cancer Treatment

Download clinical guidance (pdf)

Please note: Patients using oestrogen patches as their Androgen Deprivation Therapy (ADT) should not be prescribed Tamoxifen (sometimes used to prevent breast swelling and tenderness caused by some of the prostate cancer treatments). Our experience with PATCH is that Tamoxifen stops the oestrogen patches from suppressing testosterone production and makes it ineffective for treating prostate cancer.

We did not see any breast cancer in men treated with oestrogen patches, but don’t have any specific data in patients with known mutations in the BRCA genes and would recommend that these patients have LHRH analogues/antagonists as their ADT.

Dr Duncan Gilbert (Innovative Clinical Trials Unit) at the 2024 ASCO Conference: 

 

Professor Nick James (Institute of Cancer Research) at the 2025 GU ASCO Conference:

 

Type of study

Randomised trial

Contact details

mrcctu.pr09@ucl.ac.uk

Who funded the study?

PATCH is funded by Cancer Research UK.