A prostate cancer diagnosis can leave a person with many decisions to make. Cancer stage, PSA levels (Prostate-Specific Antigen), biopsy findings, and overall health all help doctors plan treatment. But in some cases, another piece of information can make the treatment plan more specific: the cancer’s genetic profile.

Genetic testing can identify changes in genes involved in prostate cancer risk and tumour behaviour. Some of these changes may also indicate whether a person could benefit from certain targeted treatments. This is one reason genetic and tumour testing has become an important part of personalised prostate cancer care.

Key Takeaways

• Genetic testing can identify inherited changes, while tumour testing looks for changes within cancer cells.
• BRCA1, BRCA2, ATM, PALB2 and mismatch repair genes are among those that may be assessed.
• Genetic findings can help identify patients who may be suitable for certain biomarker-directed treatments.
• A genetic result should always be interpreted alongside the cancer stage, previous treatment and overall health.
• Genetic counselling can help patients understand inherited findings and their possible relevance to family members.

What does genetic testing look for in prostate cancer?

There is no single genetic test that is right for every person with prostate cancer. Doctors may use two different approaches:

• Germline testing looks for inherited genetic changes. These changes are present in nearly every cell of the body and can sometimes be passed from a parent to a child.
• Tumour or somatic testing looks for genetic changes that have developed in cancer cells. These changes usually occur during a person’s lifetime and are not necessarily inherited.

The difference is important. A genetic change found in a tumour does not automatically mean that it was inherited. If tumour testing identifies a change that could be linked to inherited cancer risk, doctors may recommend germline testing to clarify this.

When might genetic testing be recommended?

Genetic testing may be considered based on the type and extent of prostate cancer, family history and a person’s previous cancer history.

Testing may look at genes such as BRCA1, BRCA2, ATM, PALB2 and CHEK2, as well as genes involved in mismatch repair, including MLH1, MSH2, MSH6 and PMS2. The specific genes tested depend on the individual’s situation and the type of test being performed.

A finding that appears to be inherited can also affect biological relatives. Depending on the result, family members may be advised to discuss their own genetic risk with a healthcare professional.

How can genetic results influence treatment?

The important part of genetic testing is not simply finding a genetic change. It is understanding whether that change matters for treatment.

Some prostate cancers have alterations in genes involved in homologous recombination repair (HRR), a process that helps cells repair damaged DNA. BRCA1 and BRCA2 are two important genes involved in this pathway.

When doctors find certain clinically relevant DNA-repair alterations, they may consider PARP inhibitors, a group of medicines that interfere with cancer cells’ ability to repair DNA. These medicines are used only in appropriate patients and depend on the specific genetic alteration and other clinical factors.

Doctors consider genetic results alongside the cancer stage, previous treatments, and the person’s overall health. Testing therefore does not replace the usual assessment. Instead, it can add another layer of information when doctors decide which treatment options may be appropriate.

Abiraterone acetate is another medicine used in certain forms of advanced prostate cancer. It reduces the production of androgens, hormones that can support the growth of prostate cancer cells. A medicine containing abiraterone acetate, such as Xbira 250mg, may be prescribed as part of an appropriate treatment plan.

A genetic test does not, by itself, determine whether abiraterone acetate is suitable. The choice of treatment depends on the individual’s cancer characteristics, previous treatment, symptoms and overall health.

What if the genetic test finds a variant of uncertain significance?

Genetic reports do not always give a straightforward positive or negative answer.

A report may identify a pathogenic or likely pathogenic variant, meaning there is strong evidence that the genetic change has clinical significance. However, it may also identify a variant of uncertain significance (VUS).

A VUS means there is currently not enough evidence to know whether the genetic change affects health or cancer risk. It should not automatically be treated as a harmful mutation or used on its own to change cancer treatment.

This distinction is easy to miss but important for patients. A genetic test containing a VUS does not necessarily mean that a person has an inherited cancer-causing mutation.

What happens after the test?

The genetic report is only one part of the treatment discussion.

Doctors may consider the result alongside PSA trends, imaging, biopsy findings, cancer stage, previous treatments and overall health. If a tumour test identifies an inherited genetic change, doctors may recommend confirmatory germline testing.

Genetic counselling can also help patients understand what a result means. This can be particularly helpful when a result may affect family members.

Conclusion

For advanced prostate cancer, tumour testing may sometimes be repeated or reconsidered as the disease changes. Cancer cells can acquire new genetic changes over time, so a tumour’s molecular profile may not remain exactly the same throughout treatment.

The aim of personalised care is not to treat a genetic result in isolation. It brings together genetic information with the rest of the patient’s medical picture, helping the healthcare team make treatment decisions appropriate for that individual.

Disclaimer: This article is intended for general health information and should not replace medical advice. Genetic testing and prostate cancer treatment should be discussed with an oncologist, urologist or qualified genetic counsellor. Do not start, stop or change any medicine based only on information in this article.