Bioengineers aim to improve treatment for prostate cancer

Dr Hayley Reynolds is the first researcher at the ABI to be leading research focussed on a condition that affects only men, prostate cancer, the second-most commonly diagnosed cancer in Kiwi men and the most common cancer diagnosis in men world-wide.

Her research is working towards more personalised radiotherapy treatment for prostate cancer patients and an improvement in how patients’ response to radiotherapy is assessed after treatment.

The current standard treatment for prostate cancer involves delivering a uniform dose of radiation therapy (high-energy particles to destroy or damage cancer cells) to the entire prostate gland, regardless of where the tumour is located in the prostate or its biology.

This does save lives but can also have serious side effects on a patient. Moreover, up to 50% of prostate cancer patients can have their cancer return within ten years of treatment.

Treatment for prostate cancer, like all cancers, is informed and limited by the technologies used in diagnosis and treatment.

Radiation therapy for prostate cancer is currently planned using CT (computed tomography, a computerised x-ray imaging procedure) which shows anatomical structures inside the body including the prostate. However, standard CT imaging cannot show where a tumour is located within the prostate or the biological characteristics of that tumour.

This information is important; the biological characteristics of a tumour, such as its cellular density, aggressiveness, and hypoxia (when tumours are deprived of adequate oxygen) are known to influence the effectiveness of radiotherapy treatment.
 

But multiparametric MRI (mpMRI) can provide more comprehensive information than CT about both tumour location and its biology, and this could be used to significantly improve treatment, says Dr Reynolds.

“For instance, international clinical trials have shown the benefit of using information from mpMRI to plan treatment by giving an additional ’boost’ dose of radiation to the tumour in addition to the standard dose of radiation given to the whole prostate,” she says.

There are many questions to investigate, she adds, including, for instance, how mpMRI could be used to plan for more precise and effective radiotherapy treatment in initial treatment but also to identify recurrence of prostate cancer as early as possible.

Identifying recurrent prostate cancer currently depends on prostate-specific antigen (PSA) testing. This is problematic, because while elevated levels of the PSA protein can indicate cancer the protein is produced by both cancerous and noncancerous tissue in the prostate; elevated PSA levels can be caused by other benign conditions.

MpMRI has shown potential to identify recurring cancer earlier and more accurately than current PSA testing, as well as show where in the prostate the cancer has recurred, which is something PSA testing is unable to do says Dr Reynolds.

“Which means that if patient shows they are not responding to treatment, then their radiotherapy treatment plan could be adapted, or other treatment options considered.”

Dr Reynold’s research is also exploring how mpMRI could allow for biologically targeted radiotherapy, or BiRT. This would allow for a more personalised non-uniform dose of radiation based on patients’ tumour location and its biology identified from mpMRI.

“Which could include delivering higher doses of radiation that are confined to regions of the prostate shown to be harbouring disease, and a lower dose to where the tumour has not been found, limiting damage to surrounding tissue” she says.

“Biologically targeted radiotherapy would be relevant for all solid tumours, not just prostate cancer, but also head and neck cancer, breast cancer, lung cancer, brain cancer, pancreatic cancer and more.”

We have the technology, but we need more information about how to identify the biology of tumours using the technology, and how that biology will influence response to treatment.

Dr Reynolds has recently received funding from the Centre for Cancer Research, for a study in which she aims to identify potential imaging biomarkers, a measurable indicator of the severity or presence of disease, using mpMRI.

In this study participants who are being treated with radiotherapy at Auckland City Hospital will be scanned with an mpMRI before and after treatment.

Changes in patients’ mpMRI scans will be analysed using machine learning methods and compared with blood-based measures of treatment response (including PSA and measures of hypoxia), to identify imaging biomarkers which may indicate early treatment response. The study will be carried out in collaboration with researchers at the University of Sydney, with whom Dr Reynolds aims to run larger clinical trials in future to validate imaging biomarkers identified in this study.

“Our overarching aim is to personalise treatment for patients, so that it's not a one size fits all approach, and ultimately all patients receive the best treatment possible.”