In an interview conducted remotely due to the pandemic, Dr. Cynthia Ménard, on the other side of the screen, exudes an air of serenity that seems to be a permanent fixture of her personality. This CHUM research centre (CRCHUM) researcher has been awarded a grant totalling nearly $3M from the Canadian Cancer Society and the Movember Foundation to conduct, with her team, a national phase 3 clinical trial in more than 750 patients at risk of advanced prostate cancer.

The goal is to determine whether an imaging technique known as PSMA PET/CT can be more effective in guiding radiation therapy treatments and surgical interventions by providing a more accurate image of the extent of the disease.

The acronym PSMA PET/CT, as barbaric as it may sound, is actually a combination of computed tomography (CT) and positron emission tomography (PET) using a radiotracer targeting the prostate-specific membrane antigen (PSMA). By detecting the presence of a protein —the PSMA— on the surface of prostate cancer cells, this imaging technique is able to locate the spread of the cancer in the body more effectively than conventional imaging techniques.

Dr. Ménard’s clinical trial enters its recruitment phase in November. We talked to this CHUM radiation oncologist and Université de Montréal professor (Department of Radiology, Radio-Oncology and Nuclear Medicine) about the trial.

Q1. What do you hope to accomplish with this major grant?

A. Many studies have already shown the invaluable contribution of PSMA PET/CT in detecting prostate cancer. This is even more true for the new generation of PET radiotracers such as 18F-DCFPyL, familiar to specialists, which we use and can produce with the CRCHUM’s cyclotron. We are now better able to detect cancer sites than by using conventional imaging alone.

However, no clinical trial has yet determined whether the intensification of radiation therapy or surgery, based on the results obtained through this imaging technique, improves treatment efficacy by reducing the rate of prostate cancer recurrence after treatment.

With our randomized phase 3 trial, we will be able to determine whether this therapeutic approach is better than current medical standards and weigh the adverse effects, if any, against the benefits of the intensified treatment. We will also be able to evaluate whether there is an overall improvement in patient quality of life over the long term.

Q2. Why do you believe this trial is important for patients and for the medical practice?

A. This research project follows on a phase 2 clinical trial launched in 2018 at the CHUM. It already showed that patients who had had a PSMA PET/CT scan before their treatment saw an escalation of their radiation therapy: a higher dose or targeting of cancer sites not found with conventional imaging.

For our patients at risk of advanced cancer, there’s no question that we are hoping that our Canada-wide phase 3 trial will show a benefit, which would result in changes in the practice of radiation therapy and surgery. But for now we are just embarking on this adventure.

Over a 3 year period, with the help of other hospitals across Canada, we will recruit 776 patients with high-risk localized prostate cancer who need to undergo curative-intent radiation therapy or surgery. Patients diagnosed with a recurrence of cancer after a prostatectomy will also be able to participate.

Compared to the control group, the participants in the experimental group will receive a PSMA PET/CT scan before their treatment. Based on the results, the doctors will be able to adjust the radiation therapy or surgery in the targeted areas.

Q3. If the results of this trial are conclusive, what impacts will they have on Canadians?

A. PSMA PET/CT is increasingly making its way into clinical practice in Canada and worldwide. However, without conclusive data on the reduction of cancer recurrence rates and improvement in patient life quality, Canadian health authorities (Health Canada, provincial ministries of health, etc.) are unable to decide whether they should reimburse this new imaging technique and offer it to a broader patient population.

We are dealing with this issue of cost-effectiveness and economic analysis in our clinical trial thanks to the expertise of our colleagues at the University of Alberta.

In the years to come, the data from our study will be crucial in evaluating the impact and value of PSMA PET/CT as part of our prostate cancer treatment arsenal.