Has prostate cancer prevalence changed over the past few years?
Dr. Rob Hamilton (RH): The incidence of prostate cancer has been stable over the past five to 10 years. The good news is that the mortality rate from prostate cancer is improving due to advances in treatment.
What treatment advances have led to the improved mortality rate?
RH: There have been significant improvements in prostate cancer treatments over the years. For decades, the mainstay of treatment was to suppress male hormones (androgens) that drive prostate cancer growth. However, eventually the cancer outsmarts the androgen suppression. Around 2012, a new generation of androgen-blocking drugs was discovered, significantly extending survival and often delaying or avoiding chemotherapy.
Another treatment advancement is radioligand therapies. They use antibodies that bind to specific proteins on prostate cancer cells to guide the radioactive pharmaceuticals directly to the tumour. Finally, some prostate cancers have specific genetic mutations which allow genetically targeted therapies such as PARP inhibitors to more effectively kill the cancers and have been proven to prolong survival. We are learning more about how to optimally select patients to receive these therapies.
What are some of the challenges in treating prostate cancer and how do they drive research?
Dr. Mathieu Lupien (ML): One of the critical challenges prostate cancer patients often face is the recurrence of the cancer, about 20 per cent to 30 per cent of men experience recurrence. In recent years, the Prostate Cancer Research Program at PM has made transformative advances in understanding the cancer recurrence and in developing tools to monitor disease progression.
RH: From a patient journey and disease progression perspective, prostate cancer affects patients' quality of life at various stages. Patients can feel anxiety upon diagnosis, even if the cancer is low grade and low stage. When patients undergo radiation or surgical treatment, side effects like erectile dysfunction, urinary incontinence and irritative bowel symptoms can have a life-long impact.
In advanced or metastatic stages, the cancer itself can cause pain, weakness, fatigue, fractures and immobility. Treatments for advanced prostate cancer can also cause side effects such as fatigue, gastrointestinal upset, falls and decreased sex drive.
Describe some of your research progress in understanding prostate cancer recurrence.
ML: Over the past years, my research team has examined how the diversity of cancer cells within a tumour, a phenomenon known as tumour heterogeneity, can favour the progression of prostate cancer. This contributes to the treatment resistance and recurrence as some cancer cells respond to treatment while others allow for the evolution of the cancer into a resistant form.
Using advanced single-cell technologies, we can examine individual cancer cells with incredible precision. It's like taking a high-resolution photograph of a crowd at a hockey game and grouping fans together based on the jerseys they wear, while taking into account their names and numbers on the back. Similarly, the technique allows us to pinpoint many distinct types of cells in a prostate tumour, quantify their numbers and understand their behaviours.
One of our most exciting discoveries is that the diversity of cancer cells lies in how the DNA is packaged differently across cells with different function, a process known as epigenetics. This work that began as part of our "discovery" research efforts has now transitioned into "translational" research, where we aim to match the DNA packaging differences in various cancer cells with new treatment options that could transform prostate cancer care.
What advances have been made in monitoring for prostate cancer progression?
ML: At Princess Margaret Cancer Centre, colleagues have developed non-invasive methods to detect and monitor prostate cancer, such as screening for tumour-derived molecules in urine. There are also efforts on blood liquid biopsies to develop innovative methods for early detection and monitoring treatment response.
The intent is to create tools that can track prostate cancer evolution in real time, using non-invasive approaches. Together, these efforts improve our understanding of prostate cancer biology and can potentially transform how we manage prostate cancer to improve patient outcomes and quality of life.
This story first appeared on UHN News