The Prostate Cancer Biomarker Conversation Caregivers Should Know How to Start

For many women caring for a husband, partner, father or loved one with advanced prostate cancer, there comes a moment when the conversation suddenly becomes much more technical.

The oncologist starts talking about biomarkers. Someone mentions PSMA (prostate-specific membrane antigen). A PSMA-PET (prostate-specific membrane antigen positron emission tomography) scan is ordered. Genetic testing enters the discussion. New treatment possibilities emerge, often accompanied by unfamiliar terminology and difficult decisions.

It can feel overwhelming. But understanding the basics of biomarker testing can help caregivers ask better questions, participate more confidently in treatment discussions and advocate effectively for the person they love.

“Patients are often overwhelmed and have difficulty thinking of questions important for their care, and this tends to be even more common for men than women,” says Dr. Walter Stadler, chief clinical officer at City of Hope Cancer Center Chicago and a medical oncologist specializing in genitourinary cancers. “It is thus critical for loved ones and caregivers to always make sure they fully understand treatment options.”

What Is a Biomarker?

The term “biomarker” sounds complex, but doctors use biomarkers every day to better understand a patient’s cancer.

“A biomarker is any (usually quantitative) test that can provide information about the patient and their disease,” Stadler explains.

Importantly, biomarkers aren’t limited to blood tests.

“These can include laboratory tests, imaging tests and even information from patient-completed surveys,” he says.

Doctors use biomarkers to help diagnose disease, estimate prognosis, predict whether a treatment is likely to work and monitor how a patient is responding to therapy. As prostate cancer treatment becomes increasingly personalized, biomarkers help guide decisions that may not have been possible even a decade ago.

Why PSMA (Prostate-Specific Membrane Antigen) Matters

One of the most important biomarkers in advanced prostate cancer is PSMA, or prostate-specific membrane antigen.

“Prostate specific membrane antigen (PSMA) is a protein that is typically expressed on the surface of the majority of prostate cancer and normal prostate tissue, but not in the vast majority of other tissues or organs,” Stadler says.

That makes PSMA useful for both imaging and treatment.

“It has increasingly been used as an ‘address’ that can be used to deliver therapies and imaging contrast agents specifically to prostate cancer,” he explains.

In simple terms, PSMA helps doctors locate prostate cancer cells more precisely and, in some cases, target them more directly with treatment.

Understanding the PSMA-PET Scan

Many caregivers first hear about PSMA when a doctor recommends a PSMA-PET (prostate-specific membrane antigen positron emission tomography) scan.

This imaging test uses a tracer that attaches to PSMA proteins, allowing doctors to identify where prostate cancer cells may be located throughout the body.

“A PSMA-PET scan can provide information on where the cancer is located and how much prostate cancer may be present in an individual patient,” Stadler says.

The scan can sometimes detect disease that conventional imaging misses, helping physicians better understand the extent of cancer.

However, Stadler notes that PSMA-PET scans are not necessary for every patient.

“There are clinical scenarios in which the scan may be far less useful,” he says. “For example, in patients for which a PSMA-PET scan will not add additional information beyond what can be gleaned from standard tests.”

For caregivers, an important question is whether the scan’s results would actually influence treatment decisions.

How Biomarker Testing Can Affect Treatment

For many families, the most important question is whether biomarker testing could open the door to additional treatments.

“The vast majority of prostate cancers are PSMA-positive,” Stadler says.

However, some advanced cancers lose PSMA expression over time.

“Patients whose tumors don’t express PSMA are much less likely to benefit from PSMA-targeted therapies,” he explains.

“For those patients whose cancers do express PSMA, a standard therapy is available, and a number of additional PSMA-targeted therapies are in development,” Stadler says.

Biomarker testing can therefore help determine treatment eligibility and identify potential clinical trial opportunities.

Biomarkers Are Only One Piece of the Puzzle

One misconception many families have is that biomarker results automatically determine the next treatment step.

In reality, they are only one factor among many.

“Like all medical tests, many of our biomarkers are imperfect,” Stadler says. “They may help with decision making, but they are rarely the sole arbiter of a clinical decision.”

A patient’s symptoms, overall health, treatment history and quality-of-life goals remain critical considerations.

Questions Caregivers Should Ask

Because oncology appointments can feel rushed, and emotionally charged, caregivers often play a vital role in ensuring important questions get answered.

Consider asking:

• Would biomarker testing provide useful information at this stage?
• Has a PSMA-PET scan been considered?
• How would the results affect treatment recommendations?
• Are there targeted therapies that may be appropriate?
• Should genetic testing be performed?
• Are clinical trials available?
• What additional testing might help guide future decisions?

Stadler notes that genetic testing is frequently overlooked.

“A specific biomarker that tends to be overlooked in prostate cancer are genetic tests to determine whether there is a hereditary predisposition to prostate cancer and a separate test to assess the molecular make-up of the cancer itself.”

Those results may affect treatment planning and could have implications for family members as well.

Remember: You’re Part of the Care Team

Learning about biomarkers, imaging tests and treatment options can feel like taking on a second job. But effective advocacy doesn’t mean becoming an expert in every medical detail.

Dr. Linda Dolin, medical director of The Sylvia Brafman Mental Health Center, encourages caregivers to remember that advocacy should support — not replace — the patient’s voice.

“Women often have to perform a delicate balancing act, advocating on behalf of the men in their life while also making sure that this voice and autonomy are respected in medical settings,” she says.

She also encourages family members to view themselves as collaborators rather than sole decision-makers.

“I would encourage them to view themselves as part of a team comprising the doctors, hospital staff, other family members and more, rather than an isolated individual who is solely responsible for their health,” Dolin says.

You don’t need to become an oncologist or memorize every biomarker before the next appointment. What matters most is understanding enough to start the conversation.

Knowing the basics of biomarkers, PSMA and PSMA-PET scans can help caregivers ask informed questions, participate more confidently in treatment discussions and ensure that every appropriate option is being considered. In a disease that often requires complex decisions, that kind of advocacy can make a meaningful difference.