Is it possible for men to put off treating recurrent prostate cancer?
By C.W. Schmidt, Editor, Harvard Medical School Annual Report on Prostate Diseases
- Reviewed by Marc B. Garnick, MD, Editor in Chief, Harvard Medical School Annual Report on Prostate Diseases; Editorial Advisory Board Member, Harvard Health Publishing
What happens if PSA levels start rising after surgery or radiation for prostate cancer? Up to a third of men treated for the disease will eventually confront this problem. If there’s no accompanying evidence of cancer on imaging scans, then men have what’s called a biochemical recurrence. This means that PSA, the biochemical marker in this case, is flagging the presence of cancer cells that doctors are still unable to see.
Biochemically recurring cancer is asymptomatic, and it can take years for visible metastases to appear. Sometimes men live the rest of their lives with a rising PSA without ever developing metastases.
Now, an ultra-sensitive scanning technology is raising new questions about biochemical recurrence and its management.
Test results have an impact on treatment choices.
This scan highlights the protein known as prostate-specific membrane antigen (PSMA), which is present on cancer cells. A PSMA scan can identify small cancers in the body that are not visible with more conventional imaging techniques like magnetic resonance imaging or bone scans. This condition is now known as (PSMA) + BCR, according to medical professionals.
Doctors base treatment decisions on other factors, such as the rate at which PSA levels are rising, when a man has biochemical recurrence as it is traditionally defined and conventional imaging shows no signs of cancer. If treatment is started, a common strategy is to administer medications that block testosterone, a hormone that promotes the growth and spread of prostate cancer. However, because biochemical recurrence usually proceeds slowly, if at all, doctors may also postpone that treatment.
What happens if a man has both BCR and (PSMA)? After that, things become a little trickier. Many doctors are inclined to treat patients aggressively and quickly because the scan does reveal metastases, sometimes employing potent combinations of hormonal therapies that have significant side effects.
However, some experts are calling for a more nuanced approach.
“We’ve encountered situations where patients have small cancerous lesions on a PSMA scan that don’t necessarily grow,” says Dr. David Einstein, Disease Group Leader of the Genitourinary Medical Oncology Program at Beth Israel Deaconess Medical Center and assistant professor at Harvard Medical School.
Comparing possible advantages to adverse effects
That it’s possible to hold off on treating PSMA-detected disease may be surprising to some busy doctors who lump such cases together with metastatic cancer. But Dr. Einstein says doctors shouldn’t lose sight of what’s already known from studying patients with biochemical recurrence.
Dr. Einstein says accelerated treatments for PSMA-detected recurrence may in some cases do little more than add years of toxic side effects to a man’s life. There’s still no evidence that treating biochemical recurrence actually improves survival, though it can delay progression and keep further PSA increases in check.
Researchers are now studying the “natural history” of prostate cancers that reappear and are detected only with PSMA scans. This means they are looking at where and when the disease tends to spread and how it behaves over time, including responding to treatment. They are also in the process of developing clinical trials for new treatments that might have longer-lasting benefits than hormonal therapies
Biochemical recurrence can be linked to a decade or more of survival when metastatic cancer that appears on conventional imaging is deemed serious and aggressive (though progression varies from person to person). This is probably true “for at least some PSMA-detected recurrences as well,” according to Dr. Einstein. In a publication published last year, Dr. Einstein and his colleagues stated that “many, if not most, men” with PSMA-detected recurrence face “no imminent threat of morbidity or mortality from their prostate cancer.”
Informed decision-making
In the meantime, Dr. Einstein says, decisions on how to handle recurring cancer spotted by PSMA scanning should take other factors into account: They include:
- A man’s age and overall health. Some older men may die of other causes before recurring prostate cancer needs treatment. Pre-existing health problems such as heart disease or frailty may also affect his tolerance to therapy.
- If a man was initially treated for high-grade cancer with aggressive features, or if the cancer has returned quickly, then earlier treatment for PSMA-recurring cancer may be warranted.
- How fast is his PSA rising? Men whose PSA levels double the fastest are at the highest risk for developing metastases in the short term and “should at least consider early treatment,” Dr. Einstein says. Those with slow PSA doubling times can wait safely and have their disease monitored instead.
- How many tumors show up on a PSMA scan? If the tumors number fewer than five, then some doctors might treat them directly with radiation, although monitoring the cancer “is also reasonable, especially in men who do not have other high-risk features,” Dr. Einstein says. Some doctors might add a temporary course of hormonal therapy (drugs that block testosterone and its tumor-promoting effects). However, Dr. Einstein cautions that it still isn’t clear that adding hormonal therapy makes radiation work better in this setting.
- A man’s personal values and goals are also important, and should be carefully considered during conversations with his doctor.
“The advanced technology of PSMA scanning that detects very small deposits of cancer has raised important treatment questions that are now being actively studied,” says Dr. Marc B. Garnick, the Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center, and editor in chief of the Harvard Medical School Guide to Prostate Diseases. “Dr. Einstein’s leadership is providing much needed guidance on how to manage prostate cancer recurrence detected by PSMA scanning,” says Dr. Garnick. “Delaying or postponing treatments that would in the past have been given immediately is a strategy that is often embraced by our patients.”
About the Author
C.W. Schmidt, Editor, Harvard Medical School Annual Report on Prostate Diseases
C.W. Schmidt is an award-winning freelance science writer based in Portland, Maine. In addition to writing for Harvard Health Publishing, he has written for Science magazine, the Journal of the National Cancer Institute, Environmental Health Perspectives, … See Full Bio
View all posts by C.W. Schmidt
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