Prostate Cancer Research

UMMC Urologist’s Research Uses Metabolomics to Hunt for Aggressive Prostate Cancers

With 1 in 5 American men over age 35 choosing to undergo a vasectomy, this popular birth control method has always provoked strong feelings. But new research from a prominent University of Maryland Medical Center (UMMC) urologist has perhaps made vasectomy even more controversial, indicating the procedure may increase the risk of aggressive or lethal prostate cancer.

In a study of 51,000 men published in the July 2014 issue of the Journal of Clinical Oncology, Mohummad Minhaj Siddiqui, M.D., director of urologic robotic surgery, found a 20% relative risk increase of high-grade prostate cancers in men with vasectomies compared to those without. But he cautions that while prostate cancer is common — affecting about 1 in 6 men in his lifetime — dying from the disease is not, and the elevated risk due to vasectomy translates to only an additional 3 in 1,000 men diagnosed.

Dr. Siddiqui completed the research while a urology resident at Harvard before joining the University of Maryland School of Medicine faculty.

“It definitely did provoke a big response,” he says of the paper. “If you’d asked me when I started the project, I would have said my hunch is there is no relationship. A lot of patients, when they hear the context of the risk, say it’s not so bad. But it is helpful to know that’s the potential risk someone may be encountering.”

Advanced Imaging Focused on Metabolomics

Dr. Siddiqui, also an assistant professor of surgery-urology at University of Maryland School of Medicine, has made prostate cancer research a huge focus of his career. With the two standard prostate cancer treatments — surgery and radiation — leading to significant risks of urinary incontinence and erectile dysfunction, Dr. Siddiqui wants to expand the number and accuracy of techniques to reliably distinguish between aggressive tumors and the low-grade, nonlethal cancers affecting most patients.

“What adds to the challenge of the disease is you have to treat people who will be harmed by it, but also figure out who won’t be harmed and not over-treat them,” he explains. “It’s a disease where there’s really a lot to do.”

Some of his research concentrates on identifying the metabolic traits of prostate cancer, part of a burgeoning field known as metabolomics. Aggressive prostate cancer cells have a higher metabolism — in essence, working harder than other cells — and imaging this metabolism can pinpoint more concerning tumors. UMMC recently acquired a cutting-edge hyperpolarized carbon-13 imaging system that offers this capability, becoming one of only five centers in the country with the technology.

“You almost want to miss the nonaggressive cancers so the patient doesn’t have to deal with the thought of having cancer,” he says. “We don’t want to cause a lot of anxiety in men who don’t have aggressive cancer and don’t need to know about it.”

Optimizing Surveillance for Affected Men

Advanced MRI is also emerging as an optimal tool for this purpose because it won’t “see” less aggressive cancers, so anything showing up on images is more likely to be a dangerous malignancy. Dr. Siddiqui is collaborating with UMMC radiologists to incorporate MRIs into standard care, expanding on the use of only prostate-specific antigen (PSA) blood tests that detect both low- and high-grade tumors.

Once prostate cancer has been diagnosed, some men opt for “watchful waiting” — regular surveillance that often requires periodic biopsies to determine if the cancer is progressing. “The goal, instead of repeat biopsies, is to do repeat MRIs,” he says. “It’s less invasive and more comfortable.”

Dr. Siddiqui is also beginning the process of forming a clinical trial to study focal brachytherapy, which places radioactive seeds into cancerous sections of the prostate instead of the entire gland, as in standard brachytherapy.

With about 30,000 American men dying of prostate cancer each year, he’s aware of the impact his chosen career emphasis may have on the disease.

“It’s not a minor issue,” he says. “Just as we’re not great about trying to avoid treatment, we’re also not great at optimizing treatment for men with really aggressive disease. That’s on the horizon.”

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