Prostate cancer is a leading cause of death by cancer for men in developed countries and cases are increasing globally. It’s also a malady whose cure can be worse than the disease. Common screening methods can’t discriminate between cancer and benign diseases, let alone identify life-threatening tumors. A diagnosis exposes patients to harmful treatments for an often slow-moving illness that doesn’t necessarily threaten life or health; researchers estimate that a third of men treated for prostate cancer were never going to die from it. Many were subjected to potentially dangerous exams and procedures that made them impotent or incontinent. New tests on the horizon promise safer, more precise diagnoses. The challenge will be to validate and utilize the new tools before growing skepticism born of overtreatment discourages early detection and threatens to reverse a two-decade slide in prostate cancer mortality.
Researchers from Brisbane to Brussels are developing MRI imaging techniques intended to more accurately evaluate prostate cancer risk, especially the likelihood of aggressive tumors. The scans are also expected to make it easier for urologists to determine whether a biopsy is needed and pinpoint where. Urologists are increasingly turning to a newer, safer approach via the perineum that avoids puncturing the rectum and causing potentially lethal infections. What’s more, researchers are developing PET scanning techniques that help identify cancer cells that have spread from the prostate to the bone and nearby tissues, enabling earlier, more precise treatment for secondary tumors, or metastatic disease.
The risk of developing prostate cancer increases with age, which is one reason there’s less of it in poorer countries where people don’t live as long. In rich countries like Australia, one in five men will be diagnosed with the disease before their 85th birthday. Worldwide, that’s about 1.1 million cases a year, making it the most common malignancy for men after lung cancer. In 1975, two-thirds of men in the U.S. were dead within five years of their prostate-cancer diagnosis. Today, the five-year survival rate is almost 100 percent, and 94 percent of men are still alive after 15 years, thanks to better treatments and early detection. A blood test for prostate-specific antigen, or PSA, led to a huge jump in diagnosed cases during the 1980s and early 1990s. Until recently, PSA was part of routine physical examinations for men over 50. The test fell out of favor because it’s led to overtreatment. Doctors have to screen and treat early at least 1,000 men to prevent one prostate-cancer death. But in the process, 30 to 40 men will develop erectile dysfunction or urinary incontinence because of surgery, medications and radiotherapy. In the past five years, a new hurdle has emerged: multidrug-resistant bacteria. A prostate biopsy typically entails sending a needle about a dozen times through the wall of the rectum to collect specimens from the walnut-sized gland. The test is risky because the needle can infect the prostate, bladder and bloodstream with bowel-dwelling bacteria. It’s potentially deadly when the bacteria are resistant to antibiotics.
In 2012, the U.S. Preventive Services Task Force recommended against PSA-based screening for prostate cancer, saying the potential harm outweighed its limited benefits. On the other hand, groups such as the American Urological Association and American Cancer Society say PSA screening may be useful in early detection, especially for men with a family history of the disease and those in their 50s and 60s who understand the risks. At the center of the debate are the inaccuracies and risks associated with the current diagnostic process — an elevated PSA level leading to transrectal prostate biopsy — and men being harmed by treatments they don’t need. New diagnostic tools that promise greater accuracy and safety could soon end the prostate cancer conundrum — so long as men and their doctors aren’t deterred by bad experiences of the past.
The Reference Shelf
- The U.S. Preventive Services Task Force released its final recommendations on prostate cancer screening in May 2012, prompting responses from groups including the American Cancer Society and the American Urological Association.
- Simon Chapman, professor of public health at the University of Sydney, and colleagues wrote a book about prostate cancer testing in 2010, and Peter Scardino, head of surgery at New York’s Memorial Sloan Kettering Hospital, wrote a guide to treatment the same year. Last year, he was co-author of a paper overviewing innovations in prostate cancer detection and management.
- The Prostate Cancer Foundation aggregates information on research efforts from around the world.
- Atul Gawande wrote about overdiagnosis and overtreatment in the May 11, 2015, issue of The New Yorker.
First published May 13, 2015
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