Kirsten Bibbins-Domingo, PhD, MD, MAS
For a man aged 55 to 69 years, the decision to be screened for prostate cancer should be an individual one, based on the man’s own values and priorities and discussions with a clinician about the potential benefits and harms of screening, the U.S. Preventive Services Task Force (USPSTF) advised in a draft recommendation.1 The draft recommendation is an update to the Task Force’s 2012 statement recommending against prostate-specific antigen (PSA)-based screening for prostate cancer regardless of age.2
The 2012 statement noted, “The benefits of PSA-based screening for prostate cancer do not outweigh the harms.” Reviewing new evidence, the Task Force now concludes “with moderate certainty that, overall, the potential benefits and harms of PSA-based screening for prostate cancer in men ages 55 to 69 are closely balanced.”1
“The Task Force is always interested in the balance, and when we looked at the science in 2012, the evidence suggested that the benefit, while present, did not outweigh the harm. Now we have shifted because of the new science that, on balance, now favors more net benefit,” Kirsten Bibbins-Domingo, PhD, MD, MAS, explained in an interview with The ASCO Post. Dr. Bibbins-Domingo chaired the USPSTF during the time that evidence was being reviewed and the draft recommendation developed and is now Immediate Past Chair. She also holds the Lee Goldman, MD, Endowed Chair in Medicine and is Professor of Medicine and of Epidemiology and Biostatistics at the University of California, San Francisco.
The USPSTF continues to recommend against PSA screening for men aged 70 and older because the potential benefits do not outweigh the expected harms, according to the draft document, which was issued for the purpose of receiving public input. The comment period closed on May 8, and the final recommendation is not expected for several months.
Balance of Benefits and Harms
“On the benefit side, we have longer follow-up from the European Randomized Study of Screening for Prostate Cancer (ERSPC) trial, which gives us more confidence about the deaths averted from prostate cancer screening,” Dr. Bibbins-Domingo said. “We also have new evidence that screening helps reduce a man’s chance of developing metastatic cancer.” The Task Force cited evidence that for every 1,000 men aged 55 to 69 offered prostate cancer screening with the PSA test, 1 to 2 men may avoid dying of prostate cancer over 10 to 15 years, and 3 men may avoid metastatic disease after 10 to 15 years.
“On the harm side, the concern of the Task Force in 2012 was overdiagnosis of tumors that were not going to cause a man a problem during his lifetime and the fact that 90% of men with a diagnosis of prostate cancer were treated with early surgery or early radiation. These treatments were considered harms, especially since most men who have surgery or radiation have incontinence or impotence as a consequence,” Dr. Bibbins-Domingo said.
“Fast forward to 2017, and we have more evidence about a strategy called active surveillance, which allows men with low-grade prostate cancer to either delay or avoid more aggressive treatment,” she continued. “This strategy appears to be effective, based on clinical trials, and we also know it is in more widespread use. Now, only 65% of men who are diagnosed actually get early surgery and radiation. So that is a shift in practice patterns.”
Not Watchful Waiting
“Active surveillance is not watchful waiting,” Dr. Bibbins-Domingo emphasized. “It is a strategy that still involves frequent blood testing and prostate biopsies. Men should be aware of the frequent monitoring that is required in order to engage in this strategy. When the cancer is found to progress, those men then may go on to surgery or radiotherapy. But it allows some men to delay surgery or radiation and some men with low-grade prostate cancer even to avoid such treatment,” she said.
“The Task Force doesn’t make recommendations about treatment approaches, and active surveillance is an approach to treatment that should be done in consultation, usually with a urologist.”— Kirsten Bibbins‑Domingo, PhD, MD, MAS
“The Task Force doesn’t make recommendations about treatment approaches, and active surveillance is an approach to treatment that should be done in consultation, usually with a urologist, who would be caring for the patient,” Dr. Bibbins-Domingo noted. “The first determination after the diagnosis of cancer is made is whether this is a low-grade cancer that is amenable to treatment with active surveillance. As is always the case, men should be informed of the benefits and risks of this approach to treatment.”
Decision Factors Change Over Time
“In understanding the balance of risks and harms, certainly factors like comorbidity, quality of life, values, and preferences might make a man choose one strategy over the other,” Dr. Bibbins-Domingo elaborated. “It is likely that these factors change over time. These decisions are not made once at age 55, with the strategy kept forever.” Rather, doctors and patients together should review and revisit these factors, she advised.
“Men should be aware that it takes on average more than 10 years to see the benefits of screening,” Dr. Bibbins-Domingo added. “If you have other health problems that might affect life expectancy or might affect your priorities in terms of your health, you might decide that given the long-time horizon to see a benefit from screening, it might not be appropriate for you.”
In addition to age, personal preferences, and values, men who have a family history of prostate cancer and those who are African American “are at higher risk of prostate cancer, and they might be factors that weigh into the decision to be screened,” Dr. Bibbins-Domingo stated. African American men are more than twice as likely as white men to die of prostate cancer.
“Based on the available evidence, the USPSTF is not able to make a separate, specific recommendation on PSA screening for prostate cancer in African American men,” according to the draft recommendation. A supporting document to help clinicians and patients make decisions about screening advises: “We encourage African American men to talk to their clinician about their increased risk of developing and dying of prostate cancer, as well as the potential benefits and harms of screening.”3
The USPSTF was also not able to make a separate, specific recommendation for men with a family history of prostate cancer. The draft recommendation statement noted:
Men who have a first-degree relative who had advanced prostate cancer at diagnosis, who developed metastatic prostate cancer, or who died of prostate cancer are probably the most likely to benefit from screening. The USPSTF believes that a reasonable approach for clinicians is to inform men with a family history of prostate cancer, particularly those with multiple first-degree relatives with prostate cancer, about their increased risk of developing cancer as well as the potential earlier age at disease onset.…
Reaching Out to Physicians and Patients
The draft document recommends that clinicians inform men aged 55 to 69 about the potential benefits and harms, and part of the plan to accomplish that is to reach out to primary care physicians. “I talked with the head of the American Urological Association, who noted that most PSA tests are still ordered by primary care physicians,” Dr. Bibbins-Domingo said. “Screening tests are done on people who don’t have signs or symptoms of disease, and those decisions are made in the primary care office.”
A research letter in JAMA Internal Medicine reported that despite Task Force recommendations, many primary care physicians and gynecologists continue to recommend breast cancer screening mammography for women who are younger and older than recommended by the guidelines.4 Asked if primary care physicians might be similarly disinclined to follow Task Force recommendations for PSA screening, Dr. Bibbins-Domingo said, “Our goal in getting the word out is not to influence rates of PSA screening, but rather to make sure that every time a PSA is ordered with the purpose of screening, there is an informed discussion.”
Complex Discussions for All
A study to determine the quality of prescreening discussions following the release of the USPSTF recommendation on prostate cancer screening found that 37% of men were told only about the advantages of PSA screening vs 30% of men who were informed about both advantages and disadvantages.5 Widespread reporting of the new draft recommendations may, however, mean more physicians will discuss the pros and cons of PSA testing with their patients.
“Let’s just acknowledge these are complex discussions—for patients and doctors. The Task Force considers it critical for men to be empowered with science and make informed decisions.… Fortunately, there are more tools now that can help guide these discussions,” Dr. Bibbins-Domingo said.
Once the prostate cancer screening recommendation is in its final form, communication strategies to disseminate the recommendation and supporting evidence will include “multiple types of media” and the involvement of prostate cancer advocacy and other groups, Dr. Bibbins-Domingo stated. “Our hope is that we will get patients who will engage and give us feedback about whether our materials make sense,” she added.
Dr. Bibbins-Domingo noted that while PSA is still “the primary way in which we screen for prostate cancers, it is really not a great test. There are many things that make PSA rise that are not cancer. Even when we do follow-up and determine that there is cancer, PSA is not that great in distinguishing low-grade cancers from more aggressive cancers. We need a better test.” ■
Disclosure: Dr. Bibbins-Domingo reported no conflicts of interest.
1. USPSTF: Draft recommendation statement: Prostate cancer screening. April 11, 2017. Available at https://screeningforprostatecancer.org. Accessed May 24, 2017.
3. USPSTF: Prostate cancer screening draft recommendations: FAQs. Available at https://screeningforprostatecancer.org/frequently-asked-questions. Accessed May 24, 2017.