A man’s life expectancy should serve as the basis for determining, on a case-by-case basis, whether prostate-specific antigen screening is appropriate, according to a new provisional clinical opinion issued by the American Society of Clinical Oncology.
Specifically, for men who are not expected to live longer than 10 years, ASCO agrees with the May 2012 guideline from the U.S. Preventive Services Task Force (USPSTF) that the risks brought on by PSA screening outweigh the benefits (Ann. Intern Med. 2012 May 22 [epub ahead of print]).
For men with a longer life expectancy, however, "it is recommended that physicians discuss with their patients whether PSA testing for prostate cancer screening is appropriate for them. PSA testing may save lives but is associated with harms, including complications from unnecessary biopsy, surgery, or radiation treatment," ASCO panel cochair Dr. Ethan Basch and his associates wrote (J. Clin. Oncol. 2012 July 16 [doi:10.1200/JCO.2012.43.3441]).
The ASCO panel also recommended that information written in lay language be available to clinicians and their patients to facilitate the discussion of the benefits and harms associated with PSA testing before the routine ordering of a PSA test. A "decision aid," based on the ASCO provisional clinical opinion (PCO), was to be made available at www.asco.org/pco/psa.
Calculation of life expectancy is based on multiple individual factors and circumstances. The PCO mentions one available life expectancy calculator as an example, but the ASCO panel does not endorse any one calculator over another.
ASCO Differs on PSAs for Younger Men
In an interview, Dr. Basch said that the ASCO panel evaluated essentially the same data as did the USPSTF. This included screening studies and treatment studies in which men who screened positive for cancer based on PSA testing were randomly assigned to either prostate surgery or watchful waiting. The multidisciplinary ASCO panel, which includes individuals with clinical expertise in medical oncology, urology, radiation oncology, and statistics, paid particular attention to subgroup analyses and statistical issues, however.
"For older men or those with shorter life expectancy, our current recommendations are the same as [those of] the USPSTF. For younger men there is a divergence, in an area where research results are complex and the balance between risks and benefits is close.
"Ultimately, it was the judgment of the ASCO panel that the balance between risks and harms for younger men depends on individual values and preferences, and therefore must be evaluated on a case-by-case basis by a patient and his physician, and must be well informed by scientifically accurate decision tools," said Dr. Basch, a medical oncologist specializing in prostate cancer at Memorial Sloan-Kettering Cancer Center, New York.
USPSTF Official Sees Similarities
Although urologists denounced the USPSTF recommendations at the annual meeting of the American Urological Association, and delegates to the American Medical Association did likewise at their meeting, ASCO agrees more than it disagrees with the controversial guideline, according to Dr. Michael L. LeFevre, co–vice chair of the task force.
"I’m struck by the similarities between the recommendations more than the differences," he said in an interview.
"ASCO concluded that the benefits don’t outweigh the harms, and even with [fewer than] 10 years’ life expectancy, the benefits might not outweigh the harms. ... We certainly also say that that assessment doesn’t mean that an individual clinician cannot offer screening, nor that an individual man can’t request screening,"
"The similarity between the two guidelines is that anybody doing PSA screening should be doing it as an informed choice," added Dr. LeFevre, the Future of Family Medicine professor and vice chair of the department of family and community medicine at the University of Missouri, Columbia.
The USPSTF tries to update its recommendations every 5 years, but may update earlier if important studies are published, as happened in this case. Two major studies are not yet published, Dr. Lefevre noted: PIVOT (Prostate Cancer Intervention Vs. Observation Trial) probably won’t prompt an update, but the PROTECT study "is large enough that I’m really hoping it will inform some of the unanswered questions that we have today."
Two Trials Key to ASCO Opinion
A "provisional clinical opinion" (PCO) is ASCO’s evidence-based approach to offering rapid responses to emerging data in clinical oncology. It is intended "to offer timely clinical direction to ASCO members after publication or presentation of potentially practice-changing data from major studies." In this case, the authors used the Agency for Health Research and Quality’s (AHRQ’s) review, which was also the basis for the USPSTF’s review.
Of the five randomized controlled trials identified, the ASCO panel deemed only two to be of sufficient quality. The PLCO (Prostate, Lung, Colorectal, and Ovarian Cancer) screening trial, involving 76,685 men aged 55-74 years, showed no statistically significant differences in overall or prostate cancer–specific mortality at 7 years between men who were offered annual PSA screens and those who received usual care. However, half of the "usual care" group also received PSA screenings (J. Natl. Cancer Inst. 2012;104:125-32).