A few more studies reported in the news, thanks to the conference in Orlando, Florida. If you want to read about another that just is so infuriatingly UNhelpful than the totally confusing baldness study, (NEIrish has full head of hair, but with a "monk-like" thinness barely visible) here's one on a PSA study:
ORLANDO -- An initial PSA value <3 ng/mL predicted a low risk of prostate cancer and a remote likelihood that a man would die of the disease, results of a large screening study showed.
Fewer than 6% of men developed prostate cancer over an 11-year period following a first-time screening PSA value lower than 3 ng/mL. Subsequently, 23 men died of the disease, resulting in a mortality of 0.15%, Dutch investigators reported in a study that will be presented here at the Genitourinary Cancers Symposium later this week.
The median time to diagnosis of prostate cancer in men with the lowest initial PSA values exceeded eight years, said Monique Roobol, MD, of Erasmus University Medical Center in Rotterdam.
The low cancer risk and prolonged interval to diagnosis have potentially major implications for use of PSA to screen for prostate cancer.
"These results provide justification for a PSA threshold of ≥3 ng/mL for prostate biopsy," Roobol said during a press briefing.
"The results can also contribute to individual risk stratification and management of men in PSA-based screening programs," she said. "For example, the favorable outcomes in men with initial PSA values of less than 1 ng/mL -- who accounted for 45% of men between the ages of 55 and 74 -- supports prolongation of the screening interval up to, for example, eight years."
Las Vegas urologic oncologist Nicholas Vogelzang, MD, agreed that the Dutch study drives another nail into the coffin of annual PSA screening for low-risk men.
"I believe that this study gives us some confidence that annual PSA screening is going to soon become a thing of the past," said Vogelzang, of Comprehensive Cancer Centers of Nevada, who moderated the briefing.
"A low PSA, particularly men with a PSA less than 1, and probably those with a PSA less than 2, could be considered for substantially longer intervals of PSA screening. We formerly learned that a PSA of four was the threshold for a prostate biopsy. This study suggests the number should drop to 3."
Use of PSA to screen for prostate cancer has a controversial history. Since the test became widely available in the 1990s, disease stage at diagnosis has migrated to the lowest, most curable stages.
Supporters of screening with PSA point to the near-100% five-year survival except for the cancers associated with distant metastasis as evidence that screening with PSA works.
PSA's detractors argue that the test merely uncovers clinically insignificant cancers that would not have posed a mortality threat if they had never been discovered. Diagnosis of prostate cancer at early stages has led to significant overtreatment, morbidity and cost, they argue.
A key issue in the controversy relates to the most appropriate PSA value for identifying men with an increased risk of prostate cancer. The European Randomized Study of Screening for Prostate (ERSPC) used a PSA value of 3.0 ng/mL as the cutoff for a prostate biopsy.
Roobol reported findings from an analysis of a Dutch cohort included in ERSPC. The cohort comprised 42,376 men ages 55 to 74 and living in the Rotterdam area. The researchers randomized 19,950 of the participants to serial screening PSA tests, and men who had initial PSA values ≥3 ng/mL underwent prostate biopsy.
Roobol and her co-investigators focused on the 15,758 (79%) men who had PSA values <3.0 ng/mL at their first screening test. Follow-up screening occurred at four-year intervals.
From 1993 through 2008, 915 (5.8%) of the 15,758 men had prostate cancer diagnoses and 23 (0.15%) died during a median follow-up of 11 years.
The investigators determined 182 of the cancers were detected between screenings, and 169 (1.1%) had characteristics associated with more aggressive cancer (clinical stage >T2c, Gleason score >8, PSA at diagnosis >20 ng/mL, and spread to lymph nodes or distant sites).
Within the range of PSA values from undetectable to 3 ng/mL, prostate cancer incidence and mortality increased.
Of the 7,126 men with PSA values <1 ng/mL, 129 (1.8%) eventually had prostate cancer diagnoses, and three (0.04%) of the men died of prostate cancer.
Of the 6,156 men with PSA values of 1.0 to 1.9 ng/mL, 415 developed (6.7%) prostate cancer, and 11 (0.18%) died of the cancer.
The remaining 2,476 men had PSA values of 2.0 to 2.9 ng/mL; 371 (15.7%) of them developed prostate cancer and nine (0.36%) died of the disease.
As compared with men who had initial PSA values <1.0 ng/mL, men with first-time values of 1.0 to 1.9 ng/mL had a significantly higher incidence (HR 4.0, P<0.001), proportion of aggressive cancers (HR 2.7, P<0.001), and prostate cancer mortality (HR 3.9, P=0.038).
Corresponding hazards for men in the PSA range of 2.0 to 2.9 ng/mL were HR 10.3 for incidence (P<0.001), HR 6.9 for aggressive cancers (P<0.001) and HR 7.5 for prostate cancer mortality (P=0.003).