A study published in the Journal of the National Cancer Institute reveals that there is no difference in mortality rates between men participating in the Prostate, Lung, Colorectal and Ovarian Cancer (PLCO) Screening Trial, and men who receive usual care after 13 years follow-up.
In November 1993, the multi-center, two-arm, PLCO Trial, began enrollment with follow-up, through December 2009. The trial assessed the effect of screening on prostate, lung, colorectal, and ovarian cancer. Participants had no previous history of these cancers and were aged between 55 and 74 years of age. Men in the control group received their usual care, which for some participants included screening. For 6 years, men in the intervention group, underwent yearly PSA testing as well as yearly digital rectal examination for 4 years.
Gerald. L. Andriole, M.D., of Washington University School of Medicine in St. Louis, and his team analyzed outcomes of the participants through 13 years, as a previous report of PLCO results was criticized that the follow-up period was too short.
The team discovered no difference in mortality between the intervention group and the control group, although they found a statistically considerable 12% relative increase of high-grade prostate cancer among participants in the intervention group than those in the control group. Furthermore, the researchers found no apparent differential effect of screening by co-morbidity, age category or pre-trial PSA testing.
The researchers explain:
"Improvements in prostate cancer treatment are probably at least in part responsible for declining prostate cancer mortality rates. Even if life is only prolonged by therapy, the opportunities for competing causes of death increase, especially among older men."
In addition, the researchers highlight that 455 (10.7%) of the 4,250 prostate cancer case patients diagnosed in the intervention group died of other causes, while 377 (9.9%) of the 3,815 men diagnosed with prostate cancer in the control group also died of other causes.
The researchers say:
"Thus, a higher percentage of deaths from other causes rather than a deficit occurred among the prostate cancer patients diagnosed in the intervention arm, an indication of the over-diagnosis associated with PSA detection."
After follow-up data through 15 years becomes available, the team plan to update the mortality findings from prostate component of the PLCO again.
Written by Grace Rattue