Prostate Cancer Screening: New Data Support Watchful Waiting
Tumor aggressiveness may not change over time, authors say (August 14)
Prostate cancer aggressiveness may be established when the tumor is formed and might not be altered with time, according to a study published in Cancer Research, a journal of the American Association for Cancer Research (AACR).
Investigators found that after the introduction of widespread prostate-specific antigen (PSA) screening, the proportion of patients diagnosed with advanced-stage cancers dropped by more than six-fold in 22 years, but the proportion diagnosed with high Gleason-grade cancers did not change substantially. This suggests that low-grade prostate cancers do not progress to higher grade over time, the authors said.
“Cancer stage” refers to the extent or spread of the disease, and “cancer grade” — called the Gleason grade for prostate cancer — refers to the aggressiveness of the disease.
The new study adds more evidence to the argument that patients who are diagnosed with low-grade prostate cancers can opt for an active-surveillance, or “watch-and-wait,” approach instead of getting treated right away.
Kathryn Penney, ScD, of the Harvard Medical School, and her colleagues used data from 420 participants recruited to the Physicians’ Health Study and from 787 participants recruited to the ongoing Health Professionals Follow-up Study. All of the participants were diagnosed with prostate cancer between 1982 and 2004, and were treated with surgery. The researchers re-analyzed prostate tissue collected from these patients to assess the Gleason grade.
They found that the number of participants who had undergone PSA screening increased from 42 percent in 1994 to 81 percent in 2000.
They also found that the number of late-stage cancers decreased from 19.9 percent in the 1982–1993 group to 3.0 percent in the 2000–2004 group, reflecting an 85 percent drop in stage at diagnosis. However, there was only a moderate decrease in high Gleason-grade cancers, from 25.3 percent in the 1982–1993 group to 17.6 percent in the 2000–2004 group, reflecting a 30 percent drop.
“Radical prostatectomy or radiation therapy, the usual treatments for prostate cancer, can have negative side effects, such as impotence and incontinence; choosing active surveillance could prevent this decline in quality of life,” said Penney. “Men with low-grade disease at diagnosis should seriously consider talking with their doctors about active surveillance.”
Source: AACR; August 14, 2013.