Previous research by the study’s lead author Grace Lu-Yao, PhD, MPH, cancer epidemiologist at the Cancer Institute of New Jersey and professor of medicine at Rutgers Robert Wood Johnson Medical School, and colleagues examined 10-year outcomes for this population (JAMA, Vol. 302, No. 11). The 2009 research showed men diagnosed with prostate cancer beginning in the early 1990’s had significantly improved survival compared with patients whose cancers were diagnosed in prior decades. Given the protracted nature of the disease and increasing longevity among elderly men, 10-year follow-up may not be sufficient to make informed treatment decisions. Dr. Lu-Yao notes this new study, which extends data examination by an additional five years, “helps provide a more complete picture of potential outcomes for patients who have a life expectancy greater than 10 years.”
The new research, which appears in the current online edition of European Urology (doi: 10.1016/j.eururo.2015.03.021), examined 33,137 Medicare patients aged 65 or older who were diagnosed with early-stage (T1 or T2) prostate cancer from 1992 through 2009 and received conservative management (no surgery, radiotherapy, cryotherapy or androgen deprivation therapy) within the first six months of diagnosis. The researchers utilized information from the Surveillance, Epidemiology and End Results (SEER) cancer registries and Medicare claims. All SEER registries hold the highest level of certification of data quality.
Investigators found that men aged 64 to 74 with a Gleason score (a grading system that indicates how likely a tumor will spread) of between five and seven had a lower risk (5.7 percent) of dying from prostate cancer over a 15-year period as compared to men 75 and older, whose risk was 10.1 percent. For men with the highest level Gleason scores (between eight and 10), 15-year prostate cancer mortality rates were 22 percent for men aged 65 to 74 and 27 percent for men 75 and older.
The authors also note mortality rates remained relatively stable from six to 16 years following diagnosis. The work also examined if these men had comorbid diseases and found that those who did have other health problems had a lower risk of dying from prostate cancer due to deaths from competing health issues.
“The proportion of men diagnosed with localized prostate cancer who choose to have conservative management is relatively small but, is on the rise. The information provided by this long-term study will help facilitate treatment decisions,” says Lu-Yao. “Our study, which includes data from the PSA testing era, is a more current representation of outlook survival for this population.”
Lu-Yao indicates the study could help change the conversation between patient and physician. “In weighing whether treatment benefits outweigh the risks, radical prostatectomy — for instance — is typically not recommended for older men with low-grade disease. But many elderly patients are treated with radiotherapy or hormonal therapy even if their cancer is indolent, so that they can feel like they are doing something,” she says. “By having additional data available to support conservative management, doctors can further educate their patients about survival outcomes and possibly help avoid treatments that may put the patient at risk.”
The authors note strengths of the study include the fact it is population based and broadly representative instead of focused on specific geographic areas or institutions. Lu-Yao also notes the study provided information on more than 10,000 men aged 75 or older — a population which is often omitted from studies. But they also caution that because the men in the study were older than 65, the data may not apply to younger patients.