A comparison of outcomes of different eras of conservative treatment for localized prostate cancer indicates that overall and prostate cancer-specific survival rates are higher for men diagnosed from 1992 through 2002 compared to men diagnosed in the 1970s and 1980s, according to a study in the September 16 issue of JAMA.
“Among men, prostate cancer is the most common nonskin cancer and the second most common cause of cancer death in the United States. When diagnosed, prostate cancer is contained within the prostate in approximately 85 percent of cases, and standard treatment options usually include surgery, radiation, or conservative management (active surveillance or deferral of treatment until necessitated by disease signs or symptoms),” according to background information in the article. “Despite its potential as a reasonable treatment choice, however, conservative management has been used in only about 10 percent of patients, perhaps because of a limited understanding of and contemporary data on the anticipated course and outcomes of this approach.” The authors add that this lack of reliable contemporary information makes it difficult for patients and their physicians to anticipate outcomes and make informed treatment decisions.
Grace L. Lu-Yao, M.P.H., Ph.D., of the Cancer Institute of New Jersey and UMDNJ-Robert Wood Johnson Medical School, Piscataway, N.J., and colleagues analyzed data for men with localized T1 or T2 prostate cancer to evaluate the outcomes of conservatively managed localized prostate cancer diagnosed in the contemporary prostate-specific antigen (PSA) era. The population-based cohort study included 14,516 men age 65 years or older when they were diagnosed (1992-2002) with stage T1 or T2 prostate cancer and whose cases were managed without surgery or radiation for 6 months after diagnosis. Living in areas covered by the Surveillance, Epidemiology, and End Results (SEER) program, the men were followed up for a median (midpoint) of 8.3 years (through December 2007). The median age at diagnosis was 78 years.
The researchers found that ten-year prostate cancer–specific mortality was 8.3 percent for men with well-differentiated tumors, 9.1 percent for moderately differentiated, and 25.6 percent for those with poorly differentiated tumors. The corresponding 10-year risks of dying of causes other than prostate cancer were 59.8 percent, 57.2 percent, and 56.5 percent for each respective group.
Ten-year disease-specific mortality for men age 66 to 74 years diagnosed with moderately differentiated disease was 60 percent to 74 percent lower than earlier studies. “Survival results in our contemporary PSA era study cohort were more favorable than results previously reported. For example, in the current study, 10-year prostate cancer–specific mortality was 6 percent in the contemporary PSA era (1992-2002) compared with results of previous studies (15 percent-23 percent) in earlier eras (1949-1992) for men aged 65 to 74 years diagnosed with moderately differentiated disease. Improvement in survival among men with older age or poorly differentiated disease was also observed,” the authors write.
“The substantial improvement in survival that we observed in our study compared with previous reports might be explained, in part, by additional lead time, overdiagnosis related to PSA testing, or grade migration, among other factors. Prostate-specific antigen testing identifies disease 6 to 13 years before it presents clinically. Contemporary patients identified through such testing would be expected to live at least 6 to 13 years longer because of this lead time. In addition, previously documented systematic upgrading of modern tumors compared with earlier eras makes more recently graded tumors appear to have a more benign course, resulting in longer survivals. Finally, it is also possible that advancements in medical care might have led to improved outcomes.”
“The net overall effect is that outcomes following conservative management are now significantly better than those reported in previous eras; therefore, physicians and their patients may need to reconsider this management option, particularly in light of randomized trial data from the pre-PSA era suggesting little if any benefit to more aggressive intervention.”