Research study investigates survival rates of prostate cancer patients across time periods

New research to be published in tomorrow's issue of the Journal of the American Medical Association (JAMA) (Vol. 302, No. 11), by a team at The Cancer Institute of New Jersey (CINJ), shows that men diagnosed with prostate cancer beginning in the early 1990's had significantly improved survival outcomes compared with patients whose cancers were diagnosed in prior decades. The time period studied is an era when methods of diagnosing, classifying and treating prostate cancer all underwent significant changes. The investigators say their finding may prompt a reassessment of treatment options for localized prostate cancer. CINJ is a Center of Excellence of UMDNJ-Robert Wood Johnson Medical School.

The study, Outcomes of Localized Prostate Cancer Following Conservative Management, examined 14,516 men aged 66 or older who were diagnosed with prostate cancer from 1992 through 2002 and did not receive surgery or radiation within six months of diagnosis. The researchers utilized information from the Surveillance, Epidemiology and End Results (SEER) cancer registries and healthcare encounter data collected by Medicare. All of the SEER registries hold the highest level of certification of data quality.

The study found that the risk of dying from prostate cancer over a ten-year period following diagnosis declined by more than 60 percent compared with patients diagnosed in the 1970s and 1980s. For example, among patients with intermediate-risk cancer, men aged 66 to 74 had between a two and six percent chance of dying from prostate cancer within ten years compared to 15 to 23 percent in the earlier period. The authors say the improvement in survival rates since the early 1990's could relate to such factors as earlier diagnosis due to the increased use of a blood test called the prostate specific antigen (PSA) test, changes in how disease is classified, and advances in medical care. The improved survival reported in JAMA is in line with findings of another study to be published tomorrow by some of the same authors in the Journal of the National Cancer Institute (JNCI) (Volume 101, Issue 18), which documents significant changes in the contemporary risk profile of prostate cancer patients.

The JAMA research also showed that men aged 66 and older with low- to intermediate-risk cancer without initial surgery or radiation have a low risk of needing palliative therapy. Only four to eleven percent of men in this group used palliative surgery, radiation, or chemotherapy to alleviate pain or cancer symptoms over a ten-year period following diagnosis. It also was determined that between 56 and 60 percent of men in the study (depending on tumor grade) had a risk of dying of causes other than prostate cancer within ten years following diagnosis.

Grace Lu-Yao, PhD, MPH, cancer epidemiologist at CINJ and associate professor of medicine at UMDNJ-Robert Wood Johnson Medical School and of epidemiology at UMDNJ-School of Public Health, is the lead author of the JAMA study and the senior author of the JNCI study. She notes that the survival outlook for prostate cancer, especially disease detected through the PSA test, has not been well described and that the study by her team represents the most comprehensive look at this subject to date. "The lack of solid data has often made it difficult for medical professionals to determine the most appropriate treatment and to predict patient outcomes for this population. These latest findings depict a more accurate survival outcome for the contemporary prostate patient," she noted.

One unique feature of the JAMA research, according to Dr. Lu-Yao, is that more than half of the study subjects were over age 78. While older men (age 75 and older) are the prime candidates for conservative management, data specific to this age group is sparse because this group has often been excluded or under-represented in other studies, according to the authors.

Lu-Yao cautions that because the men in the study were older than 65, the data may not apply to younger patients. She also notes that longer follow-up data are needed for prostate patients who are expected to live for more than ten years.