Yet another study has added to the available data on the potential of conservative management for newly diagnosed prostate cancer patients. The current study reflects experience most specifically with the management of men of ≥ 65 years of age.
The article, appearing this week in the Journal of the American Medical Association, is another restrospective analysis of data by Grace Yu-Lao and colleagues. The goal of the researchers was to evaluate the outcomes of patients with clinically localized prostate cancer managed without any immediate attempt at curative therapy in the PSA era.
Yu-Lao et al. examined data from a population-based cohort of men aged 65 years or older and diagnosed with stage T1 or T2 prostate cancer between 1992 and 2002. All patients were managed without surgery or radiation for at least 6 months after diagnosis. The patients, all of whom lived in areas covered by the Surveillance, Epidemiology, and End Results (SEER) program, were followed up for a median of 8.3 years (through December 31, 2007). Competing risk analyses were performed to assess their outcomes.
The results of the study may be summarized as follows:
- The median age of the men was 78 years at cancer diagnosis.
- 10-year prostate cancer-specific mortality was 8.3 percent for men with well-differentiated tumors; 9.1 percent for those with moderately differentiated tumors, and 25.6 percent for those with poorly differentiated tumors.
- The corresponding 10-year risks of dying of competing causes were 59.8, 57.2, and 56.5 percent, respectively.
- The 10-year disease-specific mortality for men aged 66 to 74 years diagnosed with moderately differentiated disease was 60 to 74 percent lower than in earlier studies:
- 6 percent in the contemporary PSA era (1992-2002)
- 15 to 23 percent in earlier eras (1949-1992).
- Improved survival was also observed in poorly differentiated disease.
- The use of chemotherapy (in 1.6 percent of patients) or major interventions for spinal cord compression (in 0.9 percent of patients) was uncommon.
It is hard to know exactly how to interpret some of the data in this study.
Clearly, patients with clinically localized prostate cancer diagnosed between 1992 and 2002 and given initial conservative management had notably better than outcomes than comparable patients diagnosed in the 1970s and 1980s. However, it is less clear why this should be the case. We know that PSA testing introduced what is known as stage shifting and “lead time bias.” In other words, the men were getting diagnosed earlier than they might have without the existence of the PSA test. We also know that many of these men might never have been diagnosed at all in the pre-PSA era. And many physicians believe that advances in medical care also have an impact on the prevention of death from prostate cancer.
The “New” Prostate Cancer InfoLink takes the position that the exact reason for this decline in risk for prostate cancer-specific mortality is less important than the fact that it has happened. It would seem to be apparent that we are reducing the numbers of men who have (and therefore have to be treated for) the most serious consequences of metastatic prostate cancer. We have succeeded in this because we are cognizant of their risk as opposed to ignoring it. And this appears to be the case even for those men who are managed under conservative, expectant management protocols.
It is certainly true that the average age of these men at the time of diagnosis was high (at a median of 78 years), and that conservative management might be less appropriate for selected men who have a high life expectancy and who were in the younger range of patients even in this study, but let’s not discount the good news: our ability to manage men with prostate cancer seems to be improving — even under expectant management.