A discussion of prostate cancer and the elderly is a microcosm of the overall debate regarding the screening, detection, and treatment of localized prostate cancer for all men, irrespective of age. Drs. Ko and Bubley are correct, however, in pointing out that elderly patients present unique challenges given the indolent natural history of the cancer, the high incidence of clinically insignificant tumor, and the presence of comorbid disease that competitively causes symptoms or death. Their excellent review nicely captures some of the complexity of the debate, although I believe there are three questions that remain to be answered.
Is It Appropriate to Check Men Over Age 75 for Prostate Cancer?
An important distinction here is the difference between cancer screening and cancer detection. While most men diagnosed with prostate cancer are more than 65 years of age, many of these men were evaluated because of urinary symptoms (ie, retention, hematuria, or incontinence) or systemic symptoms from metastatic disease (ie, weight loss, bone pain, or azotemia). Early diagnosis and treatment is clearly indicated for men who have symptomatic or advanced prostate cancer, since treatment can alleviate symptoms and potentially prolong life.
In contrast, the importance of prostate cancer detection in the asymptomatic elderly patient is unknown. It is still unproven that population-based prostate cancer screening significantly decreases morbidity and mortality.[1] Prostate cancer has a prolonged natural history, and more men will die with prostate cancer than from prostate cancer. Prostate cancer can take 10 to 20 years to run its course, and it often occurs in older men with other, more immediate threats to longevity.
While almost 65% of 70-year-old men harbor microscopic foci of prostate cancer on autopsy, there is only a 20% lifetime probability that a clinically apparent tumor will occur.[2] Applying cancer screening programs to older men has the potential for detecting many of these biologically indolent tumors (pseudodisease), subsequently increasing health-care costs and morbidity caused by pseudodisease and side effects from treatment, yet doing nothing to improve overall quantity or quality of life.[3] Although the scientific evidence to date suggests that PSA-based screening programs do not detect these clinically insignificant tumors, the broad application of screening to the elderly will probably result in the treatment of some men who otherwise would never develop symptoms or die from prostate cancer.
So, should we be checking asymptomatic men over the age of 75 for prostate cancer? At this time, there is some evidence that screening and treatment in asymptomatic men who have more than a 10-year life expectancy can reduce cause-specific mortality.[4] In addition, improvements in the treatment of both localized and advanced disease mean fewer side effects and better preservation of quality of life, which makes treatment more acceptable to the elderly male.[5] Finally, average life span itself represents a moving target, with progressive increases expected to occur into the middle of the next century.[6] Strict cutoffs based on age should not be used, since average life span does not predict a specific individual’s risk of dying. A screening decision based on an individualized, quantitative estimate of life expectancy seems more reasonable.[7]
Since there is no strong scientific evidence that shows a benefit for prostate cancer screening, the best suggestion at this time is to offer PSA testing on an individual basis—based on a conceptual framework that reviews the individual patient’s comorbidity, life expectancy, family history, fear of disability from cancer, and cognitive state.[7,8] Because of time constraints, a specific discussion of the risks and benefits of screening can be difficult in the primary care setting, but there are many helpful brochures for patient education such as those produced by the American Foundation for Urologic Disease or the American Academy of Family Practice.[9,10]
A 70-year-old man with a history of localized prostate cancer treated with whole-pelvis radiation therapy with a boost to the prostate, in conjunction with androgen deprivation therapy 7 years prior, presented with lower back pain. A bone scan revealed an area of activity in the sacrum. What is the most likely diagnosis?
