While no resource is perfect, it is worthwhile to familiarize yourself with some contemporary methodology and predictive tools to help determine life expectancy in localized prostate cancer patients.
Ariel Schulman, MDThere is an old surgical adage that “the best surgeon knows when not to operate.” While much of early residency is focused on how to operate, there is an expectation that more senior trainees become more familiar with non-surgical strategies for indolent disease or patients with significant competing morbidities. This is particularly relevant for men with localized prostate cancer where the patient’s functional state and life expectancy must be integrated into screening, diagnostic, and management decisions.
While no resource is perfect, it is worthwhile to familiarize yourself with some contemporary methodology and predictive tools to integrate into clinical practice. Sammon et al published a well-done study in European Urology (2015; 68:756-65) in 2015 that is worth reviewing.
Age is the best predictor of life expectancy. According to the Social Security Administration (SSA) Actuarial Life Tables from 2013, life expectancy for newborn males and females in the United States is 76.28 and 81.05 years, respectively. And the longer one lives, the longer the overall life expectancy becomes so that the average 60-year-old man has a life expectancy of 81.48 years.
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In addition to age, comorbid conditions and functional limitations must be integrated. Validated indices including the Charlson comorbidity index and more recently the Elixhauser comorbidity index offer objective tools to quantify comorbidities. But it should be noted that neither was designed or validated to predict 20- to 30-year longevity. The Eastern Cooperative Oncology Group (ECOG) Performance Status and Karnofsky Performance Status are widely used functional classifiers, particularly in the medical oncology community, to guide prognosis and treatment strategies.
In recent years, there has been significant interest in the surgical community to better integrate objective tools to quantify perioperative risks. The American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) risk calculator and Physiological and Operative Severity Score for enUmeration of Mortality and Morbidity (POSSUM) incorporate multiple clinical variables to predict complications and mortality after surgery. While these scores identify high-risk surgical patients, they were not designed to guide the other required management decisions.
The current National Comprehensive Cancer Network Guidelines for Prostate Cancer Version 2.2017 endorse “the clinician’s assessment of overall health” to supplement the SSA tables. Men deemed to be in the best quartile of health have a 50% greater life expectancy, while life expectancy is reduced by 50% for men considered to be in the worst quartile. Men in the second and third quartile would have the life expectancy assigned by the tables. It is worth noting that the uniformly accepted American Society of Anesthesiologists (ASA) score for patients undergoing surgery similarly relies on a subjective assessment of overall health.
Consider a 60-year-old man as an example. Actuarial tables predict an additional 21.48 years of life expectancy. Those determined to be in the best quartile of health would have 50% more years (21.48+10.74=32.22 years) and would be expected to live to age 92.22, while those in the worst quartile of health would have a 50% reduction (21.48–10.74=10.74 years) and would be expected to live to 70.74 years. Thus, 60-year-old men in the lowest projected quartile have a 10- to 11-year life expectancy, the middle two quartiles have a 21- to 22-year life expectancy, and the highest quartile has a 32 year life expectancy.
Interestingly, calculators from large insurance companies incorporate a range of additional factors not considered during most physician visits. An online lifespan calculator from Northwestern Mutual incorporates compliance with medical care, stress, diet and exercise, and driving history. In this model, binge drinking or a driving while intoxicated conviction in the past 5 years reduces life expectancy by 5-10 years. Divorce has also shown to have a detrimental impact on male survival in longevity studies. Thus, as we know intuitively, what is listed in the medical chart doesn’t always tell the whole story.
Like many tools, risk calculators offer additional objective data to improve decision-making, but are used optimally when incorporated with other available information. In the end, the clinician’s “good judgment” is required to put together all of the pieces and offer reasonable options to each patient. Ultimately, being familiar with one or two scoring systems to use when treating more complex patients and to justify management in the medical record will likely be to your benefit.
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