New Tool Weighs Cancer Screening Strategy, Life Expectancy

Larry Hand

November 18, 2013

Physicians may be better able to tailor cancer screening recommendations for elderly patients by using a new tool that estimates comorbidity-adjusted life expectancy, according to an article published online November 18 in the Annals of Internal Medicine.

Even when using the tool, however, physicians still need to consider patient preferences when making such complex decisions, write Hyunsoon Cho, PhD, from the National Cancer Institute, Bethesda, Maryland, and colleagues.

The investigators analyzed Medicare data on 407,749 elderly persons to develop tables that can be used to estimate life expectancies for patients who have or do not have comorbid conditions.

The researchers found that persons with more comorbidities had shorter life expectancies and when compared with an average person the same age, whereas persons with no comorbid conditions had life expectancies beyond the average.

For example, the researchers estimate that a 75-year-old healthy person has a life expectancy of 3 years longer compared with the average US population. In contrast, a person with multiple conditions has a life expectancy of 3 years shorter than average individuals who are the same age.

However, as age increases the effect of comorbidities on life expectancy decrease. For example, compared with an average white male, a white man with multiple conditions could live 6 years less at age 66 years but only 1 year less at age 90 years.

The study population included Medicare beneficiaries who were alive and at least 66 years old during the period 1992 and 2005 and included mostly women (60.7%) and whites (85.9%). The researchers excluded beneficiaries who had previously had a cancer diagnosis.

Diabetes, chronic obstructive pulmonary disease (COPD), and congestive heart failure (CHF) were the most common comorbidities in the study population, although AIDS accounted for the highest risk for death (hazard ratio [HR], 3.66; 95% confidence interval [CI], 2.72 - 4.92). The researchers calculated hazard ratios for CHF at 2.27, COPD at 1.76, and diabetes at 1.45.

3-Step Approach

To arrive at their estimates, the researchers first estimated effects of comorbidities on survival and scored individuals according to no comorbidity, low/medium comorbidity, or high comorbidity. They then estimated age-specific survival curves for the 3 most common conditions (diabetes, COPD, and CHF). Finally, they estimated comorbidity-adjusted life expectancy on the basis of those findings.

The study population my not be representative of the entire US population, which may limit the generalizability of the results. Another limitation of the study was that data on functional status and severity of conditions were not available.

The researchers note that they found considerable variation in life expectancy, which means cancer screening decisions should be tailored to individual patients.

"Life expectancy rather than chronological age could be used to inform cancer screening guidelines to ensure that patients live long enough to benefit from early detection," they write. "The comorbidity-adjusted life expectancy developed here may facilitate clinical decision-making and recommendations tailored to individual patients. For example, some men and women at a younger chronological age with high levels of comorbidity might not benefit from cancer screening."

This research was supported by the National Cancer Institute and the Centers for Disease Control and Prevention. The authors have disclosed no relevant financial relationships.

Ann Intern Med. Published online November 18, 2013.


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