Using Life Expectancy, Not Age, to Make Cancer Screening Decisions Can Maximize Potential Benefits

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Using life expectancy, rather than chronologic age, to inform decisions about whether to continue cancer screening for older persons can maximize the potential benefits of screening, while minimizing the harms, according to results of a population-based cohort study of 407,749 people over 66 without a history of cancer. 

“Persons with higher levels of comorbidity had shorter life expectancies, whereas those with no comorbid conditions, including the very elderly, had favorable life expectancies relative to an average person of the same chronological age,” Hyunsoon Cho, PhD, of the National Cancer Institute, and colleagues reported in the Annals of Internal Medicine. “Comorbidity-adjusted life expectancy may help physicians tailor recommendations for stopping or continuing cancer screening for individual patients,” the researchers concluded.

Patients without a history of cancer were identified from a random 5% sample of Medicare beneficiaries residing in Surveillance, Epidemiology, and End Results (SEER) cancer registry areas. More than 30% of the cohort members had one or more comorbid conditions. Information was not available on functional status and severity of comorbidity, “which might influence life expectancy in elderly persons,” the investigators cautioned. 

The researchers used a three-step approach to estimate life expectancy by comorbidity. The first step included estimating the effect of comorbid conditions on survival and constructing a comorbidity score, using this score to classify comorbidity status as no, low/medium, or high comorbidity. 

The second step involved estimating age-specific survival curves for each of those comorbidity status groups and the three most common comorbid conditions—diabetes, chronic obstructive pulmonary disease, and congestive heart failure. The final step was to estimate comorbidity-adjusted life expectancy.

Death Hazards

“Of all comorbid conditions examined, AIDS was associated with the highest risk for death [hazard ratio = 3.66, 95% confidence interval (CI) = 2.72–4.92]. Persons with diabetes, [chronic obstructive pulmonary disease], and [congestive heart failure] had, respectively, at least a 1.45, 1.76, and 2.27 times greater hazard of dying compared with those with no comorbidity. The hazard of death for persons in the high comorbidity group was at least 1.76 times greater than that of persons in the no-comorbidity group,” the researchers reported.

“Relative to the life expectancy of the average U.S. population, the estimated life expectancy for persons aged 75 years with no comorbidity was approximately 3 years longer, but for persons with high comorbidity, it was approximately 3 years shorter. As age increases, the effect of comorbidity on life expectancy decreases,” the investigators added.

The authors concluded that their study findings and methods “may aid physicians and other health practitioners in individualizing recommendations for cancer screening in elderly persons (that is, to continue screening in persons with sufficient life expectancy who might benefit or to stop screening among those for whom benefits are unlikely). Even with additional information about life expectancy,” the authors added, “discussions about continuing or stopping screening are complex and will need to be informed by patient preferences.” ■

Cho H, et al: Ann Intern Med 159:667-676, 2013.