br From the Department of Urology University of
From the Department of Urology, University of Pittsburgh, Pittsburgh, PA; the Divi-sion of General Internal Medicine, University of Pittsburgh, Pittsburgh, PA; the Depart-ment of Medicine, Center for Research on Health Care, University of Pittsburgh, Pittsburgh, PA; the Dartmouth Institute for Health Policy and Clinical Practice, Lebanon, NH; the Dartmouth Institute Geisel School of Medicine, Lebanon, NH; and the Depart-ment of Health Policy Management, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA
Address correspondence to: Bruce L. Jacobs, M.D., M.P.H., Department of Urol-ogy, University of Pittsburgh, 5200 Centre Avenue, Suite 209, Pittsburgh, PA 15232. E-mail: [email protected]
ARTICLE IN PRESS
Although the side effects associated with these treat-ments are well described and routinely evaluated with dis-ease-specific assessments of functional status, the extent to which each treatment affects a patient’s general functional status (eg, physical and emotional well-being) is under-studied. The assessment of general functional status is broadly applicable across multiple types of conditions, but as a result, pertains more frequently to geriatricians and general practitioners rather than specialists who 3X FLAG Peptide treat pros-tate cancer.5,6 Nonetheless, understanding how prostate cancer treatment affects general functional status is impor-tant for several reasons. First, knowing how various treat-ments affect general functional status can help inform patients deciding among several reasonable treatments.7 Second, patients with low functional status may benefit from further evaluation and/or intervention to help improve their condition.8 Third, clinicians are increasingly recognizing the value of patient-reported outcome meas-ures, such as functional status, in characterizing a patient’s overall outcome after treatment.9
For these reasons, we sought to examine the relation-ship between treatment and subsequent functional status among older men with localized prostate cancer. Specifi-cally, we assessed the association of prostate cancer treat-ment (conservative management, surgery, radiation) with subsequent physical function (as measured by activities of daily living [ADLs] and physical component summary [PCS] scores) and emotional well-being (as measured by mental component summary [MCS] scores).
Data Source and Study Population
Using the Surveillance, Epidemiology, and End Results-Medicare Health Outcomes Survey (SEER-MHOS) data, we identified men aged 65 years or older diagnosed with localized prostate cancer between 1998 and 2009, with follow-up data available through 2010. SEER is a nationally representative cancer registry that comprises approximately 26% of the United States’ population;10 MHOS is a survey that includes patient-reported functional status for a subsample of Medicare Advantage beneficiaries.11 The response rate is 63% for baseline surveys and 79% for follow-up surveys.12
We identified men with localized prostate cancer as their first and only cancer who completed 2 surveys: one within 2 years prior to treatment and one within a year after treatment. We chose to limit the cohort to those with a survey within 1 year after treat-ment because health-related quality of life tends to mirror that of controls after that period.13 We categorized patients based on their treatment within 1 year after diagnosis. In addition, we included noncancer patients who completed 2 surveys. Using these criteria, we identified 40,177 noncancer patients, 143 conservative man-agement patients, 59 surgery patients, and 206 radiation patients.
Outcome: Functional Status
The outcomes included three measurements of functional status within 2 domains: 1) physical function (ADL and PCS scores) and 2) emotional well-being (MCS scores). We chose ADLs as our primary outcome since we felt specialists treating prostate cancer were most familiar with this measurement. We weighted ADL scores using a validated weighted scheme developed by
Finch and colleagues using magnitude estimation to convert functional status to a continuous scale.14 This approach assigns greater weight to loss of ADLs associated with greater disability (eg, loss of toileting has a higher weight than loss of ability to dress). We then normalized the weighted ADL disability score to a 100-point scale for ease of interpretation, where indicates independence and 100 indicates functional dependence.15
The PCS and MCS scores were secondary outcomes. The PCS and MCS scores are calculated from the Short Form 36 (SF-36) and the Veterans RAND 12-item health survey (VR-12) ques-tionnaires. The SEER-MHOS database contains responses from the SF-36 from 1998 through 2005 and from the VR-12 from 2006 through the end of the study period.11 The PCS and MCS scores are either calculated directly from the VR-12 or are rescored as the VR-12 equivalent of the SF-36 scores. The scores are nor-malized to the general population with a mean of 50 and a stan-dard deviation of 10.16 Higher scores indicate better function.