Comparison of self-reported initial treatment with medical records: Results from the prostate cancer outcomes study

Medical records are generally accepted as the most accurate source of information documenting cancer treatments. However, as the health care system becomes more decentralized and more cancer care is delivered in outpatient settings, it is increasingly difficult and expensive to review records from the many surgeons and medical/radiation oncologists who administer cancer therapies in the community setting. Using 1994-1995 data, the authors compared initial treatment for prostate cancer self-reported (from a mailed questionnaire or telephone/in-person interview) by 3,196 US men in the population-based Prostate Cancer Outcomes Study with information obtained from medical records. Agreement between self-reports and medical records varied by type of treatment. Generally, agreement was excellent for more invasive procedures such as prostatectomy or radiation (kappa values > 0.8), with decreasing agreement for hormone shots and pills (kappa values < 0.7). If the medical record abstract is assumed to be the "gold standard," the estimated sensitivity was generally high (>80%) for prostatectomy and radiation but low (68%) for hormone pills, although the estimated specificity was 90% or greater for all treatments. These results can serve as a useful guide to researchers contemplating the use of surveys as an alternative to medical record abstraction to ascertain treatment in studies of patient outcomes.