Validation of Identifying Cancer Diagnosis Based on Self-Reported Information in the Japan Nurses' Health Study

Area of Science:

• Epidemiology
• Oncology
• Public Health

Background:

• The Japan Nurses' Health Study (JNHS) is a large-scale, nationwide prospective cohort study involving female nurses.
• This study focused on validating self-reported cancer diagnoses within the JNHS cohort (N=15,019).

Purpose of the Study:

• To assess the accuracy of self-reported cancer diagnoses (stomach, colorectal, liver, lung, thyroid) in the JNHS.
• To evaluate the reliability of the JNHS Validation Study Committee's decisions using physician-reported data as a gold standard.

Main Methods:

• Compared self-reported diagnoses with committee decisions and physician-reported data.
• Calculated positive predictive values (PPVs) to determine diagnostic validity.
• Utilized biennial follow-up surveys, additional outcome surveys, and medical facility surveys.

Main Results:

• Initial self-reports had varying PPVs (e.g., 77.8% stomach, 41.7% liver).
• Additional outcome surveys significantly improved PPVs (e.g., 96.2% stomach, 82.5% lung).
• Committee decisions showed high PPVs (e.g., 100% stomach, 94.7% lung), with low reliance on death certificates for most cancers.

Conclusions:

• Self-reported cancer diagnoses in the JNHS are generally valid for stomach, colorectal, lung, and thyroid cancers.
• Enhanced validation methods improve the accuracy of cancer ascertainment in large cohort studies.
• The findings support the utility of self-reported data in cancer epidemiology research.