Integrating healthcare utilization databases for cancer ascertainment in a prospective cohort in a limited resource setting: the Mexican Teachers' Cohort.

PURPOSE

Prospective cohort development in low-resource settings may be limited by cancer registry population coverage; however, information routinely collected in health systems may offer opportunities to advance cancer research. We aim to illustrate in a cohort study in Mexico, a cancer ascertainment strategy that integrates multiple sources of information including healthcare utilization databases.

METHODS

The Mexican Teachers' Cohort (MTC) includes 114,545 female teachers aged 25 years and older who completed a baseline questionnaire between 2006 and 2010 and were breast cancer free. We used healthcare utilization databases (including electronic health records), self-reported breast cancer, mortality, and cancer registries to identify women with incident breast cancer. We estimated the positive predictive value for self-reported breast cancer and age-specific and age-standardized incidence rates for breast cancer and corresponding 95% confidence intervals (95%CI) calculating person-time from the date of baseline questionnaire response to diagnosis, death, or December 31, 2019.

RESULTS

Between baseline and 2019, we identified 1,313 women with incident breast cancer. We established the diagnosis in 88% using healthcare utilization databases, 6% using cancer and mortality registries, and 6% directly by contacting participants. The positive predictive value of self-reported diagnosed and treated breast cancer was 94% (95%CI 91, 97). The age-standardized incidence was 77.0 per 100,000 person-years (95%CI 75.9, 84.3). The highest incidence was observed in women aged 65-69 years (185.3 per 100,000 person-years).

CONCLUSION

Leveraging healthcare utilization databases to establish cancer diagnoses within prospective cohorts may offer an opportunity to advance global cancer research.