Cancer
Estimating breast cancer recurrence in a population-based registry in Georgia, US Chrystelle Kiang* Chrystelle Kiang Micah Streiff Rebecca Nash Deirdre Cronin-Fenton Anke Huels Kevin C. Ward Timothy L. Lash
Although the descriptive epidemiology of primary breast cancer is well characterized in the US, breast cancer recurrence rates have not been measured at the population level. The number of breast cancer survivors is growing, so a clearer understanding of the descriptive epidemiology of recurrence is a pressing need.
We estimated recurrence rates in the Cancer Recurrence and Information Surveillance Program cohort in the Georgia Cancer Registry. We included 25,103 female patients with stage I-III breast cancer diagnosed between 2013 to 2017 who completed primary treatment and had no evidence of disease at least one year after diagnosis, with follow up through 2019. We used missing date methods to impute the outcome of breast cancer recurrence based on an internal validation substudy and further informed by combinations of certain records in the registry (e.g., pathology reports, imaging claims), prognostic variables (e.g., stage), and missing data indicators (e.g., insurance coverage). We pooled HRs across 1000 imputed datasets, adjusted for age, stage, grade, subtype, race and ethnicity, marital status, and urban/rural county at diagnosis.
There were 1,610 patients with a validated outcome (75% with breast cancer recurrence) and we imputed the outcome for the remaining 23,493 patients. The overall incidence of recurrence was ~10% for up to 5 years of follow up. The hazard of recurrence increased as stage and grade increased, but there was no notable difference by tumor subtype. Compared to those aged 55–64 at diagnosis, the HR (95% CI) for ages 35–44 was 1.17 (0.73, 1.87) and 1.05 (0.71, 1.53) for ages 45–54. Compared to Non-Hispanic (NH) White patients, the HR (95% CI) for Hispanic patients was 1.55 (0.89, 2.69), 1.32 (0.56, 3.12) for NH Asian and Pacific Islander patients, and 0.94 (0.73, 1.22) for NH Black patients.
For the first time, we report on the descriptive epidemiology of breast cancer recurrence for up to 5 years in a population-based registry.