Fragmentation of care in breast cancer: greater than the sum of its parts.

Introduction: Fragmentation of care (FC, the receipt of care at > 1 institution) has been shown to negatively impact cancer outcomes. Given the multimodal nature of breast cancer treatment, we sought to identify factors associated with FC and its effects on survival of breast cancer patients.

Methods: A retrospective analysis was performed of surgically treated, stage I-III breast cancer patients in the 2004-2020 National Cancer Database, excluding neoadjuvant therapy recipients. Patients were stratified into two groups: FC or non-FC care. Treatment delay was defined as definitive surgery > 60 days after diagnosis. Multivariable logistic regression was performed to identify factors predictive of FC, and survival was compared using Kaplan-Meier and multivariable Cox proportional hazards methods.

Results: Of the 531,644 patients identified, 340,297 (64.0%) received FC. After adjustment, FC (OR 1.27, 95% CI 1.25-1.29) was independently associated with treatment delay. Factors predictive of FC included Hispanic ethnicity (OR 1.04, 95% CI: 1.01-1.07), treatment at comprehensive community cancer programs (OR 1.06, 95% CI: 1.03-1.08) and integrated network cancer programs (OR 1.55, 95% CI: 1.51-1.59), AJCC stage II (OR 1.06, 95% CI 1.05-1.07) and stage III tumors (OR 1.06, 95% CI: 1.02-1.10), and HR + /HER2 + tumors (OR 1.05, 95% CI: 1.02-1.07). Treatment delay was independently associated with increased risk of mortality (HR 1.23, 95% CI 1.20-1.26), whereas FC (HR 0.87, 95% CI 0.86-0.88) showed survival benefit.

Conclusions: While treatment delay negatively impacts survival in breast cancer patients, our findings suggest FC could be a marker for multispecialty care that may mitigate some of these effects.