Population-based assessment of emergency room visits and hospitalizations among women receiving adjuvant chemotherapy for early breast cancer.

Purpose: Adjuvant chemotherapy is considered standard care for patients with lymph node (LN) -positive and high-risk LN-negative early breast cancer (EBC). Although chemotherapy-associated toxicities are documented in clinical trials, the impact of toxicities on emergency room (ER) visits and hospitalizations (ER + Hs) at a population level with contemporary chemotherapy is unknown. We undertook a population-based study of ER + Hs in patients with EBC receiving adjuvant chemotherapy compared with noncancer controls (NCCs).

Methods: All patients diagnosed with EBC between January 2007 and December 2009 in Ontario, Canada, were identified from the Ontario Cancer Registry. Patient records were linked deterministically to provincial health care databases to provide comprehensive medical follow-up. All patients received ≥ one cycle of adjuvant chemotherapy. Patient cases of EBC (n = 8,359) were matched to NCCs (n = 8,359) on age, comorbidity, and geographic location. ER + Hs within 30 days of chemotherapy were identified. If the primary reason for the visit was a common chemotherapy toxicity, the visit was considered chemotherapy associated. All-cause and chemotherapy-associated visits were compared between patient cases and controls. Logistic regression models were used to identify covariates associated with ER + Hs.

Results: The proportion of patients with at least one ER + H was significantly higher in patients with EBC undergoing chemotherapy compared with NCCs (43.4% v 9.4%; P < .001). Patients with EBC were also more likely to have multiple ER + Hs (17.9% v 2.4%; P < .001). On multivariable analysis, comorbidity, receiving a regimen containing docetaxel, and certain geographic regions were associated with increased odds of ER + Hs.

Conclusion: ER + Hs are common among patients with EBC receiving chemotherapy and significantly higher than among controls. This represents a potential opportunity for quality improvement.