Wait times and breast cancer survival: a population-based retrospective cohort study using CanIMPACT data.

Purpose: The time from breast cancer surgery to chemotherapy has been shown to affect survival outcomes; however, the effect of time from first breast cancer-related healthcare contact to first cancer specialist consultation, or the time from first breast cancer-related healthcare contact to adjuvant chemotherapy on survival has not been well explored. We aimed to determine whether various wait times along the breast cancer treatment pathway (contact-to-consultation, contact-to-chemotherapy, surgery-to-chemotherapy) were associated with overall survival in women within the Canadian province of Ontario.

Methods: We performed a population-based retrospective cohort study of women diagnosed with stage I-III breast cancer in Ontario between 2007 and 2011 who received surgery and adjuvant chemotherapy. This was the Ontario cohort of a larger, nationwide study (the Canadian Team to improve Community-Based Cancer Care along the Continuum - CanIMPACT). We used Cox-proportional hazards regression to determine the association between the contact-to-consultation, contact-to-chemotherapy, and surgery-to-chemotherapy intervals and overall survival while adjusting for cancer stage, age, comorbidity, neighborhood income, immigration status, surgery type, and method of cancer detection.

Results: Among 12,782 breast cancer patients, longer surgery-to-chemotherapy intervals (HR 1.13, 95% CI 1.03-1.18 per 30-day increase), but not the contact-to-consultation (HR 0.979, 95% CI 0.95-1.01 per 30-day increase), nor the more comprehensive contact-to-chemotherapy intervals (HR 1.00, 95% CI 0.98-1.02 per 30-day increase) were associated with decreased survival in our adjusted analyses.

Conclusion: Our findings emphasize the prognostic importance of a shorter surgery-to-chemotherapy interval, whereas the contact-to-consultation and contact-to-chemotherapy intervals have less impact on survival outcomes.