This analysis examined data from all women who were diagnosed with primary breast cancer in the Auckland and Waikato District Health Board Regions between June 2000 and May 2013. Patients who received public care for primary treatment, mostly surgical treatment, were compared with those who received private care in terms of demographics, mode of presentation, disease factors, comorbidity index and treatment factors. The analysis included 14,468 patients, 8,916 (61.6%) of whom received public care. Compared to patients treated in private care facilities, patients in the public sector were older, more likely to be Māori, Pacifika or Asian and to reside in deprived neighbourhoods and rural areas. Patients in the public sector were also less likely to be diagnosed through screening, less likely to be diagnosed with early staged cancer and to receive timely cancer treatments. They were more likely to have comorbidities. They were less likely to receive breast conserving surgery with radiotherapy but more likely to have mastectomy without radiotherapy, or no primary surgery, even after adjusting for stage at diagnosis and other tumour factors. They were also less likely to receive chemotherapy and hormonal therapy. Moreover, patients in the public sector had a higher risk of mortality from breast cancer (HR 1.95; 95% CI, 1.75 to 2.17), of which 80% was explained by baseline differences, particularly related to ethnicity, stage at diagnosis and type of loco-regional therapy. After controlling for these demographic, disease and treatment factors, the risk of mortality remained 14% higher in the public sector patients.
