Minimum data set.

Background
Breast cancer (BC) is the leading cause of cancer-related morbidity and mortality in women living in South Africa, a country with a high HIV burden. However, characteristics of the double burden of HIV and BC in South Africa have not been properly investigated. We described characteristics of BC cases by HIV status in South Africa.
Methods
In this nationwide South African study, we obtained BC records for women aged ≥15 years diagnosed in the public health sector between January 2004 and December 2014. We included records from the National Cancer Registry that had been linked to HIV-related laboratory records from the National Health Laboratory Service. We assessed the odds of being HIV positive versus HIV negative in relation to patient-, cancer-, and municipality-related characteristics.
Results
From 2004–2014, 40 520 BC cases were diagnosed in women aged ≥15 years. Of these, 73.5% had unknown HIV status, 18.7% were HIV negative, and 7.7% were HIV positive. The median age at BC diagnosis was 43 years (interquartile range [IQR]: 37–52) in HIV positive and 57 years (IQR: 46–68) in HIV negative women, respectively. The odds of being HIV positive was higher for women who were aged 30–34 years compared to women aged 35–39 years at cancer diagnosis (odds ratio [OR] 1.38, 95% confidence interval [CI] 1.10–1.71), Black versus non-Black (OR 6.41, 95% CI 5.68–7.23), diagnosed with cancer in rural versus urban areas (OR 1.59, 95% CI 1.40–1.82) and diagnosed in municipalities with low and middle (OR 3.46, 95% CI 2.48–4.82) versus high socioeconomic position (OR 2.69, 95% CI 2.11–3.42).
Conclusion
HIV status was unknown for the majority of BC patients. Among those with known HIV status, being HIV positive was associated with a younger age at cancer diagnosis, being Black and receiving care in municipalities of poor socioeconomic position. Future studies should examine opportunities to integrate HIV and BC control programs.