Down-staging and improving survival of breast cancer in SA – Dr Herbert Cubasch
Dr Herbert Cubasch
- Dept of Surgery and Batho Pele Breast Clinic Division, University of Witwatersrand, Wits Health Consortium of University Witwatersrand and Chris Hani Baragwanath Academic Hospital
Title of the project
Down-staging and improving survival of breast cancer in South Africa.
The overall purpose of this project is to identify the major drivers of breast cancer stage (early or late) at diagnosis and of survival that can be targeted in South African disadvantaged communities to save lives.
In South Africa, breast cancer (BC) is the most common cancer in women, outnumbering cervix uterus. Although incidence rates (number of newly diagnosed cases per year) are half of those in Western countries (age-standardized rate of 41.0 in SA vs 89.1 in the UK per 100,000 women), death rates are as high as in high-incidence countries (20.7 in SA vs 18.7 in the UK. Incidence rates are expected to increase markedly owing to westernization of lifestyles, changing fertility patterns (less an dlater pregnancies) and increasing cancer risk factor profiles (e.g. obesity and physical inactivity). BC is an excellent-prognosis cancer if diagnosed at an early stage, thus down-staging (earlier stage of BC at patient presentation) is an imperative to improving survival rates from this disease.
In late 2006, the PI initiated standardized clinical data collection and electronic entry, of all patients diagnosed with invasive BC at the Chris Hani Baragwanath Academic Hospital breast clinic. This detailed case data now form the largest well-documented breast cancer case series for tthe continent of Africa, upon which we wish to build a more extensive epidemiology research programme. The initial analyses of the data, reported in 3 accredited publications (2-4) since award of the CANSA grant, have revealed important findings for the South African breast cancer setting, which are summarized below:
- In the absence of mammography screening, a strong trend of earlier presentation occurred over 6 years, from 70% to 48% at late stages III and IV, demonstrating that urgently-needed down-staging to earlier stages at BC presentation of women at public healthcare clinics is realistically achievable in this and similar settings. Of 1000 women diagnosed with BC this improvement would result in an additional 80 women alive 5 years after diagnosis. We have also established that patients who lived >20km from CHBAH were more likely to be diagnosed at stage III or IV than patients who lived <20km distant. However, the balance of the factors, both at the woman-level (education, awareness, use of healthcare services) and at the health-service level (access to healthcare, referral processes and household socioeconomic status) need to be precisely investigated. Optimization of this encouraging down-staging trend can then be applied in other similar settings. To date we are not aware of any detailed survival studies of determinants of survival from BC in African women populations.
- The large case series (which stands at >1,700 as of May 2014) demonstrates that the predominant breast estrogen-receptor positive tumors (which are generally less aggressive). Contrary to previous reports that BC in AFrican women is excessively aggressive and has an early onset, this large case series demonstrates that the majority of the breast cancer clinical burden is not different to that in women in the Northern Hemisphere, and thus that it has the potential to also benefit from early diagnosis (as they are slower growin tumors) and from a good prognosis. Saying this, the smaller proportion (20%) of triple negative (aggressive) breast tumors also need to be studied in terms of their survival. Determinants of survival will be examined, namely clinical and woman-level and health-service level factors.
- Additionally, Soweto is an HIV-endemic area. Though our own baseline results confirm findings in western populations that HIV status does not have an effect on breast cancer risk or on major prognostic indicators at diagnosis, future studies on the implications of HIV on survival need to be initiated and this is the perfect setting in which to do this. Of particular interest is whether lack of compliance to breast cancer treatments is more common in HIV+ women (e.g. owing to decreased tolerance to toxic chemotherapy) and how this impacts on survival.