Multimorbidity and overall survival among women with breast cancer: results from the South African Breast Cancer and HIV Outcomes Study

Abstract

Background Breast cancer survival in South Africa is low, but when diagnosed with breast cancer, many women in South Africa also have other chronic conditions. We investigated the impact of multimorbidity (≥ 2 other chronic conditions) on overall survival among women with breast cancer in South Africa. Methods Between 1 July 2015 and 31 December 2019, we enrolled women newly diagnosed with breast cancer at six public hospitals participating in the South African Breast Cancer and HIV Outcomes (SABCHO) Study. We examined seven chronic conditions (obesity, hypertension, diabetes, HIV, cerebrovascular diseases (CVD), asthma/chronic obstructive pulmonary disease, and tuberculosis), and we compared socio-demographic, clinical, and treatment factors between patients with and without each condition, and with and without multimorbidity. We investigated the association of multimorbidity with overall survival using multivariable Cox proportional hazard models. Results Of 3,261 women included in the analysis, 45% had multimorbidity; obesity (53%), hypertension (41%), HIV (22%), and diabetes (13%) were the most common individual conditions. Women with multimorbidity had poorer overall survival at 3 years than women without multimorbidity in both the full cohort (60.8% vs. 64.3%, p = 0.036) and stage groups: stages I–II, 80.7% vs. 86.3% (p = 0.005), and stage III, 53.0% vs. 59.4% (p = 0.024). In an adjusted model, women with diabetes (hazard ratio (HR) = 1.20, 95% confidence interval (CI) = 1.03–1.41), CVD (HR = 1.43, 95% CI = 1.17–1.76), HIV (HR = 1.21, 95% CI = 1.06–1.38), obesity + HIV (HR = 1.24 95% CI = 1.04–1.48), and multimorbidity (HR = 1.26, 95% CI = 1.13–1.40) had poorer overall survival than women without these conditions. Conclusions Irrespective of the stage, multimorbidity at breast cancer diagnosis was an important prognostic factor for survival in our SABCHO cohort. The high prevalence of multimorbidity in our cohort calls for more comprehensive care to improve outcomes for South African women with breast cancer.

The South African breast cancer and HIV outcomes study: Profiling the cancer centres and cohort characteristics, diagnostic pathways, and treatment approaches

“…Major findings were that the cohort had a high burden of HIV and common noncommunicable diseases, which results in frailty, necessitating less aggressive treatment approaches [ 27 , 28 ], poorer responses to neoadjuvant chemotherapy and negatively impacts overall survival [ 17 , 21 , 27 ]. The sites differed in age and ethnicity distributions of patients managed and had differing pathways for patients to access diagnostic and cancer treatment centres.…”

“…Each participating hospital had dedicated study interviewers who collected sociodemographic characteristics, risk factors, comorbidities, and breast cancer clinical information knowledge and awareness of breast cancer and delay periods to diagnosis as previously described [ 6 , 17 ]. Some of the collected information and variables included the following: sociodemographic information (such as age, marital status, employment status, and level of education completed); behavioural factors (alcohol consumption, smoking); reproductive history (use of oral and injectable contraceptives, number of full-term pregnancies).…”

“…Mortality rates for cancer are not routinely reported by the SA pathology-based SANCR and this motivated us to establish the South African Breast Cancer and HIV Outcomes cohort (SABCHO) study [ 6 ] at 5 tertiary cancer centers located in two Provinces of South Africa (Gauteng and KwaZulu-Natal). Summary findings include that the cohort bares a high HIV and noncommunicable diseases multimorbidity (MM) burden [ 17 ] and that 58% of the cohort is diagnosed with late-stage (III and IV) disease [ 18 ] and delays in initiating surgical treatments, chemotherapy, radiotherapy, and endocrine therapy occurred, particularly for women living less than 20 kilometres from the hospital or not speaking English [ 12 ]. At 3-years post diagnosis, the overall mortality rate was a high 47% for women with stage I-III breast cancer and 80.5% for women with stage IV disease, compared with just 10% in the United States (US) [ 19 , 20 ].…”

“…At 3-years post diagnosis, the overall mortality rate was a high 47% for women with stage I-III breast cancer and 80.5% for women with stage IV disease, compared with just 10% in the United States (US) [ 19 , 20 ]. We showed that stage at diagnosis, HIV, multimorbidity and delays to initiating surgery as the first treatment all negatively impact overall survival [ 17 , 20 – 22 ].…”

Correction: Multimorbidity and overall survival among women with breast cancer: results from the South African Breast Cancer and HIV Outcomes Study

“…Following publication of the original article [ 1 ], the authors reported an error in the title. There is a break in the title and a large blank space besides the “background” section.…”