Retrospective Study Identifies Mortality Predictors in Southern Ethiopian Breast Cancer Cohort

Women treated for breast cancer at two hospitals in southern Ethiopia had an estimated three-year overall survival of 23.9% in a retrospective cohort study of 492 patients, with 152 deaths recorded during maximum follow-up of 36 months. Advanced-stage disease, moderate or poor Nottingham Prognostic Index scores, a higher neutrophil-to-lymphocyte ratio, and the absence of hormonal therapy were independently associated with a higher hazard of death from any cause in the study’s multivariable analysis. The researchers described the findings as regional evidence on survival and prognosis, rather than proof that any single factor caused the outcomes.

Breast cancer remains the most frequently diagnosed malignancy among women worldwide and a leading cause of cancer-related mortality. The article reports that approximately 2.3 million women were diagnosed with breast cancer globally in 2022 and that about 666,000 deaths were attributed to the disease. Survival outcomes vary markedly across health systems, with the paper noting that five-year survival exceeds 90% in many high-income countries but is substantially lower in many low- and middle-income settings.

The study authors linked these differences to factors such as limited screening, delayed diagnosis, inadequate diagnostic capacity, and restricted access to surgery, radiotherapy, and other appropriate treatment. Ethiopia faces a growing breast cancer burden alongside limited and unevenly distributed cancer services. The source reports national incidence and mortality estimates of approximately 40.8 and 24.0 per 100,000 women, respectively, and notes that breast cancer represents about one-third of cancers diagnosed among women in the Addis Ababa Cancer Registry.

Despite the availability of curative and palliative services at the two hospitals studied, access to essential components of breast cancer care remained constrained. The evidence from southern Ethiopia is particularly useful because previous Ethiopian survival studies have largely focused on Addis Ababa and the country’s northern and western regions. The investigation used medical records from Hawassa University Comprehensive Specialized Hospital and Wolaita Sodo University Comprehensive Specialized Hospital.

Eligible participants were women aged 18 or older with confirmed breast cancer diagnosed between January 1, 2020, and December 31, 2022. Investigators used a systematic random sampling procedure to select 507 records, of which 492 met the inclusion criteria and entered the analysis. Follow-up began at confirmed diagnosis and continued until death, loss to follow-up, discharge with medical advice, the last documented contact, or the administrative end of observation, whichever occurred first.

Data came from medical files, electronic databases, operative notes, and other clinical documentation, with telephone contact used when vital status was uncertain. The analytical cohort had a median age of 40 years and an interquartile range of 34 to 49 years. Women aged 35 to 50 accounted for 267 of 492 participants, or 54.27%, while 290, or 58.94%, lived in rural areas and 138, or 28.05%, had never attended school.

Disease presentation was often advanced: 314 women, or 63.82%, had stage III or IV disease, 253, or 51.42%, had distant metastasis, and 241, or 48.98%, had positive axillary lymph nodes. Ductal carcinoma accounted for 390 diagnoses, or 79.27%. The Nottingham Prognostic Index, a measure combining tumor size, lymph-node stage, and histological grade, placed 225 women, or 45.70%, in the poor-prognosis category.

During follow-up, 152 women, or 30.9% with a 95% confidence interval of 26.8% to 35.0%, died from any cause; 283, or 57.5% with a 95% confidence interval of 53.1% to 61.8%, were alive at the end of observation; and 57, or 11.6% with a 95% confidence interval of 8.8% to 14.5%, were lost to follow-up. The cohort accumulated 5,634.9 person-months at risk, and median survival was 28.1 months, with a 95% confidence interval of 23.2 to 30.8 months. Kaplan–Meier estimates were 71.8% at one year, 54.5% at two years, and 23.9% at three years.

The observed death rate was 3.1 per 100 person-months for early-stage disease and 3.7 per 100 person-months for advanced disease. The Nottingham Prognostic Index showed a wider gradient in the Kaplan–Meier estimates. Death rates were 0.5 per 100 person-months among women with an excellent score, 2.5 per 100 person-months among those with a moderate score, and 5.6 per 100 person-months among those with a poor score.

In the adjusted Cox proportional hazards model, advanced-stage disease was associated with a 1.73-fold higher hazard of death compared with early-stage disease, with a 95% confidence interval of 1.19 to 2.51. Relative to an excellent Nottingham Prognostic Index score, a moderate score was associated with a 1.20 adjusted hazard ratio, with a 95% confidence interval of 1.01 to 4.20, while a poor score was associated with a 2.30 adjusted hazard ratio, with a 95% confidence interval of 1.50 to 5.10. Two additional factors were associated with survival after adjustment for other measured variables.

This ratio was calculated from pretreatment blood counts by dividing the absolute neutrophil count by the absolute lymphocyte count. The study notes that an elevated ratio can reflect systemic inflammation and an imbalance between neutrophil-mediated tumor progression and lymphocyte-mediated antitumor responses. Women who received hormonal therapy also had a lower hazard of death than those who did not, with an adjusted hazard ratio of 0.64 and a 95% confidence interval of 0.44 to 0.92.

These associations should not be interpreted as causal effects. Hormone-receptor and HER2 results were available for only 243 of the 492 participants, preventing subtype-specific multivariable analyses. The authors cautioned that the hormonal-therapy association may reflect the underlying effectiveness of endocrine therapy among receptor-positive tumors, but differences in unmeasured clinical characteristics, treatment access, and selection into therapy could also have influenced the estimate.

The neutrophil-to-lymphocyte ratio and Nottingham Prognostic Index are readily obtainable from routine clinical information, but their prognostic performance has not been established as a clinical test in this cohort. Age, residence, menopausal status, education, surgical-margin status, histological type, surgery, chemotherapy, and diagnosis-to-treatment interval were not significantly associated with survival after adjustment because their confidence intervals included one. Several measurements documented gaps in the treatment pathway.

Chemotherapy was administered to 417 women, or 84.76%, but 332 of those receiving it, or 79.62%, received less than 80% of their prescribed cycles and were classified as nonadherent. Only 22 women, or 4.47%, received radiotherapy. The interval from histopathological confirmation to initiation of definitive treatment was less than one month for 210 women, or 42.68%, and at least one month for 282, or 57.32%.

The findings identify interruptions across diagnosis and treatment, although the retrospective observational design cannot determine how much each service gap contributed to survival. The study has important limitations. It covered only two hospitals, relied on routinely recorded information, and excluded patients with missing baseline clinical characteristics, unknown outcomes, unavailable telephone responses, and lost charts.

Excluding incomplete records could have introduced selection bias if the excluded women differed from those analyzed. Some deaths outside healthcare facilities may not have been captured, while loss to follow-up and censoring could affect the survival estimates. The retrospective design also limits causal interpretation, and the use of the same underlying cohort in an earlier analysis of neutrophil-to-lymphocyte ratio means the present results are not a new prospective cohort.

Nevertheless, the study provides a detailed regional description of survival, disease stage, treatment delivery, and accessible prognostic indicators in an area for which longitudinal evidence remains limited.

Subject of Research: Clinical predictors of mortality and overall survival among women with breast cancer in southern Ethiopia

Article Title: Survival Status and Predictors of Mortality Among Women With Breast Cancer in Southern Ethiopia: A Retrospective Cohort Study

Article References: Desta, B., Chema, T. Z., Sisay, S., Nigusie, M., & Balta, B. (2026). Survival Status and Predictors of Mortality Among Women With Breast Cancer in Southern Ethiopia: A Retrospective Cohort Study. Cancer Reports, 9(10), Article e70722. https://doi.org/10.1002/cnr2.70722

Image Credits: AI Generated

DOI: 10.1002/cnr2.70722

Keywords: breast cancer, Ethiopia, retrospective cohort, overall survival, mortality predictors, Nottingham Prognostic Index, neutrophil-to-lymphocyte ratio, hormonal therapy, cancer staging, treatment access, Survival, Status