Treatment and survival patterns of Chinese patients diagnosed with breast cancer between 2005 and 2009 in Southwest China: An observational, population-based cohort study

Abstract

Breast cancer is a significant health issue both globally and within China. Here, we present epidemiological data for female patients diagnosed with breast cancer and treated at West China Hospital, Sichuan University, between 2005 and 2009. Patients who were diagnosed with breast cancer between 2005 and 2009 were enrolled. Data cut-off in this analysis was October 2013, allowing a minimum of 3 years' follow-up, or follow-up until death. Data were collected and subject to statistical analyses to assess relationships between patient and cancer characteristics, treatment patterns and long-term outcomes. A total of 2252 women with breast cancer were included in the analyses. Luminal B was the most common subtype of breast cancer and human epidermal growth factor 2 (HER2)-positive (nonluminal) was the least common. Most patients had early-stage disease (stage ≤IIIa) at diagnosis. Patients with luminal A appeared to have the best overall survival (OS), compared with other subtypes. Hormone-receptor positivity was associated with improved prognosis, compared with negativity (OS hazard ratio [HR] 0.5). Late-stage compared with early-stage disease at diagnosis was associated with much poorer OS across all patients and tumor subtypes. Clear differences were apparent between breast cancer subtypes and the response to treatment. The interaction of breast cancer subtypes, treatments and disease stage is complex. One of the most important factors for improved prognosis is diagnosis and treatment at an early-stage of disease. With breast cancer becoming an increasingly important health concern, this highlights the importance of establishing systems and protocols to identify and treat patients with breast cancer as early as possible.

Figure 1

Survival differences for luminal B, HER2-positive, and TNBC subtypes compared with luminal A (followed up for at least 3 years). HER2 = human epidermal growth factor 2, n = number of events, N = number of patients at risk, OS = overall survival, PFS = progression-free survival, TNBC = triple negative breast cancer.

Figure 2

A, Kaplan–Meier analyses of OS and PFS for different breast cancer subtypes. B, Kaplan–Meier analyses of OS for different breast cancer subtypes by early- or late-stage disease. C, Kaplan–Meier analyses of PFS for different breast cancer subtypes by early- or late-stage disease. 95% CI = 95% confidence interval, HR = hazard ratio, HER2 = human epidermal growth factor 2, MFS = metastasis-free survival, OS = overall survival, PFS = progression-free survival, RFS = recurrence-free survival, TNBC = triple negative breast cancer.

Figure 2 (Continued)

A, Kaplan–Meier analyses of OS and PFS for different breast cancer subtypes. B, Kaplan–Meier analyses of OS for different breast cancer subtypes by early- or late-stage disease. C, Kaplan–Meier analyses of PFS for different breast cancer subtypes by early- or late-stage disease. 95% CI = 95% confidence interval, HR = hazard ratio, HER2 = human epidermal growth factor 2, MFS = metastasis-free survival, OS = overall survival, PFS = progression-free survival, RFS = recurrence-free survival, TNBC = triple negative breast cancer.

Figure 2 (Continued)

A, Kaplan–Meier analyses of OS and PFS for different breast cancer subtypes. B, Kaplan–Meier analyses of OS for different breast cancer subtypes by early- or late-stage disease. C, Kaplan–Meier analyses of PFS for different breast cancer subtypes by early- or late-stage disease. 95% CI = 95% confidence interval, HR = hazard ratio, HER2 = human epidermal growth factor 2, MFS = metastasis-free survival, OS = overall survival, PFS = progression-free survival, RFS = recurrence-free survival, TNBC = triple negative breast cancer.

Figure 3

Effect of late- vs early-stage disease at diagnosis on 3- and 5-year survival (all patients). 95% CI = 95% confidence interval, MFS = metastasis-free survival, HR = hazard ratio, OS = overall survival, PFS = progression-free survival, RFS = recurrence-free survival.

Figure 4

Multivariate analysis within tumor subgroups to show the effect of different treatment modalities on OS and PFS. 95% CI = 95% confidence interval, HR = hazard ratio, OS = overall survival, PFS = progression-free survival.