Comorbidities and breast cancer survival: a report from the Shanghai Breast Cancer Survival Study

Abstract

BACKGROUND We investigated the association of major comorbidities with breast cancer outcomes using the Shanghai Breast Cancer Survival Study, a population-based, prospective cohort study of Chinese women diagnosed with breast cancer. METHODS Analyses included 4,664 women diagnosed with stage I-III incident breast cancer aged 20–75 years (median age=51) during 2002–2006. Women were interviewed at 3–11 months post-diagnosis (median=6.4) and followed up by in-person interviews and linkage with the vital statistics registry. Multivariable hazard ratios (HRs) and (95% confidence intervals (CIs)) for the associations of comorbidities with breast cancer outcomes were estimated using Cox regression models. RESULTS After a median follow-up of 5.3 years (range: 0.64–8.9), 647 women died (516 from breast cancer) and 632 recurrence/metastases were documented. The main comorbidities reported included: hypertension (22.4%), chronic gastritis (14.3%), diabetes mellitus (6.2%), chronic bronchitis/asthma (5.8%), coronary heart disease (5.0%), and stroke (2.2). Diabetes was associated with increased risk of total mortality (adjusted HR: 1.40 (1.06–1.85)) and non-breast cancer mortality (adjusted HR: 2.64 (1.63–4.27)), but not breast cancer-specific mortality (adjusted HR: 0.98 (0.68–1.41)), adjusting for socio-demographics, clinical characteristics, selected lifestyle factors, and other comorbidities. Women with a history of stroke had a non-significant increased risk of total mortality (adjusted HR: 1.42 (0.91–2.22)) and a significant increased risk of non-breast cancer mortality (adjusted HR: 2.52 (1.33–4.78)), but not breast cancer-specific mortality (adjusted HR: 0.78 (0.38–1.62)). Overall, none of the comorbidities investigated were significantly associated with recurrence. CONCLUSIONS In this large prospective cohort of breast cancer survivors, diabetes was significantly associated with increased risk of total and non-breast cancer mortality, and history of stroke was associated was associated with increased risk of non-breast cancer mortality.

Cardiovascular risk in middle-aged breast cancer survivors: a comparison between two risk models

“…Similarly, other studies have reported diabetes mellitus in 6.2 28 , 8 11 and 9% 14 of BCS. In the SBCS study, diabetes was associated with a 40% higher risk of total mortality and death unrelated to breast cancer, but not breast cancer-specific mortality 28 .…”

“…Similarly, other studies have reported diabetes mellitus in 6.2 28 , 8 11 and 9% 14 of BCS. In the SBCS study, diabetes was associated with a 40% higher risk of total mortality and death unrelated to breast cancer, but not breast cancer-specific mortality 28 . In another study of BCS, diabetes was associated with a 39% increased risk of all-cause mortality, similar to rates observed in diabetics without breast cancer 30 .…”

“…Other studies reported hypertension in 26 14 and 50.6% 27 of BCS. In the Shanghai Breast Cancer Survival (SBCS) study, hypertension was the most common comorbid condition, affecting 22.4% of the participants 28 . In the Life after Cancer Epidemiology (LACE) study, hypertension was independently associated with an increased risk of all-cause mortality, due to causes both related and unrelated to breast cancer 29 .…”

Diabetes and Other Comorbidities in Breast Cancer Survival by Race/Ethnicity: The California Breast Cancer Survivorship Consortium (CBCSC)

“…Breast cancer patients with a history of cardio-vascular disease experienced elevated overall mortality in two cancer registry-based studies (1, 16) and elevated breast cancer-specific mortality in another study (20), but not in two smaller, non-cancer registry-based studies (18, 19). As noted above, the omission of radiotherapy may have adverse effects on recurrence rates and overall mortality (28–30).…”

“…Both cancer registry-based (1, 3, 14–17) and non-registry based (18, 19) studies reported higher risk of overall mortality in diabetic breast cancer patients. Few studies have investigated the effects of diabetes on breast cancer-specific mortality; increased mortality was reported in two studies (18, 20), but not in a third study which also adjusted for BMI and other lifestyle factors (19). Our results strengthen the evidence that diabetes is associated with breast cancer-specific mortality.…”