Abstract
Introduction: The impact of comorbidity on overall survival among older women diagnosed with breast cancer has been studied extensively. However, less is known about its impact on overall survival among women diagnosed with breast cancer before age 65 years.
Methods: We followed 4516 (1605 black, 2911 white) women ages 35 to 64 years when diagnosed with incident invasive breast cancer between 1994 and 1998. The pre-diagnosis history of 11 comorbid conditions and whether they had been treated were collected shortly after breast cancer diagnosis. Multivariate Cox regression models were used to examine the impact of these comorbidities on overall survival.
Results: During a median of 8.2 years follow-up, 1052 (524 black, 528 white) women died. The prevalence of comorbidities diagnosed before breast cancer was higher among black women than among white women (61.3% vs. 44.7%). Compared to women without any comorbidities, women were at increased risk of death if they had any treated comorbidity except when gallbladder disease; peptic, stomach, gastric, or duodenal ulcer; or liver disease was the only comorbidity. The risk of death increased with increasing number of treated comorbidities (P-trend<0.001; adjusted relative risk [RR] of death=1.21, 1.20 and 1.90 for women with 1, 2, and 3 or more comorbid conditions). However, when stratified by tumor stage, having more comorbid conditions was associated increasing mortality risk among women diagnosed with localized tumors (P-trend<0.001), but not among women diagnosed with non-localized tumors (P-trend=0.29) (P for homogeneity of trend<0.001). This risk pattern was consistent among black women and white women.
Conclusions: Among women ages 35 to 64 years when diagnosed with invasive breast cancer, having more comorbidities at breast cancer diagnosis has a greater impact on overall survival for women with localized tumors than for women with non-localized tumors.
Citation Information: Cancer Prev Res 2011;4(10 Suppl):B88.
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