Background: Epidemiologic studies suggest that type 2 diabetes increases breast cancer risk and goes along with an increased mortality, however, there has been limited experimental evidence supporting this evidence. The purpose of this study was to evaluate the clinical outcome of breast cancer in patients with type 2 diabetes, and to discuss the relationship of type 2 diabetes with clino-pathological features of patients with breast cancer. Materials and Methods: 126 operable breast cancer patients were enrolled into this study, who were coupling with diabetes and received surgical treatment during July 2002 to July 2007 in Shanghai breast cancer center. A control group of 334 breast cancer patients who had hypertension disease but not diabetes was defined. A comparison of clinico-pathological parameters was carried out between these two groups. Statistical software SPSS 12.0 was employed for survival either in univariate analysis or multivariate analysis. Results: Clinico-pathological characteristics were well-balanced between the patients in diabetes group and control group. As to survival, with a median follow-up time of 45 months, 24 cases recurred in the type 2 diabetes group, with the recurrence rate of 19%; while in the control group without diabetes but hypertension, 31 cases recurred only with the recurrence rate of 9.3%. A statistically significant difference in recurrence-free survival rate was shown between these two groups.

Time to Recurrence (months)

By univariate analysis, we revealed that the menopause status, pathological stage, grade, PR and HER2 expression, using chemotherapy or not and BMI had no effect on the recurrence-free survival; however, lymph node status, ER expression and with diabetes or not, were all associated with poor recurrence rate of breast cancer patients. We further used these parameters to explore their independent prognostic effect on the survival using multivariate analysis made by Cox hazard proportion model. The results showed that involved lymph node, ER negativity, with type 2 diabetes, were still the independent risk factor of poor prognosis. In subgroup analysis, we found that breast cancer patients with type 2 diabetes had a poor survival rate and higher recurrence rate compared with those patients of control group in subgroup populations with involved lymph nodes or with any status of ER. Furthermore, it was interesting that in breast cancer subgroup patients who had received chemotherapy, the risk of recurrence in cases with type 2 diabetes was much higher than that in cases without types 2 diabetes, which didn't happen in the patients who didn't receive chemotherapy. Discussion: Type 2 diabetes is an independent prognostic risk factor that indicating a higher possibility of recurrence and metastasis. It is reasonable to take the type 2 diabetes into account when evaluating the risk of breast cancer patients and decide the anti-cancer treatment strategy.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-32.