The impact of lipomatous tumors on type 2 diabetes: are adipose-derived tumors metabolically active?

BACKGROUND: The metabolic and immunologic properties of adipose tissue are linked to the pathogenesis of type 2 diabetes mellitus. Lipomatous tumors, such as liposarcomas, are rare but can reach significant size. We hypothesized that some lipomatous tumors are metabolically active and can alter systemic glucose homeostasis. METHODS: We performed a retrospective study of patients who underwent resection of a lipomatous tumor at a tertiary cancer referral center (2004-2015). We divided patients into nondiabetics, well-controlled diabetics (hemoglobin A1c [HbA1c] < 7), and poorly controlled diabetics (HbA1c ≥ 7). We compared patient demographics, tumor characteristics, and measures of glycemic control among these groups before and after tumor resection. RESULTS: We reviewed 217 operations for lipomatous tumors. No differences were observed in tumor characteristics in patients with and without diabetes. However, tumor characteristics differed significantly between the well-controlled and poorly controlled diabetics groups. Patients with poorly controlled diabetes had larger tumors that were more likely to be malignant, retroperitoneal, and well-differentiated. Tumor resection had no detectable impact on diabetes, as assessed by HbA1c, and requirement for diabetic medications. CONCLUSIONS: Poorly controlled diabetes was linked to the presence of large, malignant, and retroperitoneal lipomatous tumors. However, in limited follow-up, no detectable impact of tumor resection was apparent on glycemic control. These data suggest that most lipomatous tumors do not exert a clinically relevant impact on glucose homeostasis.

Association of Bariatric Surgery Status with Reduced HER2+ Breast Cancers: a Retrospective Cohort Study.

BACKGROUND: Bariatric surgery is associated with a reduced risk of developing certain malignancies, particularly in women. However, the impact of bariatric surgery on tumor characteristics, cancer treatment, and oncologic outcomes is unknown. METHOD: In a retrospective cohort study, 42 subjects diagnosed with breast cancer after bariatric surgery (1989-2014) were matched to 84 subjects with breast cancer (1984-2012) who did not undergo bariatric surgery, based on age, body mass index (BMI), and menopausal status at the time of breast cancer diagnosis, as well as the date of cancer diagnosis. Medical records were reviewed for cancer and bariatric endpoints. Statistical analysis was performed using mixed effects regression models, generalized estimating equation, conditional logistic regression, and Fisher's exact tests. RESULTS: Women who developed breast cancer after bariatric surgery presented at an earlier stage compared to non-operated, obese controls. In the bariatric surgery group, there were fewer tumors with human epidermal growth factor receptor 2 overexpression (HER2+) (OR 0.16 (0.03-0.76); p = 0.02), with no significant differences seen in estrogen and progesterone receptor positivity. No HER2+ cancers were found in patients who underwent Roux-en-Y gastric bypass (OR 0.00 (0.00-0.43); p = 0.002). On multivariate analysis, bariatric surgery status remained associated with reduced HER2+ breast cancers (OR 0.18 (0.03-0.99); p < 0.05). At a mean follow-up of 5 years, bariatric surgery was associated with trends toward reduced cancer-specific and all-cause mortality. CONCLUSIONS: Bariatric surgery is associated with reduced HER2+ breast cancers, suggesting that bariatric surgery can influence breast cancer characteristics and, potentially, tumor biology.