ASCO: Leptin & High BMI May Reduce Her2+ Survival

[1rarebird]

Impact of BMI on clinical outcome of HER2-positive breast cancer American Society of Clinical Oncology Meeting, June 2010

The current retrospective study was designed to examine the influence of body mass index (BMI) on outcomes of women with HER2 overexpressing breast cancer treated with trastuzumab (Herceptin). Obesity and HER2 overexpression are known to be linked with poor prognosis in breast cancer patients. Recent studies have suggested the existence of functional crosstalk between HER2 and leptin, a hormone correlated with excess fat. In particular, stimulation with leptin can transactivate HER2 and activate its downstream signaling. Chronic exposure to leptin increases HER2 stability in both the presence or absence of Herceptin. The current study included 155 patients with HER2-positive status treated with Herceptin for early stage or metastatic breast cancer during the period 2003 to 2008. Patients were divided into normal, overweight, and obese categories according to BMI, following WHO guidelines. Overall survival and time to progression were estimated by the Kaplan-Meier method and comparisons were made using the log-rank test. One hundred and three 103 patients were treated with adjuvant Herceptin. Of the overall study group, 12.5% relapsed during the study period. Among the relapsed patients (in which breast cancer progressed), 31% were overweight and 23% were obese. Also within this subgroup, overall survival and time to progression decreased with increasing BMI: the median overall survival for normal weight patients was 40 months, whereas it was 36.5 months for overweight and 31 months for obese patients. Similarly, median time to progression was 11 months for normal weight patients, whereas it was eight months for overweight and five months for obese patients (p=0.0351). Fifty-two patients received chemotherapy plus Herceptin for metastatic disease. In this population, 33% of the patients were overweight and 15% were obese; median overall survival was 65 months and time to progression 10.5 months. Again among this subgroup, decreased overall survival and time to progression were found with increasing BMI: median overall survival for normal weight women was 67 months, whereas it was 54 for overweight and 39 for obese patients (p=0.0010); median time to progression was 12, 7.5, and 7 months, respectively (p=0.0442). Reduced survival associated with increasing BMI was also found when the overall population was studied according to hormone receptor and menopausal status. The authors conclude that obesity predicts worse outcomes in HER2-positive patients. Furthermore, the results validate previous laboratory studies suggesting that leptin can impair response to Herceptin in breast cancer cells.

[schoolteacher]

Thanks for posting this article.

Amelia

[1rarebird]

You are welcome, Amelia.

Even though the greater risk appears to be there for us Her2+ folks, I am taking this information as a positive message and one that I can work on by myself without doctor involvement. I can do some things to lower my BMI and perhaps it will help me in the long run.
bird