Obesity and prostate cancer research

The authors of the manuscript entitled " Obesity, diabetes and aggressive prostate cancer hormone– naïve at initial diagnosis [1] published in this issue performed a retrospective analysis of 266 patients who underwent prostate biopsies for suspected pros-tate cancer (PCa). Their results suggest that obesity and diabetes mellitus type II (DMII) are associated with more aggressive PCa (defined as higher biopsy Gleason score), which could have an impact on pa-tients' outcome. These results are relevant, since they discuss the association of two major public health concerns for middle–aged and older men. Obesity is a growing epidemic , especially in industrialized countries, which is generally accepted to be correlated with cardio-vascular disease, diabetes mellitus type II and other diseases. In 2003, it has already been shown that body weight was associated with increased overall cancer and PCa–specific death rates [2]. In light of this, it has already been suggested that lifestyle and diet could play an important role in the development of PCa, which is based on the observation that Caucasians have much higher rates of PCa when compared to Asians. Higher rates of PCa have been found in Asians who have migrated to the USA in comparison to their home–land counterparts, which could partially be explained by diet and lifestyle adjustments [3]. Since then, there has been an increasing interest in understanding the role of obesity in the development and outcome of PCa. Indeed, several studies have shown an association between BMI (kg/m²) and more lethal disease, with a meta–analysis by Cao et al. showing a 15–21% increased risk of fatal PCa or biochemical recurrence in obese PCa patients [4]. Despite of being interesting, these results only show that there is an association between obesity and PCa and do not provide a causal relationship for this association. There could be multiple explanations for these observations. It could be speculated that PCa diagnosis is delayed in obese patients because digital rectal examination is less sensitive and patients get less PSA testing, since their primary health care is focused on their weight problems and associated (cardiovascular) diseases. Furthermore, there is an inverse relation between PSA levels and BMI, which is suggested to be caused by hemodilution [5]. When diagnosed, curative treatment could be less efficient in obese patients as well. During surgery, abundant subcutaneous and visceral fat could hinder careful dissection, possibly leading to higher rates of positive surgical margins [6]. As the …