Obesity and cancer risk

• obesity has been associated with increased risk for a number of different types of cancer:
  • evidence has been most consistent for endometrial cancer, breast cancer in postmenopausal women, and renal cell cancer
  • there have also been associations reported regarding obesity and colorectal, prostate and pancreatic cancer
  • it has been estimated that obesity is responsible for approximately 40% of endometrial cancers, 25% of renal cancers, and 10% each of colonic and breast cancers in Europe (2)
    • there is also evidence that obesity may promote the development of a more aggressive form of prostate cancer, resulting in higher recurrence rates after primary therapy and higher cancer mortality rates overall (3)
  • suggested mechanisms by which obesity may influence cancer risk include alteration in hormonal patterns, including sex hormones, insulin and insulin-like growth factor-1
    • with respect to endometrial cancer and obesity it has been theorised that the peripheral conversion of androstenedione to oestrone by adipocytes leads to a chronic low-level increase in oestrogen exposure and hence an increased risk of endometrial adenocarcinoma (4)

Reference:

1. Lipids. 1998 Nov;33(11):1055-9.
2. Bianchini F et al. Weight control and physical activity in cancer prevention. Obes Rev 3 (2002);. 5–8
3. Curr Opin Urol. 2005 May;15(3):167-71
4. Pavelka JC et al. Morbid obesity and endometrial cancer: surgical, clinical, and pathologic outcomes in surgically managed patients.Gynecologic Oncology 2004; 95 (3): 588-592