Obesity Cancer Kidney

An estimated 80 to 85 percent of all kidney cancers are renal cell carcinomas (RCCs). For the most part, the terms kidney cancer, renal cancer and RCC tend to be used interchangeably in research reports.

Kidney Cancer - Obesity and Kidney Cancer

In 2002, the BBC reported an alarming rise in incidence of kidney cancer. Over the span of just a decade, UK rates of RCC showed a 22 percent increase. A study published in the Journal of the American Medical Association (2001) reports that that U.S. kidney cancer rates have increased from 2 to 5 percent a year since the 1970s. Kidney cancer now increases at a faster rate in women than breast, skin or lung cancers.

While medical researchers may be tempted to conclude that kidney disease is one of the effects of obesity, establishing obesity as a direct cause is premature.

The Obesity-Kidney Failure Link

Researchers at New York’s Memorial Sloan-Kettering Cancer Center (2010) have found a clear link between body mass index (BMI) and clear-cell RCC. In numerical terms, every one-point increase in BMI increases RCC risk by 4 percent.

Within their study of 1,640 patients, obese patients with a BMI above 30 had a 48 percent higher risk of RCC. Although the typical treatment for patients with small kidney tumors is regular monitoring, Sloan-Kettering researchers concluded that obese patients with these tumors should be subject to more aggressive measures.

Researchers have just begun to establish the obesity-kidney disease link. Prior to this decade, smoking was thought to be the strongest causal factor, with the combination of obesity and smoking further increasing the risk of developing RCC.

Researchers from the National Cancer Institute (2001) have been able to isolate the link between obesity and RCC independently of other factors such as smoking or hypertension, although both of these factors on their own have also been shown to increase the risk of RCC. They also find no correlation between obesity and renal pelvic cancer, a less common form of kidney cancer.

Estrogen and insulin-like growth factor rank high among the list of suspected causes of the alarming increase in kidney cancer rates. Since fat cells produce estrogen, researchers hope to determine whether the presence of estrogen in higher proportions in obese people might at least partially explain the added risk of RCC in obese patients.

Kidney Cancer Symptoms

If you’re overweight, smoke or have high blood pressure, see your doctor about lifestyle changes, particularly if you’re experiencing some of these kidney cancer symptoms:

  • A lump in the abdomen
  • Blood in the urine
  • Fever
  • Increased fatigue
  • Pain in the lower back not due to injury
  • Sudden weight loss
  • Swelling in the legs and/or ankles.

Even if you’re experiencing none of these kidney cancer symptoms, if you’re among those who are at high risk, ask your doctor to make screening for RCC a part of your annual checkup. Early detection remains the best means of avoiding serious outcomes.


BBC News World Edition. (2002). Obesity linked to kidney cancer. Retrieved July 1, 2010, from: http://news.bbc.co.uk/2/hi/health/2273765.stm.

Chow, W. H., Gridley, G., Fraumeni, J. F., J r.