Kidney Cancer Risk Factors

everal risk factors have been identified, associated with the development of kidney cancer, also called renal cell carcinoma (RCC).  The following discussion reviews several conditions observed in and surrounding kidney cancer patient populations.

Family History

Ho How is  the family history (FH) related to the incidence of kidney cancer?   The National Cancer Institute (NCI) strongly supports accurate family history-taking concerning cases of cancer.  The NCI defines first  degree relatives of a case  individual as  biological parents, biological siblings, and/or biological offspring.   Second degree relatives of a case  individual include grandparents, aunts, uncles, cousins, and grandchildren. The family history yields genotypic and phenotypic clues regarding the risk of inheriting various cancers.  Kidney cancer has been studied extensively regarding its relationship to the family history. ^[1]

A case-control study of 550 non-Asian patients with kidney cancer matched for age and sex with 550 non-Asian subjects without kidney cancer was carried out, revealing      detailed information about genotypic and phenotypic risk  of cancer, and medical  and life-style disease risk  factors obtained through person to person interviews. (Asians have lower rates of RCC; their exclusion from the study kept the RCC incidence rate high enough to maintain significant statistical assessment.)  The study findings: 

1. A person having  one first-degree relative with kidney cancer had a  significantly increased the risk of developing RCC.  

2. A person having  a first and another first- or a  second-degree relative with kidney cancer had  a three-fold increased risk of developing kidney cancer.

3. A FH of urinary tract cancers other than kidney cancer was not associated with kidney cancer risk; also, no relationship existed between a family history  of nonurinary tract cancers and  risk for kidney cancer.^[2]

Other Risk Factors

Some of the risk factors for kidney cancer identified in this study include cigarette smoking, chronic obesity,  history of hypertension, regular use of analgesics and amphetamines, and history of hysterectomy.

A Protective Effect

Protective action against kidney cancer has been found with regular intake of cruciferous vegetables (bok choy, broccoli, brussel sprouts, cabbage, cauliflower, canola/rape seeds, collard greens, mustard, radishes, turnips, rutabagas, etc.) ^[2]       

Check this link for a more complete listing of cruciferous vegetables and a description of the basis of the anti-carcinogenic properties of these "wonder" vegetables:

http://en.wikipedia.org/wiki/Cruciferous_vegetables

Smoking

Coordinated studies conducted in Australia, Denmark, Germany, Sweden and the United States evaluated the relationship between tobacco smoking and RCC.  A statistically significant association was observed for cigarette smoking, with current smokers having a 40% increase in risk relative risk (RR) = 1.4, 95% confidence interval (CI) 1.2-1.7.  

Long-term quitters (> 15 years) experienced some risk  reduction for  RCC relative to current smokers.  The findings of this analysis confirm cigarette smoking as a prime risk factor for RCC.^[3]

Physical Activity, Obesity, Amphetamine-based Diet Pills

Physical activity at work reduced the risk of kidney cancer in men.  In men, weight and BMI appeared at most to be weakly related to risk of kidney cancer.

Physical activity inversely correlated with kidney cancer in women.

Obesity increased the risk of kidney cancer among women.  

In women, higher adult weight and BMI, and high BMI at ages 30, 40, and 50 years, was  consistently associated with an increased risk of kidney cancer. Women with BMIs in the top 5% had a nearly 3-fold increase in the risk of kidney cancer.  The risk appeared to be greatest for women who were  in the top 10% of BMI during  their 40s.

Regular use of diet pills containing amphetamine increased the risk of developing kidney cancer.^[4]

Incidence of Kidney Cancer

The age-adjusted incidence rates for renal cell carcinoma between 1975 and 1995 for white men, white women, black men, and black women were 9.6, 4.4, 11.1, and 4.9 per 100,000 person-years, respectively.^[5]

Kidney cancer incidence rates increased steadily between 1975 and 1995, by 2.3% annually among white men, 3.1 % among white women, 3.9% among black men, and 4.3% among black women. Increases were greatest for localized tumors but were also seen for more advanced kidney cancers.^[5]

Increased detection of asymptomatic tumors by imaging procedures, such as ultrasound, CT, and MRI, does not fully explain the rising incidence of renal cell carcinoma. Other factors may be contributing to the rapid rise in numbers of renal cell cancers in the United States, particularly among blacks.^[5]   

A great deal of research is currently targeted at the cause and cure of kidney cancer.  Prevention is a critical area of work, medical and surgical treatment are moving forward-early detection, while the tumor is small and contained within the kidney offers the best shot at surgical cure. 

Hopefully the increases in detection of small kidney cancers reflects, in part, early diagnosis of this tumor, more amenable to surgical cure, and reflect a significant percentage of increase in the incidence.