Geplaatst op 01 september 2008 - 15:11
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Geplaatst op 01 september 2008 - 15:17
Verder zijn er risicofactoren die het risico op een bepaald soort kanker verhogen. Die van prostaatkanker vind je hier.
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Geplaatst op 01 september 2008 - 18:33
Prostaatkanker en leeftijd:
Prostaatkanker en ethniciteit:
Poor health literacy has been implicated as a factor for advanced stage at presentation. Also of interest, African-American men aged 60 and older (but not other age groups) with clinically localized prostate cancer received aggressive treatment significantly less often than either Caucasian or Hispanic men.
Prostaatkanker en erfelijkheid:
The risk of prostate cancer is approximately two-fold elevated in men with an affected first degree relative (brother, father), compared to those without an affected relative. There is a trend toward increasing risk with a greater number of affected family members; men with two or three affected first-degree relatives had a 5- and 11-fold increased risk of prostate cancer, respectively in one case control study. Early age of onset in a family member also increases the risk.
Genome-wide association studies have been conducted to identify alleles associated with an increased susceptibility to prostate cancer. The studies rely upon the presence of genetic variations, known as single nucleotide polymorphisms (SNPs). This approach has identified multiple foci in the 8q24 region and the 17q region, as well as other in chromosomes.
Mutations or deletions in tumor suppressor genes (MMAC or PTEN) located on chromosome 10 may be important in the pathogenesis of prostate tumors. However, PTEN alterations appear to be primarily a late event, possibly influencing metastatic potential rather than prostate tumorigenesis.
The presence of BRCA1 or 2 mutations may increase the risk of developing prostate cancer two- to five-fold. In a cohort study that involved 3728 men from 173 breast-ovarian cancer families with BRCA2 mutations identified at 20 centers in Europe and North America, the estimated relative risk (RR) of prostate cancer among BRCA2 carriers was 4.65-fold greater than controls (95% CI, 3.48-6.22). At least some data suggest that prostate cancers in BRCA2 mutations carriers are more aggressive overall, with more advanced tumor stage, higher tumor grade, and shorter survival as compared to those diagnosed in noncarriers.
Prostaatkanker en voeding:
A diet high in animal fat may be an important factor in the development of prostate cancer. In particular, intake of large amounts of alpha-linoleic acid and low amounts of linoleic acid appear to increase risk; this combination is common in red meat and some dairy products.
A diet low in vegetables may be another risk factor for prostate cancer. A case-control study found a higher prostate cancer risk in men who consume less than 14 servings of vegetables weekly, compared with 28 or more servings (adjusted odds ratio 1.54).
Tomato based products are rich in lycopene, which has potent anti-oxidant properties. Well-conducted cohort studies have implicated lycopene-containing foods in lowering prostate cancer risk.
Phytoestrogens (flavones, isoflavones, lignans) are naturally occurring plant compounds that have estrogen-like activity. Genistein and daidzein, the predominant isoflavones in human nutrition, are derived mainly from soybeans and other legumes.
It is postulated that phytoestrogens such as those found in soy foods may reduce prostate cancer risk either via their inherent estrogenic properties (which favorably alters the hormonal milieu), or by inhibition of the enzyme 5-AR, which decreases concentrations of the more prostate-active androgen dihydrotestosterone. The higher intake of soy products among Asian men has been hypothesized to be one reason for the lower incidence of prostate cancer among these men.
Prostaatkanker en vitamines/supplementen:
The regular use of multivitamins does not appear to affect the risk of early or localized prostate cancer. However, two reports have observed an increased risk of advanced or fatal prostate cancer in men using relatively large amounts of multivitamins.
Increased selenium intake may be associated with a decreased risk of prostate cancer.
Compared with nonusers, men who consumed over 100 mg of supplemental zinc daily had a 2.29-fold increased risk of prostate cancer; the RR was 2.37 in those who took zinc for 10 or more years.
In a meta-analysis examining the association of dairy product and calcium intake and prostate cancer risk, men with the highest intake of dairy products (relative risk 1.11, 95% CI 1.0 to 1.22) and calcium (RR 1.39, 95% CI 1.09 to 1.77) were more likely to develop prostate cancer than those with the lowest intake.
Prostaatkanker en obesitas/hormoonhuishouding:
Serum concentrations of testosterone, dihydrotestosterone (DHT), and other active androgen derivatives obtained prior to diagnosis were NOT associated with an increased risk of subsequent prostate cancer. In addition, no association was seen with pre-diagnosis serum levels of estrogens (estradiol, free estradiol).
Most but not all series support a relationship between higher serum insulin levels, waist-hip ratio (WHR, a marker of body fat distribution) and prostate cancer risk. In a representative case control study of Chinese men, those in the highest tertiles of WHR and serum insulin levels had an 8.55-fold higher risk of prostate cancer than men in the lowest tertiles of both factors.
Observational studies provide conflicting data as to the association of obesity with prostate cancer risk. More consistently, a correlation between body mass index and aggressive prostate cancers as well as prostate cancer mortality has been observed in several studies. The largest report analyzed data from 3162 men who were treated with radical prostatectomy; 19 percent were obese, and they had significantly higher grade prostate cancer and a higher risk of recurrence. Higher body mass index was related to black race, and race was an independent predictor of recurrence in multivariate analysis. The authors concluded that obesity might represent a risk factor for tumor progression rather than initiation.
Although there are many benefits from regular physical exercise, it is not clear that a reduced incidence of prostate cancer is among them.
Prostaatkanker en andere factoren:
Long duration regular use (30 or more pills per month for five or more years) of either NSAIDs (relative risk 0.82, 95% CI 0.71 to 0.94) or adult-strength aspirin (RR 0.85, 95% CI 0.73 to 0.99) was associated with a significantly reduced incidence of prostate cancer.
On the other hand, a meta-analysis that included 12 published case-control or cohort studies concluded that there may be a modest protective effect of aspirin (odds ratio 0.9, 95% CI, 0.82-0.99) but that the data for nonaspirin NSAIDs were too heterogeneous for meta-analysis. The lack of prospective trials makes it difficult to draw conclusions in this area.
A case-control study utilizing clinical and demographic data on 443,805 patients cared for at 10 Veterans Administration Medical Centers (VAMCs) in four states, 26,139 of whom were diagnosed with prostate cancer. Statin use prior to the diagnosis of prostate cancer was associated with a significant protective effect for prostate cancer (odds ratio [OR] 0.464, 95% CI 0.45 to 0.48) after controlling for age, body mass index, smoking, diabetes, and race.
In a study which compared men under the age of 70 who had prostate cancer and age-matched controls, men who had five or more ejaculations per week while in their 20s (but not their 30s or 40s) had a significantly lower risk of prostate cancer (odds ratio 0.66) than those who had fewer ejaculations.
A report from the Health Professionals Follow-up Study compared men who developed prostate cancer (n = 1449) and controls of a similar age group who had similar ejaculatory frequency but no prostate cancer. Although most categories of ejaculation frequency were unrelated to prostate cancer risk, men who reported 20 or more monthly ejaculations during their 40s, within the past year, or averaged across a lifetime had a significantly lower risk of prostate cancer compared to men having 4 to 7 ejaculations per month (odds ratios of 0.67, 0.49, and 0.67, respectively.
Several case-control and cohort studies, as well as two meta-analyses suggest a significant but modest increase in the risk of prostate cancer in men with prostatitis (RR = 1.6), and in those with a history of syphilis or gonorrhea (RR = 1.4).
In one case control study exposure to ultraviolet (UV) light had a protective effect on the development of prostate cancer. Furthermore, cases with low UV exposure developed at a younger median age (68 versus 72 years old). A similar associated has been reported by others.
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