Frequently Asked Questions About Prostate Cancer
Early Warning Signs of Prostate Cancer
Q: Are there any warning signs for prostate cancer?
A: Unfortunately, there are no early warning signs for prostate cancer. Most cases seem to develop in men over 65, and at that point prostate cancer surpasses lung cancer as the most common cancer in men.
Prostate cancer has the benefit of a very accurate, inexpensive and easily performed early warning test. This is the prostate specific antigen (PSA) test. Your best bet, then, is to have a PSA test and a digital rectal exam every year after age 50. When men are screened annually with these tests, prostate cancer is caught early and the possibility of cure is greatest
Q: What is the Prostate?
The prostate is a male sex gland, about the size of a walnut. It produces a thick fluid that helps propel sperm through the urethra and out of the penis during sex.
Risk Factors for Prostate Cancer Development
Prostate Cancer is the most common type of cancer, after skin cancer, among men in the United States and Canada. Men of all ages, races, and ethnic groups can get prostate cancer. Your chances of developing Prostate Cancer do increase if:
- You are age 55 or older
- You are African American
- You have a father or brother with prostate cancer
More About These Risk Factors
It is well-established that prostate cancer incidence increases dramatically with increasing age. While a very unusual disease in men before age 50, rates increase exponentially thereafter.
Approximately 15% of men with a diagnosis of prostate cancer will be found to have had a first degree male relative (brother, father) with prostate cancer, compared to approximately 8% of the U.S. population.
1 It has been estimated that approximately 9% of all prostate cancers may result from heritable susceptibility genes.
2 Several authors have completed segregation analyses, and although a single, rare autosomal gene has been suggested to cause cancer in some of these families, the burden of evidence suggests that the inheritance is considerably more complex.
3,4 Further study has demonstrated that, controlling for all other tumor variables, treatment of the primary tumor is more likely to fail in men with a family history of prostate cancer.
Other evidence suggesting that the degree of cumulative exposure of the prostate to androgens is related to an increased risk of prostate cancer includes:
Neither BPH (Benign Prostatic Hyperplasia) nor prostate cancer have been reported in men castrated prior to puberty.
Androgen (hormone) levels generally parallel prostate cancer risk in various populations of men. Although there are conflicting data, a number of studies have demonstrated that levels of testosterone and, especially dihydrotestosterone, are highest in black males, of intermediate levels in white males, and lowest in native Japanese.
7,8,9 The risks for prostate cancer in these ethnic groups directly parallel these androgen levels.
Androgen deprivation in almost all forms leads to involution of the prostate, a fall in PSA levels, apoptosis (cell death) of prostate cancer and epithelial cells, as well as a clinical response in prostate cancer patients.
The risk of prostate cancer is dramatically higher among blacks, is of intermediate levels among whites, and is lowest among native Japanese. Survival is also related to ethnicity with 5-year survivals of whites with localized, regional, or metastatic prostate cancer being 94.7%, 86.6%, and 29.6%, respectively, compared to rates of 87.8%, 69.3%, and 22.7%, respectively, for blacks.
The explanation for this possible association between prostate cancer and dietary fat is unknown. Several hypotheses have been advanced including:
Dietary fat may increase serum androgen levels, thereby increasing prostate cancer risk. This hypothesis is supported by observations from South Africa and the United States that changes in dietary fat change urinary and serum levels of androgens.
Certain types of fatty acids or their metabolites may initiate or promote prostate carcinoma development. The evidence for this hypothesis is conflicting, but one study suggests that linoleic acid (omega-6 polyunsaturated fatty acid) may stimulate prostate cancer cells while omega-3 fatty acids inhibit cell growth.
- Steinberg GD, Carter BS, Beaty TH, et al.: Family history and the risk of prostate cancer. The Prostate 17(1): 337-347, 1990.
- Gronberg H, Isaacs SD, Smith JR, et al.: Characteristics of prostate cancer in families potentially linked to the hereditary prostate cancer 1 (HPC1) locus. Journal of the American Medical Association 278(15): 1251-1255, 1997.
- Carter BS, Steinberg GD, Beaty TH, et al.: Familial risk factors for prostate cancer. Cancer Surveys 11: 5-13, 1991.
- Schaid DJ, McDonnell SK, Blute ML, et al.: Evidence for autosomal dominant inheritance of prostate cancer. American Journal of Human Genetics 62(6): 1425-1438, 1998.
- Kupelian PA, Klein EA, Witte JS, et al.: Familial prostate cancer: a different disease? Journal of Urology 158(6): 2197-2201, 1997.
- Imperato-McGinley J, Gautier T, Zirinsky K, et al.: Prostate visualization studies in males homozygous and heterozygous for 5alpha-reductase deficiency. Journal of Clinical Endocrinology and Metabolism 75(4): 1022-1026, 1992.
- Isaacs JT: Hormonal balance and the risk of prostatic cancer. Journal of Cellular Biochemistry 16H(suppl): 107-108, 1992.
- Ellis L, Nyborg H: Racial/ethnic variations in male testosterone levels: a probable contributor to group differences in health. Steroids 57(2): 72-75, 1992.
- Ross RK, Bernstein L, Lobo RA, et al.: 5-alpha-reductase activity and risk of prostate cancer among Japanese and US white and black males. Lancet 339(8798): 887-889, 1992.
- Wu AH, Whittemore AS, Kolonel LN, et al.: Serum androgens and sex hormone-binding globulins in relation to lifestyle factors in older African-American, white, and Asian men in the United States and Canada. Cancer Epidemiology, Biomarkers and Prevention 4(7): 735-741, 1995.
- Peters CA, Walsh PC: The effect of nafarelin acetate, a luteinizing-hormone-releasing hormone agonist, on benign prostatic hyperplasia. New England Journal of Medicine 317(10): 599-604, 1987.
- Kyprianou N, Isaacs JT: Expression of transforming growth factor-beta in the rat ventral prostate during castration-induced programmed cell death. Molecular Endocrinology 3(10):1515-1522, 1989.
- Ries LA, Miller BA, Hankey BF, et al., eds.: SEER Cancer Statistics Review, 1973-1991: tables and graphs. Bethesda, Md: National Cancer Institute, 1994: 371. DHHS publication No. (NIH) 94-2789.
- Hill P, Wynder EL, Garbaczewski L, et al.: Diet and urinary steroids in black and white North American men and black South African men. Cancer Research 39(12): 5101-5105, 1979.
- Hamalainen E, Adlercreutz H, Puska P, et al.: Diet and serum sex hormones in healthy men. Journal of Steroid Biochemistry 20(1): 459-464, 1984.