AOCNS Practice Test Answers and Explanations

1. D: Prostate cancer is the second leading cause of death from cancer in American men despite the fact that only about 3% of those afflicted die of the disease. This is of great interest since about 20% of American men will be diagnosed with the disease during their lifetime. The disease appears to be indolent among older men and often they die of another disease before the prostate cancer becomes life-threatening. The disease tends to be more aggressive among younger men, possibly related to testosterone levels. African American men have a higher incidence and mortality rate than Caucasian men. This may be partially related to delay in diagnosis. Risk factors include advancing age, family history of the disease, ahigh-fat diet, and perhaps obesity. Genetic factors are suspected to increase risk but no definite genes have as yet been identified.

2. C: Preventive measures for those at high risk of developing cancer have been the subject of a variety of clinical studies. Bilateral mastectomy, though extreme, has been used for those women who have developed a cancer in one breast and/or have a very strong family history of the disease, usually two or more direct relatives such as mother and sister. Women with the BRCA1 and BRCA2 genes may be candidates as well. Tamoxifen, a drug that interferes with estrogen activity, has been used for 30 years to treat breast cancer and for 10 years to decrease the incidence in high-risk individuals. Raloxifene hydrochloride is a selective estrogen receptor modulator (SERM) originally developed to treat osteoporosis but has been found to be useful in breast cancer prevention, with possibly an even greater efficacy than tamoxifen. Vitamin B12 and folic acid do not prevent breast cancer.

3. B: Behavioral changes, though often difficult to maintain, may be the first line of defense in cancer prevention. Tobacco use, for example, has been associated not only with an increased risk of lung cancer but many other types of cancer as well. Recently dietary measures to avoid obesity have been the subject of several cancer prevention studies. Persuading people to go for proven screening tests such as Pap smears, colonoscopies, and PSA levels may also play a larger role in detecting precancerous lesions and lead to earlier treatment. Newer techniques, such as breath analysis for lung cancer, testing for blood tumor markers, or urinary DNA for bladder cancer, may increase the potential of this approach. According to the Institute of Medicine's report in 2003, 60,000 cancer deaths could be prevented in the United States and 100,000 new cases reduced by 2015 if behavioral changes and better access to screening tests occur widely.

4. A: Most clinical studies of high-fiber diets have concluded that this dietary change may reduce the incidence of colon cancer and colonic adenomatous polyps, a known precursor of cancer of the large bowel. One study of 500,000 individuals in 10 countries documented a 25% decrease in the incidence of colon cancer in those individuals who ate 33 g/day of fiber versus those who ate 12 g/day. Low selenium levels have been correlated with an increased risk of colon cancer, although the mechanism is uncertain. Both calcium and nonsteroidal anti-inflammatory drugs (NSAIDs) may also have protective properties. Adenomatous polyps, especially those greater than 1 cm in size, are potential precursors of colon cancer and should be removed via colonoscopy. Those individuals with familial polyposis have a very high risk of colorectal cancer and colectomy is often required for prevention.

5. B: The new vaccine Gardasil is effective against the two types of HPV that cause 70% of cervical cancers and 90% of genital warts. Originally intended for girls prior to sexual activity, the indication has now been expanded to the 9- to 26-year-old age range. There are about 30 types of HPV, so the vaccine may protect against those types that have not yet infected an individual. It is given in three doses over six months. Since the vaccine only protects against 70% of cervical cancers, the need for Pap smears is not eliminated. Side effects include pain or erythema at the injection site, headache, fever and occasional dizziness, vomiting, or fainting.