nursing.elitecme.com Page 47 Complete Your CE Test Online - Click Here CANCER PREVENTION AND RISK REDUCTION Skin cancer prevention and risk reduction Because we know that UV rays cause cancer, nurses can counsel patients to avoid tanning beds, cover their skin and eyes (including hats and UV-blocking sunglasses), and seek shade, especially when outside during the times of day when UV rays are strongest. This is usually between the hours of 10AM and 4PM. Encourage patients to learn about their local “UV index” which describes on a numeric scale how strong UV radiation is in a particular area on specific dates. The daily UV index for an area can be found online, in some weather forecasts, or via an “app” for smart phones from the Weather Channel, among others (see “Resources for Patients”). Different skin types are at different risks It is important to let patients and families know, that despite the risk strata, people with darker skin can also get skin cancer and that UV exposure increases that risk. Information about UV index can be an important tool for everyone, but patients who are most susceptible to skin cancer should be given repeated counseling regarding the topic. People who spend a lot of time outdoors, those with a family history of skin cancer, and those who have had blistering sunburns in the past should avoid such exposures in the future (see also “Ultraviolet Radiation” in “Risk Factors” section). The Canadian Dermatology Association uses the Fizpatrick skin type classification to help stratify skin cancer risk. Skin can be classified from Type-1 to Type-6, depending on genetic disposition, reaction to sun exposure, and tanning habits. Type-1 and Type-2 are at the greatest risk of skin cancer. Although there are more details to determine exactly who fits into which category, here is a general description of the skin types (skin color refers to unexposed skin) [58, 256]: ● ● Type I: Always burns, blisters and peels, never tans; light reddish skin; freckles easily. ● ● Type II: Usually burns and peels, and then tans; very pale skin; some freckling. ● ● Type III: May burn and peel, but tans well; pale with beige tint; may have a few freckles. ● ● Type IV: Rarely burns and tans well; light brown skin. ● ● Type V: Very rarely burns, tans easily, brown skin. ● ● Type VI: Very rarely burns, tans easily, very dark skin. When UV exposure is unavoidable and other measures are unacceptable, using a broad-spectrum sunscreen of SPF 30 might help reduce the risk of DNA damage in the skin as well as reduce the risk of sunburn [300]. Sunscreens are often applied too sparingly and may come off with sweating, so remind people to use a “palm-full” and to re-apply every two hours while in the sun. An interesting point here is that, although some groups strongly recommend it, the National Cancer Institute reports that the evidence for sunscreens protecting against skin cancer is still less than adequate, in part because of the years of follow-up required to show differences, problems with reporting, and other influences on skin cancer risk [147]. In the U.S., broad-spectrum sunscreen has been around a much shorter time than the older, less protective types, so there has been less time to study it. Colorectal cancer prevention Screening with colonoscopy or sigmoidoscopy finds precancerous lesions that can be removed, and as such, serves dual role for prevention and screening. Every year or two, reports pop up that aspirin reduces the risk of colorectal cancer. Keeping in mind the limitations of these studies, and the fact that the news reports rarely mention dose requirements or the harms of long-term aspirin use, it is understandable that people are interested in this as a possible method of cancer prevention. The USPSTF did a thorough review of evidence on the effects of aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs) on colorectal cancer (CRC) incidence and mortality. They looked at the efficacy of aspirin and NSAIDs in reducing CRC, adenomatous polyps, and cancer incidence. They also looked at mortality, including the dose-dependent effects and harms linked to aspirin and NSAID use in healthy adults. The USPSTF concluded that short-term aspirin does not reduce CRC incidence, but found some evidence that long-term use of higher-dose aspirin (in the range of 300-325mg per day) and NSAIDs are linked with lower CRC incidence. For example, looking at the long-term Nurses’ Health Study, the USPSTF reported that those who took more than 14 aspirin tablets (325mg tabs) a week for more than ten years had a CRC risk of about half what would have been expected. They also found that aspirin and NSAIDs reduce colorectal adenomas, especially at the higher doses. It is possible that high-dose aspirin could reduce CRC deaths, but most of the studies were not able to show that. Even the Nurses’ Health Study did not show a reduction in deaths from CRC; a lot of nurses took more than 14 aspirin tablets per week for longer than ten years [285]. A 2016 publication by Cao et al. showed a more modest reduction in CRC incidence with lower-dose aspirin use as well as a small reduction in other GI cancers, when aspirin was taken for at least six years [61]. However, the USPSTF did find evidence of significant harms to aspirin use, including dose-related incidence of gastrointestinal bleeding and hemorrhagic stroke. They reported on one meta-analysis (of 16 randomized controlled trials) that looked at GI complications, and found an odds ratio of 5.36 for perforations, ulcers, and bleeding with the use of NSAIDs. Studies that looked at NSAIDs for other purposes have also found an increase in acute renal failure in those over 65, and elevations in blood pressure. These complications might be more pronounced in the older adult population, which is the group that most stands to benefit from CRC prophylaxis [285]. The USPSTF specifically recommends against using aspirin and NSAIDs for only colorectal cancer prevention in people who are at average risk of CRC [285]. However, in late 2015, the USPSTF released a draft guideline which recommends prophylactic aspirin for adults in adults aged 50 to 59 years old who are at a ten percent or greater risk of CVD over a ten-year period, which also offers CRC risk reduction to those same people. Adults age 60 to 69 can take aspirin if they meet the same CVD risk criteria and still do not have an increased risk of bleeding, assuming that they have a life expectancy of at least ten years. The USPSTF reported insufficient evidence to balance risks and benefits of adults younger than 50 or older than 69 [286]. Of note, the American Cancer Society has no recommendations at this time for use of NSAIDs or aspirin for people at average risk of CRC. It is interesting that the U.S. Food and Drug Administration approved the NSAID celecoxib for reducing polyps in people with familial adenomatous polyposis (FAP). This drug may cause less GI bleeding than other NSAIDs, but it might also increase heart attack and stroke risk [20]. Of course, the risk-benefit ratio is different in people with FAP because of their extremely high risk of CRC. Breast cancer risk reduction for women at high risk Women known to have significantly increased breast cancer risk can use chemoprevention in the form of tamoxifen (for premenopausal women) or raloxifene (for postmenopausal women), which have both been FDA-approved for this purpose. Studies show an overall relative risk reduction of about 38% for this preventive measure. This means that woman with an 8% risk of breast cancer in the next five years (which is pretty high) would see their absolute risk cut to about 5% with this drug treatment. But healthy women at age 60 would have about a 1.7% chance of breast cancer over the next five years, and a 38% risk reduction would drop their absolute risk to about 1.05%. The absolute benefit is clearly much less for women at average risk of breast cancer [34]. Tamoxifen only decreased estrogen receptor-positive cancer and DCIS, but the effect lasted for 16 years after starting tamoxifen (11 years after finishing the 5-year course). These drugs also have risks, which is another reason they are not recommended for general use in breast cancer prevention. Tamoxifen can cause symptoms of menopause and slightly increase the risk of