Disease Control Bulletin: March 2000
- Colorectal Cancer
- Folic Acid Prevents Neural Tube Defects
- New HIV Surveillance
- Selected Reportable Diseases 1/1/2000–3/31/2000
- Tick Testing for Lyme Disease Discontinued
- Improved Laboratory Services for Tuberculosis
Colorectal Cancer: Silent. Prevalent. Preventable.
Recent research indicates that the public is poorly informed about colorectal cancer, lacking basic information about risk, prevention, and the benefits of screening for this second leading cause of cancer death. In addition, health care providers don’t recommend colorectal cancer screening as consistently as other cancer screenings such as mammograms.
Colorectal cancer begins as precancerous polyps that are detectable and removable, providing an almost certain cure; however, only 35 percent are diagnosed at the polyp stage.1 Given estimates that up to 50 percent of these cancer deaths could be prevented through lifestyle changes and screening,2 this lack of awareness and early detection is concerning.
COLORECTAL CANCER INCIDENCE AND MORTALITY
In Vermont, colorectal cancer is the third most commonly diagnosed cancer in men (after lung and prostate), and the second most common in women (after breast). In 1999, an estimated 129,400 Americans were diagnosed with this disease.3 In Vermont, approximately 184 women and 151 men are diagnosed with colorectal cancer each year.
Colorectal cancer is the second leading cause of cancer death for men and women combined. In 1999, an estimated 56,000 Americans died of colorectal cancer, including approximately 132 Vermonters.
Contrary to popular opinion, colorectal cancer strikes men and women almost equally. However, while women nationwide have slightly lower rates than men, Vermont women’s rates are significantly higher than the national average. National data indicates that African Americans have the highest rates of any major racial/ethnic group, tend to be diagnosed at later stages, and have worse survival rates at any given stage.5 Early detection and removal of precancerous polyps is key to reducing morbidity and mortality. Almost all colorec-tal cancers begin as adenomatous polyps, which have the potential to become malignant but are most often benign when detected. In early stages, colorectal cancer is largely asymptomatic, but in later stages can produce symptoms such as rectal bleeding, abdominal, pelvic, or back pain, and changes in bowel habits. When diagnosed and treated at the early and localized stage, the five year survival rate is 90 to 95 percent. However once the cancer has progressed to a stage where symptoms are likely to develop, the five year survival rate falls to 66 percent when diagnosed ata regional stage and 8 percent when diagnosed at an advanced stage.6
The main risk factor for colorectal cancer is age, and all people age 50 and over are considered to be at elevated risk. Seventy five percent of cases occur in people with no known risk factors other than age. Other non-modifiable risk factors include havinga first degree relative with colorectal cancer and having a medical history of inflammatory bowel disease. Genetic syndromes such as hereditary nonpolyposis col-orectal cancer (HNPCC) and familial adenomatous polypo-sis (FAP) account for less than 10 percent of cases. Men and women are at similar risk for these inherited forms, which cause the cancer to develop at an early age.
SCREENING AND PREVENTION
In 1996, a national group of experts was convened by the U.S. Agency for Health Care Policy and Research to develop clinical practice guidelines. The guidelines have been endorsed by the American Cancer Society, American College of Gas-troenterology, American Society of Colon and Rectal Surgeons and seven other specialty groups. The guidelines recommend that all people be screened beginning at age 50 and those at higher risk because of family history, genetic syndromes, or inflammatory bowel disease be screened at an earlier age. Because there are several methods of screening, each of which has advantages and disadvantages related to cost, effectiveness, complexity, risk and acceptability, the guidelines suggest using one of the methods listed below.
Colorectal Cancer Screening Guidelines
- Sigmoidoscopy every 5 years, or
- FOBT annually and sigmoidoscopy every 5 years, or
- Colonoscopy every 10 years, or
- Double-contrast barium enema every 5-10 years.
While age and family history are risk factors that can’t be modified, there are several factors that can reduce an individual’s risk. The science on prevention is still evolving, however, diet and exercise have consistently been shown to be related to colorectal cancer risk.
There is disagreement about the role of fiber; most studies have shown that both consumption of high levels of red meat and low levels of vegetables increase risk.7 Alcohol and smoking are also associated with an increased risk. In terms of protective behaviors, exercise has been shown to reduce risk for colon cancer. Non-steroidal anti-inflammatory drugs have also showna protective effect, anda recent meta-analysis by Dr. Walter Willett of Harvard suggests that daily use ofa multivitamin with folic acid can reduce risk as well.
While research continues on preventive strategies including possible protective benefits of calcium, vitamin D, and hormone replacement therapy, screening is known to prevent development of colorectal cancer by detecting and removing pre-cancerous polyps. The 1996 Vermont Department of Health Primary Care Preventive Practices survey indicated that among physicians, only 47 percent in family practice, 54 percent in internal medicine, and 60 percent in Ob/ Gyn practices routinely recommended FOBT screening to patients at normal risk. The percentage of physicians recommending screening with sigmoidoscopy was even lower, with 11 percent of internal medicine and3 percent of family practice physicians routinely referring patients at normal risk for this screening procedure. Reasons most commonly cited for not recommending sigmoidoscopies included lack of patient acceptance, high cost to patient, anda patient visit that was for acute or episodic care only.
PUBLIC AWARENESS AND ATTITUDES
The 1997 Behavioral Risk Factor Surveillance System data show that only 30 percent of men and 40 percent of women in Vermont have ever had a FOBT.8 Recent research indicates a serious lack of awareness and understanding about screening to prevent colorectal cancer, which may bea factor in the low rates of compliance with this test.
A national phone survey conducted for last month’s kickoff of Colorectal Cancer Awareness Month found high awareness of cancer as “a serious disease that can be fatal,” but low awareness of colorectal cancer asa type of cancer. When asked what they could do to help protect themselves from colorectal cancer, one-quarter of respondents could not name even one thing. Most of those who did name an action focused on broad preventive measures such as eating a better diet or more fruits and vegetables. Only four percent mentioned getting screened.9 Federal agencies recently conducted a series of focus groups with Americans ages 50 and older to learn about public awareness as well as barriers and motivators to screening. They found that many participants had misconceptions about testing for colorectal cancer, including not understanding the role of FOBT and confusing colorectal cancer screening with prostate cancer screening. They believed either that colorec-tal cancer was unimportant, as they had heard so little about it, or perceived that it was worse (faster spreading and deadlier) than other cancers. Health care providers were clearly identified by the focus groups as an important source of influence on screening behavior. However, participants reported receiving little or no information about colorectal cancer from them. This lack of communication was often interpreted as indicative that screening was a low priority or ineffective.10
Suggestions for increasing screening rates in your practice:
- Make counseling a priority. Stress the importance of screening to your patients and office staff.
- Talk with your patients about screening. Patients are more likely to get screened if they’re knowledgeable about it and believe it’s important.
- Provide information about the procedures, risks, and benefits of the different screening options, and share the decision-making process with your patient.
- Develop a reminder system to prompt your staff and patients about recommended screenings.
- Ries L, Kosary C, Hankey B, Miller B, Edwards B. SEER Cancer Statistics, 1973-1995. National Cancer Institute, Bethesda, MD; 1998.
- Tomeo CA et al. Harvard Report on Cancer Prevention: Volume 3. Cancer Causes Control 1999;10(3):167-80.
- Cancer Facts & Figures-1999. American Cancer Society, Inc., Atlanta, GA; 1999.
- Cancer in Vermont: A report of 1994-1996 cancer incidence data from the Vermont Cancer Registry. VT Dept of Health, Burlington, VT, 1999
- Landis SH et al. Cancer Statistics, 1999. Ca-Cancer J Clin 1999;49: 8-31.
- Colorectal cancer: The importance of early detection. Centers for Disease Control and Prevention, Atlanta, GA; 1999.
- Food, Nutrition, and the Prevention of Cancer:a Global Perspective. World Cancer Research Fund and the American Institute for Cancer Research, 1997.
- Vermont Behavioral Risk Factor Surveillance System 1997. VT Dept of Health. Burlington, VT.
- Cancer Research Foundation of America, unpublished report.
- Beeker C, Kraft JM, Southwell BG, Jorgensen CM. Colorectal cancer screening in older men and women: Qualitative research findings and implications for intervention.J Comm Health (in press).
- American Cancer Society resources, data and pamphlets: <http:// www.cancer.org> or (800) ACS-2345.
- CRC screening guidelines: <http://www.gastro.org/colcancer/index.html> or (301) 654-2055.
- CDC Screen For Life campaign, brochures and posters: <http:// www.cdc.gov/cancer/colorctl/awareness.htm> or (888) 842-6355.
- The Harvard Center for Cancer Prevention: <http://www.hsph.harvard.edu/ cancer> or (617) 432-0038.
Folic Acid Prevents Neural Tube Defects
Taking folic acid, also known as folate, is a simple and important weapon in fighting birth defects. Consumption of 400 µg of folic acid a day before and during pregnancy could prevent up to 70 percent of neural tube defects, including spina bifida and anencephaly. Research also suggests that taking folic acid before and during pregnancy may decrease the incidence of facial clefts and congenital heart defects. Although enriched grain products like cereal are fortified with this important nutrient, it is difficult to consume enough through diet alone.
The Centers for Disease Control and Prevention1 and the March of Dimes recommend that all women of childbearing age (adolescence through menopause) consume 400 micrograms of folic acid per day by taking a vitamin pill. Women who have had a pregnancy affected with a neural tube defect should take 10 times this amount starting at least one month prior to any subsequent pregnancy and continuing for three months, under the direction of their health care provider.
WHAT IS A NEURAL TUBE DEFECT?
The neural tube is the embryological beginning of the spinal cord and the brain in the earliest phase of prenatal development. By 28 days after conception, the neural “plate” has folded and sealed longitudinally to makea tube; if the tube fails to close completely, neural tube defects result. These defects, which include spina bifida, anencephaly, and encepha-locele, are among the most prevalent and serious birth defects. Anencephaly is fatal in the newborn period. Babies born with spina bifida may experience a range of disability and medical complications, from mild to very severe.2 About 2500 U.S. infants are born each year with neural tube defects and an unknown number of pregnancies end in miscarriage, stillbirth, and abortion. Data from the Vermont Vital Statistics and from the Vermont Triple Markers Prena-tal Screening Program3 indicate that, for the years 1991 to 1996, there were a total of 42,081 Vermont births and 36 pregnancies were known to be affected. This means the prevalence rate was.86 per 1000 births, similar to the prevalence in New England.
WHAT IS THE SCIENTIFIC SUPPORT FOR FOLIC ACID?
Neural tube defects have long been believed to be caused bya combination of factors; however, these factors and their relationship to each other have not been well understood. Diet during pregnancy began to be suspected asa factor about 150 years ago, when the Irish potato famine was associated with a rise in the number. Similarly, a temporary increase was noted in Jamaica 11 to 18 months after Hurricane Gilbert devastated the island and its crops.4 The higher incidence of neural tube defects in England, Hungary, and parts of China have allowed for convincing studies of the preventive effects of folic acid. In England, Smithells5 first noted lower levels of serum folate in mothers of children with neural tube defects; in the 1980s studies showed that the recurrence risk could be lowered when mothers took 4 mg (4000 µg) of folic acid. Another study6 concluded that mothers who previously had a pregnancy affected by neural tube defects and who took 4 mg of folic acid daily during the time just before and after conception had 72 percent fewer babies with neural tube defects.
More recently, the preventive value of folic acid for women of childbearing age has been demonstrated. A study of Hun-garian mothers7 witha daily peri-conceptional intake of 800 µg of folic acid had significantly fewer neural tube defect first-occurrence births than expected. The China-U.S. Collaborative Project for Neural Tube Defect Prevention8 reported that 400 µg of daily peri-conceptional folic acid intake reduced the prevalence of neural tube defect pregnancies from 4.8 to 1.0 per 1000 in high-prevalence areas, and from 1.0 to 0.6 per 1000 in low prevalence areas of China. Consistency was important, with the greatest reduction occurring when the supplement was taken at least 80 percent of the time.
WHAT ARE THE CURRENT HEALTH PROMOTION EFFORTS?
Nationally, a major campaign to make folic acid a household name is supported by a partnership between public health groups and the March of Dimes. In Vermont, the March of Dimes has taken the lead.
In collaboration with the Vermont Department of Health, the March of Dimes has established an interagency council to advise and support health promotion efforts. Asa result, the VT Health Action Plan for 2000 includes folic acid intake among a set of actions keyed to the goals of the state health plan. The public education campaign to promote the use of folic acid has begun with a radio message from Health Commissioner Dr. Jan Carney,a letter to health care providers this spring, and patient education brochures and posters that are available through the March of Dimes, by calling 802-479-3265 or 800-696-9255 (in Vermont).
- Centers for Disease Control. Recommendations for the use of folic acid to reduce the number of cases of spina bifida and other neural tube defects. Morbidity and Mortality Weekly Report 1992;41(no. RR-14) or <http:// www.cdc.gov/epo/mmwr/preview/mmwrhtml/00019479.htm>.
- Iqbal MM. Prevention of neural tube defects by periconceptional use of folic acid. Pediatrics in Review. 2000;21:58-66.
- Vermont Triple Markers Prenatal Screening Program, Carol P. Walters, Ph.D., Director. “Occurrence” of neural tube defects in Vermont. Presentation to Vermont Folate Council, Burlington, Vermont, June 18, 1999.
- Watson Duff EM, Cooper ES. Neural tube defects in Jamaica following Hurricane Gilbert. American Journal of Public Health. 1994;84:473-476.
- Smithells RW, et al. Further experience of vitamin supplementation for prevention of neural-tube defect recurrences. Lancet 1983;1:1027-1031.
- Medical Research Council Vitamin Study Group. Prevention of neural tube defects: Results of the Medical Research Council vitamin study. Lancet. 1991;338:131-136.
- Czeizel AE, DudasI. Prevention of the first occurrence of neural-tube defects by periconceptional vitamin supplementation. New England Journal of Medicine. 1992;327:1832-1835.
- Berry RJ, et al. Prevention of neural-tube defects with folic acid in China. New England Journal of Medicine 1999;341:1485-1490.
New HIV Surveillance
Recent treatment advances, such as antiretroviral therapy, have slowed the progression of HIV infection to AIDS. As a result, people are living longer with HIV and the incidence of AIDS has declined. Therefore, epidemiologic data on AIDS alone no longer provides information about the extent of the HIV epidemic, or trends in HIV transmission. Today, HIV surveillance data combined with AIDS data provide a more realistic and useful estimate of resources needed for HIV prevention and treatment services than do AIDS data alone.1 The Centers for Disease Control and Prevention (CDC) and the Council of State and Territorial Epidemiologists recommend that all states conduct surveillance for HIV in addition to AIDS.2,3 Currently, 44 states include some form of HIV reporting asa part of their AIDS surveillance programs.
IMPLEMENTATION IN VERMONT
The Vermont Department of Health implemented non-name-based HIV surveillance on March 24, 2000, as a result of legislation passed by the Vermont legislature in 1999. Physicians, nurses, and laboratory directors are among those required to report all cases of HIV infection to the Department. Health care providers are responsible for filling out a Confidential Case Report form for each case, whether the case is initially reported by the health care provider or by a laboratory. Laboratory directors must report laboratory evidence of infection with HIV, but need not complete case report forms. In cases where the Department of Health does not receive a Confidential Case Report form within 30 days of receipt ofa positive test result froma laboratory, the HIV surveillance coordinator will follow up with the health care provider to ensure that the form is submitted.
Cases are reported bya unique identifier code, consisting of the third letter of the patient’s first name, the third letter of the patient’s last name, and the last four digits of the patient’s social security number. This code providesa mechanism for identifying duplicate case reports on individuals, while helping to ensure confidentiality. Names of persons infected with HIV are not reported to the Department of Health. Data from case reports are entered into a database. Data are released only in aggregate form. The Department of Health must meet the strict data security standards established by the CDC.
For more information about HIV surveillance in Vermont, or to request case report forms, please contact the HIV Surveillance Coordinator at (802) 863-7286. Anonymous testing for HIV, in which patients’ names are not collected and results are not reported, continues to be available at 17 sites throughout Vermont.
Who is Required to Report?
- Health Care Facilities
- Nurse Practitioners
- Physician Assistants
- Hospital Administrators
- Laboratory Directors
- School Health Officials
- Town Health Officers
- Managed Care Organizations
- Health Maintenance Organizations
- Centers for Disease Control and Prevention. Guidelines for national human immunodeficiency virus case surveillance, including monitoring for human immunodeficiency virus infection and acquired immunodeficiency syndrome. MMWR 1999; 48(No. RR-13):1-27.
- Centers for Disease Control and Prevention. Update: trends in AIDS incidence – United States, 1996. MMWR 1997;46:861-867.
- Council of State and Territorial Epidemiologists. CSTE position statement ID-4: national HIV surveillance – addition to the national public health surveillance system. Atlanta, GA: Council of State and Territorial Epidemiologists, 1997.
Vermont Cancer Registry Report Available
The Vermont Department of Health published Cancer in Vermont: A report of 1994-1996 cancer incidence data from the Vermont Cancer Registry. This report contains an analysis of the first three years of cancer incidence data compiled by the Vermont Cancer Registry. The report includes state age-adjusted incidence and mortality rates for 23 cancer site groupings (and all sites combined), as well as county rates for the four most commonly diagnosed cancers: breast, col-orectal, lung, and prostate. The report, which is intended for broad audiences, describes the disease of cancer and compares Vermont’s rates to the Nation. The four most commonly diagnosed cancers are explained in detail in site-specific sections.
The report shows that for most types of cancer, the incidence rates for both men and women are not statistically different from theU.S. rates. There area few exceptions: • For women, the age-adjusted incidence rates of colorectal, laryngeal and cervical cancer and multiple myeloma are statistically higher than national rates, and the rate of thyroid cancer is statistically lower.
• For men, the age-adjusted incidence rates of lung and laryngeal cancer are statistically higher than national rates, and the rates of stomach and prostate cancer are statistically lower.
A second report, Cancer Registration in Vermont, describes the elements of cancer registration that remain relatively constant every year, such as registry operations, confidentiality, regulations, and data methods. The publication contains technical appendices including State and Federal cancer registry legislation and site group definitions.
For a copy of either report, call 802-865-7749 or e-mail VTCancerRegistry@vdh.state.vt.us. The complete reports are also located on the Vermont Department of Health website <http://www.state.vt.us/health/pubs.htm>.
Vermont: Selected Reportable Diseases
January 1, 2000–March 31, 2000
- There is no five-year median for Cryptosporidiosis and Hepatitis C (Acute).
- If a reportable disease is not listed, no cases were confirmed as of March 31,2000.
Tick Testing for Lyme Disease Discontinued
Effective May 1, 2000, the Vermont Department of Health Laboratory will no longer accept ticks for identification and Borrelia burgdorferi Polymerase Chain Reaction (PCR) testing. This decision was made based on the low clinical value placed on the tick test results compared to the high cost of testing and the inadequacy of this asa surveillance tool for monitoring Lyme Disease in Vermont.
The Laboratory will continue to accept human serum specimens to be sent for analysis at the Centers for Disease Control and Prevention. For information on clinical specimen testing requirements, please call the Microbiology Program at the Vermont Department of Health Laboratory, 802-863-7629 or toll-free in Vermont 1-800-660-9997, extension 7629.
Improved Laboratory Services for Tuberculosis
The Vermont Department of Health Laboratory is committed to the implementation of all laboratory services recommended by the Advisory Council for the Elimination of Tuberculosis (ACET). As a result of that commitment, the laboratory has recently added the Amplified Mycobacterium Tuberculosis Direct (MTD) Test (Gen-Probe) to the list of offered services. The MTD test isa target-amplified nucleic acid probe test for the detection ofM. tuberculosis complex ribosomal ribonucleic acid (rRNA) in human specimens. M. tuberculosis complex includes M. tuberculosis,M. bovis,M. bovis BCG, M. africanum, and M. microti, with M. tuberculosis being the most frequently isolated.
The MTD test is used as an adjunctive test for evaluating acid-fast bacilli smear positive sediments prepared from sputa, bronchial lavages, bronchial aspirates or tracheal aspirates collected from untreated patients suspected of being infected with M. tuberculosis. Patients who have received no antitu-berculous therapy, less than seven days of such therapy, or have not received such therapy within the last 12 months may be tested by this method.
The MTD test can usually be performed within 24 hours of receipt and therefore provides a rapid result. For completeness of testing, the MTD test is always performed in conjunction with mycobacterial culture. Culture may take up to six to eight weeks for final results.
AFB positive smears may be MTD test negative and M. tuberculosis complex culture positive due to MTD test interference by specimen inhibitors or the presence of low numbers of the M. tuberculosis complex organism in the presence of large numbers of Mycobacterium other than tuberculosis (MOTT). Blood in specimens may cause false positive MTD results; therefore, specimens that are grossly bloody should not be tested with the MTD test.
Tuberculosis testing continues to bea public health priority service and as such is available without charge to all Ver-mont health care providers and patients. Specimens must be collected in the Vermont Department of Health #6 kit (for Mycobacterial culture) and stored at refrigerated temperature (2° to 8° C) until transported to the laboratory. Ideally, specimens should be shipped to arrive at the laboratory within 24 hours of collection.
Please contact the Vermont Department of Health Laboratory Microbiology Program at (800)-660-9997 x7629 or (802) 863-7629 with questions or comments about the MTD test or specimen collection.
REPORT DISEASE : VERMONT TOLL-FREE
1-800-640-4374 OR 1-802-863-7240
Vermont Department of Health
Division of Health Surveillance P.O. Box 70 Burlington, VT 05402-0070
Agency of Human Services
Jan K. Carney, MD, MPH
THIS BULLETIN IS PRODUCED BY THE EPIDEMIOLOGY PROGRAM STAFF.