Editorials - March 15, 2000 - American Academy of Family Physicians

Editorials

Overcoming the Barriers to Change: Screening for Colorectal Cancer

STEVEN H. WOOLF, M.D., M.P.H.
Medical College of Virginia
Virginia Commonwealth University
Fairfax, Virginia

See article in this issue.

In this issue of American Family Physician, Rudy and Zdon¹ review the benefits of early detection of colorectal cancer. Citing a previously published model,² they estimate that screening 100,000 persons with fecal occult blood testing, sigmoidoscopy, barium enema or colonoscopy could prevent from 958 to 1,843 deaths, depending on the tests that are used. Given these benefits, most guidelines now recommend routine screening for colorectal cancer in all persons 50 years of age and older.

Patients, however, are less than enthusiastic about colorectal cancer screening. According to a 1997 survey,³ only 20 percent of Americans 50 years of age or older are up-to-date on fecal occult blood testing, and only 30 percent are current on sigmoidoscopy screening. In contrast, 69 percent of women 40 years of age and older have had a recent mammogram.⁴

Even for physicians, colorectal cancer screening is not high on the list of clinical priorities. The fact that physicians might not always offer an intervention known to save lives is nothing new. The same is true for use of beta blockers and aspirin after an acute myocardial infarction, warfarin for atrial fibrillation, angiotensin-converting enzyme inhibitors for congestive heart failure and other evidence-based measures for various conditions.⁵

Why would physicians and patients not pursue treatments that are known to improve health? The answer is obvious: knowledge alone is not enough to change behavior. Behavioral change evolves from four steps: (1) knowledge, (2) acceptance, (3) ability and (4) reinforcement. Knowledge is the awareness of new evidence or practice guidelines, and acceptance is agreement that the proposed policy represents good care. Ability involves having the time and resources to implement change, and reinforcement entails the use of reminder systems and other measures that maintain the practice over time.⁵ By itself, providing knowledge (e.g., publishing a review article or guideline) does little to change practice patterns.⁶

This framework helps to explain clinicians' disaffection with colorectal cancer screening. The first barrier is lack of knowledge. Many physicians are unfamiliar with the evidence that screening reduces mortality. Until recent trials demonstrated otherwise,⁷ the conventional wisdom was that colorectal cancer screening had no proven benefit. Furthermore, physicians may not know the current protocols for screening. Many assume that guaiac testing in the office, performed on the glove used in a rectal examination, constitutes fecal occult blood testing. (What lowered mortality in clinical trials was the collection of six specimens at home--two samples from three consecutive stools.⁷) Physicians also may know little about the effects of rehydrating fecal occult blood test cards (better sensitivity but decreased specificity, and, thus, an increase in the probability of false-positive results and work-ups). Finally, physicians may not know which types of polyps are premalignant or, having detected polyps on endoscopy or barium enema, which sizes require biopsy.

The next barrier is attitudinal. Physicians can know the facts about colorectal cancer screening but remain uneager to act. For many years, colorectal cancer screening was the focus of conflicting guidelines and controversy. Not until 1996 did the U.S. Preventive Services Task Force abandon the position that evidence was insufficient to make a recommendation. It is not well known that this group (and most others) now enthusiastically recommends colorectal cancer screening.⁸ Given this ambiguity and the dismal compliance rates of patients with regard to colorectal screening, many physicians give priority to other preventive services (e.g., tobacco counseling, blood pressure and lipid control). Some physicians who know the data are not impressed by the magnitude of benefit.⁹ For example, by one calculation, 1,374 patients must undergo fecal occult blood testing for five years to prevent one death from colorectal cancer.¹⁰

There can also be barriers to the ability to perform effective colorectal cancer screening. Even enthusiastic physicians cannot screen patients if they lack time, patient cooperation, office help, ease of referral to gastroenterologists or insurance coverage. They cannot perform endoscopy skillfully without training and volume. Finally, reinforcement is critical. Screening cannot be effective if measures are not in place to remind physicians when patients are due for screening or if physicians forget to act on abnormal results.

The same framework explains patient behavior. Knowledge is the first problem. Some Americans have never heard of colorectal cancer, let alone the screening measures for this malignancy. Although breast cancer claims 11,000 fewer lives each year,¹¹ it is perceived as being more deadly than colorectal cancer. Attitudes pose an even bigger barrier for patients. They find fecal occult blood testing distasteful, and they anticipate discomfort and embarrassment with endoscopy or barium enema. Those who want to be screened may lack ability. Reading and language barriers can make instructions useless. Older patients with poor vision or manual dexterity cannot collect stool specimens. Limited insurance and lack of access to physicians can create further impediments. Finally, patients need reinforcement. Few patients remember, five years hence, that it is time for another sigmoidoscopy. Reminders from the physician who performed the test help little if the patient has moved or, as occurs frequently in managed care, has acquired a new physician.

The secret to changing behavior lies in recognizing the barriers that apply and crafting smart solutions to address them.^5,6 In promoting colorectal cancer screening, it is worth remembering that no single test is ideal. The data cited by Rudy and Zdon,¹ which suggest that colonoscopy and barium enema save more lives than fecal occult blood testing or sigmoidoscopy, was derived from mathematical models.² The only direct trial evidence that screening reduces mortality involves fecal occult blood testing.⁷ The evidence for sigmoidoscopy comes from case-control studies.¹² Given the prevalence of premalignant polyps and cancers in the proximal colon, it seems logical that whole-bowel examinations would save more lives, but this has not been proved. Furthermore, each screening test has a different mix of potential harms, discomforts and costs that influence its acceptability.

The "best" choice depends on patient preference. One group of investigators¹³ found different patient preferences for colonoscopy (38 percent), fecal occult blood testing (31 percent), barium enema (14 percent) and sigmoidoscopy (13 percent). Other investigators¹⁴ found that preferences for fecal occult blood testing and sigmoidoscopy changed as patients received more information. When patients were given general descriptions of the disease and screening tests, their order of preferences was fecal occult blood testing (45 percent), both tests (38 percent) and sigmoidoscopy alone (13 percent). However, when they learned about test accuracies, more patients preferred both tests (47 percent), and fewer wanted fecal occult blood testing alone (36 percent). When patients were told about out-of-pocket costs, preferences for fecal occult blood testing alone rose to 53 percent, and requests for both tests fell to 31 percent.

Given these variations, most guidelines urge physicians to discuss the options with patients before settling on the ideal screening protocol.¹⁵ Offering such counseling in busy practices is not easy, as noted in a previous AFP editorial,¹⁶ and deserves greater research attention.

Steven H. Woolf, M.D., M.P.H., is professor of family medicine in the Department of Family Practice at the Medical College of VirginiaVirginia Commonwealth University, Fairfax, Va.

Address correspondence to Steven H. Woolf, M.D., M.P.H., Department of Family Practice, Medical College of VirginiaVirginia Commonwealth University, 3712 Charles Stewart Dr., Fairfax, VA 22033.

REFERENCES

1. Rudy DR, Zdon MJ. Update on colon cancer. Am Fam Physician 2000;61:1759-68.

2. Winawer SJ, Fletcher RH, Miller L, Godlee F, Stolar MH, Mulrow CD, et al. Colorectal cancer screening: clinical guidelines and rationale. Gastroenterology 1997;112:594-642 [Published errata appear in Gastroenterology 1997;112:1060 and 1998;114: 635].

3. Screening for colorectal cancer--United States, 1997. MMWR Morb Mortal Wkly Rep 1999; 48:116-21.

4. Self-reported use of mammography and insurance status among women aged >= 40 yearsUnited States, 1991-1992 and 1996-1997. MMWR Morb Mortal Wkly Rep 1998;47:825-30.

5. Woolf SH. Changing physician practice behavior: the merits of a diagnostic approach. J Fam Pract 2000;49:126-9.

6. Bero LA, Grilli R, Grimshaw JM, Harvey E, Oxman AD, Thomson MA, et al. Closing the gap between research and practice: an overview of systematic reviews of interventions to promote the implementation of research findings. BMJ 1998;317:465-8.

7. Towler B, Irwig L, Glasziou P, Kewenter J, Weller D, Silagy C. A systematic review of the effects of screening for colorectal cancer using the faecal occult blood test, hemoccult. BMJ 1998;317:559-65.

8. U.S. Preventive Services Task Force. Guide to clinical preventive services. 2d ed. Baltimore: Williams & Wilkins, 1996:89-103.

9. Budenholzer B. Benefits of screening for colorectal cancer. Am Fam Physician 1998;57:947-8,950.

10. Rembold CM. Number needed to screen: development of a statistic for disease screening. BMJ 1998; 317:307-12.

11. Landis SH, Murray T, Bolden S, Wingo PA. Cancer statistics, 1998. CA Cancer J Clin 1998;48:6-29 [Published errata appear in CA Cancer J Clin 1998;48:192 and 1998;48:329].

12. Selby JV, Friedman GD, Quesenberry CP Jr, Weiss NS. A case-control study of screening sigmoidoscopy and mortality from colorectal cancer. N Engl J Med 1992;326:653-7.

13. Leard LE, Savides TJ, Ganiats TG. Patient preferences for colorectal cancer screening. J Fam Pract 1997;45:211-8.

14. Pignone M, Bucholtz D, Harris R. Patient preferences for colon cancer screening. J Gen Intern Med 1999;14:432-7.

15. Woolf SH. Shared decision-making: the case for letting patients decide which choice is best [Editorial]. J Fam Pract 1997;45:205-8.

16. Ganiats TG, Young HF. Screening options for colorectal cancer [Editorial]. Am Fam Physician 1999; 59:2979-80.

Avoiding Drug Interactions

JOYCE GENERALI, M.S., R.PH.
University of Kansas Medical Center
Kansas City, Kansas

See article in this issue.

In this issue of American Family Physician, Ament and colleagues¹ highlight several important drug interactions and also raise an ongoing health care concern: How can morbidity and mortality from drug interactions be reduced?

A recent study² showed that although drug interactions are responsible for only 3.8 percent of emergency department visits, these patients usually have to be admitted to the hospital. Another study³ indicated that preventable drug interactions are responsible for approximately one third of all adverse events in hospitalized patients and account for one half of the costs attributed to adverse events.

Preventing undesirable drug interactions requires that family physicians make full use of available resources and keep current with recent changes in drug safety. Unfortunately, the safety profile of a drug (adverse reactions and drug interactions) is not static and can change as the drug is prescribed more frequently in varied patient populations.

In the past two and one half years, an unprecedented number of drugs have been withdrawn from the U.S. market for safety reasons discovered through postmarketing surveillance. These drugs include fenfluramine (Pondimin), dexfenfluramine (Redux), terfenadine (Seldane), bromfenac (Duract), astemizole (Hismanal), mibefradil (Posicor), grepafloxacin (Raxar) and, most recently, the rotavirus vaccine (Rotashield). Serious drug interactions were a factor in the withdrawal of at least three of these drugs (terfenadine, astemizole and mibefradil).

In addition, approximately one fifth of all safety notifications posted on the Web site of the U.S. Food and Drug Administration (FDA) in 1999 concerned new safety warnings about drug interactions.⁴ Included were interactions between celecoxib (Celebrex) and warfarin (Coumadin); methotrexate (Rheumatrex) and radiotherapy; pimozide (Orap) and cytochrome P450-3A (CYP3A) inhibitors; cisapride (Propulsid) and grapefruit juice; and nevirapine (Viramune) and methadone.

Because the FDA approves approximately 25 new molecular entities (drugs not previously marketed in the United States) each year, keeping abreast of new drug interactions is difficult. The article by Ament and colleagues¹ lists a number of resources that are valuable in screening for drug interactions. At least one of these references should be available at every practice site. However, it is important to note that drug information references are merely tools and do not replace basic knowledge of pharmacology, clinical judgment and sound problem-solving skills.

In using any drug information resource, family physicians should keep a number of factors in mind. Knowing the capabilities and limitations of a particular resource is as important as knowing how to use it. It is important to select a resource that is updated several times a year to maximize the chance that the information in the resource is current. A good drug information resource provides information on the severity of interactions, their potential clinical significance, management suggestions and references if further information is desired.

Even with updates, information in any drug interaction resource is typically six months behind the published literature. Thus, the resource may not contain data on newly released products, information from recent FDA announcements or data released by pharmaceutical companies in the form of letters to health professionals.

It is important to access alternative sources when prescribing newly marketed drugs (less than one year old). A significant consideration is interactions with alternative or herbal medicines, in that the popularity of these therapies has increased the potential for previously unknown interactions.

In addition to the drug interaction resources mentioned by Ament and colleagues,¹ journals, local pharmacists, drug information centers and the Internet are valuable avenues for keeping current. Pharmacists and drug information centers often use computerized drug interaction databases. These databases are efficient screening tools for a large number of drug interactions.

The FDA Web site for the year 2000 contains information on recent labeling changes related to safety.⁵ The information is organized by the brand and generic names of drugs. The Web site also includes summaries of letters to health care professionals from pharmaceutical companies, and other important safety notifications regarding drugs, biologics, dietary supplements and medical devices.

Family physicians who regularly access electronic mail (e-mail) can keep abreast of newly published or about-to-be-published information on drug interactions by receiving tables of contents from electronic journals. Most online journals currently offer this service free of charge to subscribers and nonsubscribers. Some journals will e-mail only the specific topics of interest selected by the reader, thereby minimizing unnecessary correspondence.

Selecting medication regimens that optimize therapeutic benefits, minimize side effects and avoid detrimental drug interactions remains an essential component of patient care. Although keeping up with new drug safety information can be time-consuming, accessing various drug information resources may increase awareness and prevent drug interactions.

Joyce Generali, M.S., R.Ph., is clinical associate professor and director of the Drug Information Center at the University of Kansas Medical Center, Kansas City, Kan.

Address correspondence to Joyce Generali, M.S., R.Ph., Department of Pharmacy, Drug Information Center, University of Kansas Medical Center, 3901 Rainbow Blvd., Kansas City, KS 66160-7231; e-mail address: jgeneral@kumc.edu.

REFERENCES

1. Ament PW, Bertolino JG, Liszewski JL. Clinically significant drug interactions. Am Fam Physician 2000;61:1745-54.

2. Raschetti R, Morgutti M, Menniti-Ippolito F, Belisari A, Rossignoli A, Linghini P, et al. Suspected adverse drug events requiring emergency department visits or hospital admissions. Eur J Clin Pharmacol 1999; 54:959-63.

3. Bates DW, Spell N, Cullen DJ, Burdick E, Laird N, Petersen LA, et al. The costs of adverse drug events in hospitalized patients. Adverse Drug Events Prevention Study Group. JAMA 1997;277:307-11.

4. New safety information summaries. FDA Web site 1999. Retrieved December 27, 1999 from the World Wide Web: http://www.fda.gov/medwatch/safety/1999/safety99.htm.

5. New safety information summaries. FDA Web site 2000. Retrieved January 11, 2000 from the World Wide Web: http://www.fda.gov/medwatch/safety/2000/safety00.htm.

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