Tuesday, October 29, 2013

Why don't physicians discuss cancer screening harms?

- Kenny Lin, MD, MPH

Last month, I attended a conference that included an exercise where attendees were asked how many patients they thought it was acceptable to diagnose and treat needlessly (or "overtreat") in order to prevent one death from cancer. We stood at various points along a wall that represented different thresholds: at one end, 100 persons overtreated for every 1 life saved; at the other, 1 person overtreated for every 1 life saved. Not surprisingly, attendees held a wide range of opinions (I stood somewhere in the middle), but the exercise illustrated the tradeoff inherent in effective screening tests for breast, colorectal, and cervical cancer: for every person who benefits from screening, others will be harmed. This fact has led many physicians to advocate that shared decision-making be used more widely to integrate patients' preferences and values with the decision to accept or decline a screening test.

How often do physicians take the time to explain the harms of cancer screening to their patients? A research letter published in JAMA Internal Medicine explored this question in an online survey of 317 U.S. adults between 50 and 69 years of age. 83 percent of participants had attended at least 1 routine cancer screening; 27 percent had undergone 3 or more. However, less than 10 percent of participants had ever been informed by their physicians of the risk that the screening test(s) could lead to overdiagnosis and overtreatment. The few physicians who did attempt to quantify this risk generally provided information that was inconsistent with the medical literature.

If the results of this survey are representative of the practices of U.S. family physicians, then more than 90 percent of us aren't telling patients that there are downsides to undergoing routine mammograms, colonoscopies, and Pap smears. Why not? Is it because we aren't familiar enough with the data to accurately describe these harms? Or is it because we fear that patients who receive information about cancer screening harms will choose to decline these tests?

Monday, October 21, 2013

FIT colorectal screening: is annual testing necessary?

- Jennifer Middleton, MD, MPH

One of the POEMs in last week's American Family Physician discussed a recent study from the Netherlands regarding fecal immunochemical testing (FIT) for colorectal cancer screening; the researchers studied the prevalence of screening, rate of positive screening results, and rate of identified colorectal neoplasia.  They found that screening annually did not increase the yield of new colorectal cancer cases compared with screening every 2 to 3 years.

Having a viable alternative to colonoscopy is vitally important to ensuring that our patients get colorectal cancer screening.  Colorectal cancer is the fourth most common form of cancer in the U.S., but at least 1/3 of U.S. adults aged 50-75 are not getting adequate screening.  A survey by the Colon Cancer Alliance found that fear of the bowel prep and procedure keeps many adults from getting a screening colonoscopy.  I have several patients who appreciate having the option of a less invasive screening tool.

At first, our only alternative to offer was the fecal occult blood test (FOBT), but then FIT came onto the scene with several advantages. Certain fruits and vegetables, along with red meat, can cause false positives with FOBT, and vitamin C supplementation can cause false negatives.  FIT, by looking at globin instead of heme, eliminates the effect from these heme-based test confounders.

I still remember convincing our practice to switch from FOBT to FIT after learning these points.  But we experienced an unexpected result - fewer of our patients were returning the FIT than the FOBT.  It turned out that the FIT kit instructions were difficult for many of our patients to follow. Take a look and compare for yourselves:

FIT: http://www.insuretest.com/resources/InSureFIT-Patient_Instructions.pdf
FOBT: http://health.gov.on.ca/en/public/programs/coloncancercheck/docs/fobt/English_FOBT_instructions.pdf

With FOBT, patients just have to smear some stool onto a card.  But, with FIT, patients have to use a paintbrush over the surface of the stool, transferring this water instead of stool to the card, all the while making sure that no toilet paper gets into the toilet bowl.  So, which is worse: dietary restrictions with FOBT, or more complicated instructions with FIT? Perhaps the answer for your patients is different than it was for ours.

What I appreciated about the article featured in AFP, though, was the change in screening interval.  The researchers found that more patients participated in the biannual and triannual screening than they did if it was annual; screening less often resulted in more people getting screened.  If other researchers can validate this point on a larger scale, this expanded screening interval may tip the balance in favor of FIT once and for all. For now, the American College of Physicians, as reviewed in AFP last year, advises that physicians may offer average risk patients FIT, FOBT, flexible sigmoidoscopy, or colonoscopy.  This article, and several more, are available in the AFP By Topic for colorectal cancer.

So, how are you tackling colorectal cancer screening in your office?

Tuesday, October 15, 2013

Updates in HIV screening and prevention

- Kenny Lin, MD, MPH

Although the introduction of highly active antiretroviral therapy for HIV has led to substantial declines in AIDS diagnoses and deaths from their peaks in the mid-1990s, an estimated 50,000 persons in the U.S. are infected with HIV each year, and more than 236,000 persons living with HIV are unaware of their diagnoses, according to the Centers for Disease Control and Prevention. Noting that many HIV infections occur in persons without identifiable risk factors, earlier this year the U.S. Preventive Services Task Force recommended that clinicians routinely screen all adolescents and adults ages 15 to 65 years (the American Academy of Family Physicians recommends starting routine screening at age 18).

Identifying infected persons through screening allows for earlier initiation of effective therapy, but there is limited evidence that the diagnosis affects sexual and injection drug use behaviors that could prevent transmission of HIV. Recently, several randomized trials of antiretroviral preexposure prophylaxis in high-risk populations have demonstrated reductions in new HIV infections; a Cochrane review concluded that 56 persons needed to receive prophylaxis to prevent one new infection.

The October 15th issue of AFP includes a STEPS drug review of emtricitabine/tenofovir (Truvada) for HIV preexposure prophylaxis. Although this drug is effective and generally well tolerated in persons with normal renal function, it comes at a steep price: more than $1200 for a one-month supply. Whether it makes sense to prescribe an expensive and potentially toxic drug to uninfected persons who might acquire HIV due to high-risk behaviors such as injection drug use remains a topic of debate. The CDC and other U.S. public health agencies plan to publish comprehensive guidance on the use of antiretroviral preexposure prophylaxis within the next year.

How have the expanded HIV screening recommendations and the availability of preexposure prophylaxis regimens affected your practice?

Monday, October 7, 2013

Meniscal tears in arthritic knees: refer to physical therapy first

- Jennifer Middleton, MD, MPH

Meniscal injuries in arthritic knees challenge me. While some patients are more than willing to start with physical therapy (PT), some like the idea of a "quick" surgical fix over the perceived drudgery of a course of PT.  I struggle, too, at times, trying to judge who and when to refer to orthopedics, knowing full well that the patients I refer are likely to end up undergoing arthroscopy.

Kirkley et al showed in 2008 that arthroscopy for osteoarthritis makes no difference in pain or mobility scores. The AFP By Topic on Arthritis and Joint Pain includes this 2011 AFP article on knee osteoarthritis treatment that goes into more detail regarding the lack of evidence showing benefit following knee arthroscopy.  The jury is still out regarding whether surgery is necessary for meniscal tears even in patients without arthritis; a 2000 Cochrane review found insufficient evidence to conclude that surgery or PT is superior to the other.  Until recently, though, no one had specifically studied if arthroscopy benefits adults with osteoarthritis who suffer a meniscal tear.

A study published this past spring in the New England Journal of Medicine, which American Family Physician will be reviewing in its upcoming issue, may give us an answer.  The authors found no difference in pain and mobility after 6 and 12 months among patients who had had arthoscopic surgery followed by PT versus patients who only had PT.  In this trial, researchers randomized adults with painful meniscal tears (verified by MRI) who also had radiologic evidence of osteoarthritis to either surgery followed by PT or just PT alone. (Interestingly, patients did not have to have had symptomatic osteoarthritis prior to their meniscal tear; the appearance of arthritic changes on MRI alone got them enrolled in the study.)  The researchers then followed participants with previously validated pain and knee function questionnaires 6 and 12 months after their therapy or surgery. They found no statistically significant difference in these scores between groups.

Although the authors state that they conducted an intention-to-treat analysis in the article's abstract, in the methods section they qualify this as having been a "modified intention-to-treat approach in which patients who did not withdraw from the study were evaluated in the group to which they were randomly assigned."  Participants in the PT arm did have the opportunity to cross over to the surgical arm if they failed therapy, and 51 of the participants initially assigned to the PT group did so.  The authors appropriately included these patients in their intention-to-treat analysis but chose not to include the participants who dropped out before the 12 month follow-up.

31 of the study's inital 351 participants dropped out, and not including them in the statistical analysis could have skewed the results.  It's possible, for example, that the patients who dropped out of the PT arm went somewhere else for surgery and did better than they otherwise would have.  I applaud the authors for their transparency regarding this decision but remain unsure why they chose not to include the drop-outs in their final analysis.

That small misgiving aside, their findings still make intuitive sense given what we already know about knee arthroscopy.  This study's findings will make me more likely to refer patients with suspected meniscal tears to physical therapy first, even if they already have osteoarthritis.

Will this study change your management of meniscal tears in your older adults with known or suspected knee arthritis?