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27-05-2012 | Article

The week in review: May 20‑26, 2012

MedWire News: Among this week's featured stories are a controversial recommendation regarding prostate cancer screening, new guidelines for lung and colorectal cancer screening, a stark portrait of rising cardiovascular risks in US youth, and mixed signals on reducing hypertension through treatment of sleep apnea.

Thumbs down on PSA screening for prostate cancer

In a move that variously sparked praise and condemnation, the US Preventive Services Task Force (USPSTF) issued clinical guidelines recommending against the routine use of prostate-specific antigen (PSA)-based screening for prostate cancer.

The task force members reviewed data from two large trials: the US Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial and the European Randomized Study of Screening for Prostate Cancer (ERSPC). PSA screening did not result in a reduction in prostate cancer mortality in the PLCO trial, and in the European trial the reduction was small, at approximately one death per 1000 men screened in a subgroup of men aged 55 to 69 years.

Otis Brawley, chief medical officer and executive vice president of the American Cancer Society, supports the recommendation.

Brawley and the USPSTF maintain that the potential for harm from detecting and treating cancers that otherwise may have been inconsequential appear to outweigh any potential benefit from the screening.

However, William Catalona (Urological Research Foundation, St Louis, Missouri) and other leading prostate cancer surgeons and physicians point out that the USPSTF panel does not include urologists or cancer specialists. They contend that "the USPSTF has underestimated the benefits and overestimated the harms of prostate cancer screening. Therefore, we disagree with the USPSTF's recommendation."

They question the methodology of studies the USPSTF relied most heavily on, and warn that the blanket recommendation against screening "could result in delayed diagnosis of curable cancer in young men who may then present with advanced disease, illness, and death."

American Urological Association President Sushil Lacy meanwhile expressed "outrage," arguing that the recommendations are too broad, and do not take into account the possibility that certain subgroups of men might benefit from PSA screening.

"It is inappropriate and irresponsible to issue a blanket statement against PSA testing, particularly for at-risk populations, such as African‑American men. Men who are in good health and have more than a 10‑15 year life expectancy should have the choice to be tested and not discouraged from doing so," Lacy says.

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CT or not CT for lung cancer screening?

A less controversial recommendation comes from the American College of Chest Physicians (ACCP) and the American Society for Clinical Oncology (ASCO), who issued new joint guidelines regarding the use of computed tomography in lung cancer screening.

The guidelines recommend annual screening with low-dose CT for both current and former smokers from the ages of 55 to 74 years who have smoked for 30 pack-years (cigarette packs smoked per day multiplied by years of smoking) or more and who either continue to smoke or have quit within the last 15 years.

The guidelines recommend against the routine use of CT screening in smokers with fewer than 30 pack years or are either younger than 55 years older than 74, or those who kicked the habit more than 15 years ago. They also note that "in individuals with severe comorbidities that would preclude potentially curative treatment, limit life expectancy, or both, we suggest that CT screening should not be performed."

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Flexible sigmoidoscopy saves lives

Also on the cancer screening front, a new study of data from the PLCO shows that routine flexible sigmoidoscopy screening is associated with a significant reduction in overall colorectal cancer (CRC) incidence and mortality.

Flexible sigmoidoscopy was associated with a 21% reduction in CRC incidence among patients randomized to be routinely screened with the technique compared with those assigned to usual care in the PLCO Screening trial, reported Robert Schoen (University of Pittsburgh, Pennsylvania) and co-authors in the New England Journal of Medicine.

The routine sigmoidoscopy approach was also associated with a 26% reduction in overall cancer mortality compared with usual care, and with a 50% lower incidence of deaths from cancers arising in the distal colon. There was no significant difference in deaths from cancers in the proximal colon, however.

After a median 11.9 years of follow-up, there were 1012 cases of CRC in the screening group, yielding an incidence of 11.9 cases per 10,000 person‑years. In comparison, there were 1287 cases among the 77,445 participants assigned to usual care, for an incidence of 15.2 cases per 10,000 person‑years (relative risk [RR]=0.79).

Flexible sigmoidoscopy was associated with a lower relative risk for both distal cancers (RR= 0.71) and proximal CRC (RR=0.86).

The incidence of death from CRC was 2.9 per 10,000 person‑years in the sigmoidoscopy group, compared with 3.9 per 10,000 in the usual care group (RR=0.74). Deaths from distal CRC were 50% lower among patients who underwent sigmoidoscopy (RR=0.50), but there was no between-group difference in mortality from proximal CRC (RR=0.97).

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Here's looking at more of you, kid

US adolescents are at significant risk for cardiovascular disease (CVD) from high blood pressure, diabetes, and other risk factors, and the risk is especially high among overweight and obese youth, according to a new report based on national surveillance data.

Analysis of 3383 12‑19-year-old participants in the National Health and Nutrition Examination Survey (NHANES) from 1999 through 2008 shows that 14% had prehypertension or hypertension, 22% had low-density lipoprotein (LDL) cholesterol in the borderline high or high range, and 15% had prediabetes or diabetes, write Ashleigh May (Centers for Disease Control and Prevention) and colleagues.

In addition, the prevalence of LDL cholesterol levels in the borderline‑high range was 22%, and 6% had low levels of high-density lipoprotein cholesterol.

About half (49%) of overweight teens and three-fifths (61%) of those who were obese had one or more risk factors for CVD in addition to the elevated risk posed by their excess weight, May et al report in an article released early online in Pediatrics, the official journal of the American Academy of Pediatrics.

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CPAP for high BP? Let me sleep on it

Two new studies appearing in JAMA provide conflicting data on the benefits of continuous positive airway pressure (CPAP) for preventing or controlling hypertension in patients with obstructive sleep apnea (OSA).

In the first, Ferran Barbé (Institut de Recerca Biomedica, Lleida, Spain), and co-authors in the Spanish Sleep and Breathing Network randomly assigned 725 consecutive patients with OSA but no daytime sleepiness to CPAP or no active intervention.

The incidence density rate for either hypertension or cardiovascular events, the primary endpoint, among patients in the CPAP group was no different from that among controls, at 9.20 versus 11.02 per 100 person-years.

"This study suggests that in patients with OSA and without daytime sleepiness, the prescription of CPAP compared with usual care did not result in a statistically significant reduction in the incidence of hypertension or cardiovascular events," Barbé et al write.

In the second study, researchers from the USA and Spain led by José Marin (Hospital Universitario Miguel Servet, Zaragoza, Spain) looked at 1889 patients without hypertension who were referred to a sleep center for nocturnal polysomnography from 1994 through 2000, and followed them for a median of 12.2 years.

Among patients with OSA treated with CPAP, the crude incidence of hypertension per 100 person‑years was 3.06, compared with 5.12 for patients with OSA who were prescribed CPAP but were nonadherent, 5.84 in patients with OSA who declined CPAP, 3.34 for patients with OSA ineligible for CPAP, and 2.19 for controls (patients without OSA).

In multivariate models adjusted for confounding factors including age, gender, baseline systolic and diastolic blood pressure, lipids, drugs, change in body mass index censored for time, and other factors, they found that the risk for hypertension was significantly greater than for controls among patients with OSA who declined (hazard ratio [HR]=1.96), were ineligible for (HR=1.33), or were nonadherent to CPAP (HR=1.78). By contrast, the risk was lower than for controls among CPAP-treated OSA patients (HR=0.71).

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By Neil Osterweil