July 29, 2009- England and Australia- Pap smears in the under-25s has prompted calls from some experts for a review of Australia's cervical cancer screening program.
But other experts say it is unwise to change the system yet and all urge women to keep being screened.
The UK study, reported online today in the British Medical Journal, shows cervical cytology screening in women aged between 20 and 24 has little or no impact on rates of invasive cervical cancer up to age 30.
The study analysed data from 4,012 women with cervical cancer and nearly 8,000 without.
The researchers found that smears were far less effective at preventing cancer in 20- to 24-year-olds than in older women, who saw screening lead to substantial drops in death and incidence of between 60 percent to 80 percent.
Cancer epidemiology professor Peter Sasieni from Queen Mary University of London says, "These data should help policy-makers balance the impact of screening on cancer rates against its harms, such as overtreatment of lesions with little invasive potential."
An accompanying editorial says screening leads to many detected abnormalities in younger women with only a fraction being progressive, but this important fraction which will progress to invasive cancer in the next five years may be missed by screening.
But researchers say there is some uncertainty regarding screening impact on advanced tumors in women under the age of 30.
Despite two other studies backing their findings, one found no evidence of screening being less effective in young women.
Controversial change
English authorities controversially changed their screening program in 2003, inviting women to have their first Pap smear at age 25 instead of 20 to 24. Australia's policy advises starting screening at 20, or two years after starting sexual activity, whichever is later.
Victorian Cytology Service director, Associate Professor Marion Saville, says the study's finding adds weight to the idea that screening women under 25 may not be useful and expose many to unnecessary investigations and treatments.
"In the very small number of women destined to get cervical cancer at an early age, this study suggests screening does not prevent development of these cancers," she says.
Professor Saville also believes the study's publication is timely.
"The Australian government is planning to review screening policy in the next few years, but it is a complex task which will take time as many different aspects need to be considered," she says.
"While the government considers all the evidence, women should understand that at the moment the best protection against cervical cancer is to have Pap smears regularly."
Cost savings
Westmead Hospital director of gynecological oncology, Dr Gerry Wain, says there is great potential for safely changing the system and saving money.
"Screening has no benefit in this age group and there should be a major review of the way we conduct screening in Australia, especially given the impact of the cervical cancer vaccine on human papilloma virus (HPV) prevalence rates," he says.
"Government bureaucrats have announced their intention to have a review and it should involve time of onset, interval, frequency and methods."
Dr Wain says Australia's high HPV vaccination rate will dramatically reduce the incidence and prevalence of the virus in younger groups.
Call to keep status quo
The vaccine's inventor, University of Queensland Professor Ian Frazer, says vaccination should have no impact on design of the screening program in the short to medium term, as most at-risk women have not been vaccinated or were vaccinated when they had the virus.
"Altering the current Australian screening program at the moment is probably unwise as it will be our best quality check on the efficacy of the vaccine program," he says.
"Changes introduced along with vaccination might send a message to vaccinated women that they don't need to be screened, which could have serious consequences."
Cancer Council of Australia CEO Professor Ian Olver says until there is a review, the program should stay as it is and women should keep being screened.
"Our Pap smear program has reduced annual deaths to the 200s instead of thousands...changes might disrupt the most successful screening program there has ever been," he says.
Professor Olver believes the introduction of the HPV vaccine has provided an "interesting transition," which will prompt future planning.
"We need to start planning what to do, so we need a review to include whether screening should be two or three yearly, when it should start and methods."
Between 2006 and 2008, more than 3.5 million women had a Pap smear test, according to the Australian Institute of Health and Welfare. In 2005, cervical cancer claimed 216 lives, or less than two in 100,000 women, with approximately one in 1,000,000 aged between 20 and 24.
Link to article: http://www.nccc-online.org/view_article.php?news_id=1288