Changes to cervical cancer screening
Tuesday, 25 October, 2016
The Australian National Cervical Screening Program (NCSP) will transition in 2017 from cytology-based screening every two years, starting from age 18–20 years, to HPV-based screening every 5 years, starting from age 25.
Cancer of the cervix is a malignancy, resistant to treatment, but fortunately preventable when detected in the precancerous stage.
For many years Australia has been a world leader in cervical cancer screening and the result has been very low rates of invasive cervical cancer by international standards. But from next year cervical cancer screening will undergo a radical change.
Jonathan Carter, director of gynaecological oncology at the Chris O'Brien Lifehouse Cancer Centre in Sydney, spoke with Norman Swan from the ABC's The Health Report to explain the changes to the testing procedure.
"...whilst that (the pap smear) has been a great step forward with a reduction in the incidence of about 50% in patients developing cervical cancers, that incidence has plateaued over recent years," he said.
Now, starting from age 25, a woman will still have a cervical scrape, "but the laboratories will look for the DNA of the HPV virus, which we now know is the causative agent for cervical cancer. So every five years women will be invited to have an HPV test. And if that HPV test is positive, they will have a reflex smear and colposcopy," he explained.
So what about women under the age of 25?
Karen Canfell of the Cancer Council New South Wales explains research indicates that papsmears have resulted in "... this great reduction of 50% or more in women over the age of 25, and in fact that reduction holds over beyond the age of stopping screening. So we found this similar reduction even in women over the age of 70 who aren't targeted by the screening program. So that's fantastic. It shows that there is long-term hold-over benefits from regular screening. We found that there were no changes in rates in younger women under the age of 25," she explains.
Cervical cancer is very rare in women under the age of 25 and screening has had no impact on the detection of early stage cervical cancer in women in this age group. The impact of the HPV vaccine has been huge with the collapse of HPV infections in younger women. Greater than 99% of all cervical cancers contain HPV virus. So if a woman is HPV negative, the risk for having precancer is extraordinarily low.
Is HPV testing going to affect adenocarcinoma?
Johnathon Carter said, "because 80% or more, in fact even more than squamous cells cancers are caused by the HPV virus. So HPV testing and HPV vaccination is predicted to impact these in a much more cognisant way than the Pap smear screening program has been able to."
"...there are lesions within the cervix that may not be reached by a standard Pap smear. And the Pap smear itself, its accuracy is…in the order of 60% to 70%," he said.
Karen Canfell summarises, "the biggest change at the moment is that (starting in 2017) we will send a proactive invitation to the woman to screen on her 25th birthday, and then proactive invitations every five years thereafter. So certainly that doesn't take away from the GPs management, but it really means that we will have a good central system in place for reminding women."
"So the beauty of the move to HPV screening is that in fact it doesn't matter what a woman's past vaccination status is, we will be able to basically assess her risk based on the HPV result that we find," she said.
Dr Norman Swan. Changes to Cervical Cancer Screening. The Health Report. ABC Radio National. 17 Oct 2016.
Smith M, Canfell K. Impact of the Australian National Cervical Screening Program in women of different ages. Med J Aust 2016; 205 (8): 359-364
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