Vaccination and screening critical to cervical cancer prevention
Cancer Routine vaccination against human papilloma virus (HPV) and screening tests are playing a key role in reducing women’s risk of developing cervical cancer.
Cervical cancer affects the neck of the womb, or cervix, and is caused by infection with HPV, which spreads through genital skin-to-skin contact. It is the second most common cancer in women under 35. According to estimates, the HPV vaccine could save 400 of the over 900 lives that are lost to this cancer every year in the UK.
The idea is that giving the vaccine before the first sexual contact occurs lowers the chances of contracting the infection and, consequently, developing cervical cancer later in life, says Miss Adeola Olaitan, a consultant gynaecological oncologist at University College London Hospital. “Most women are infected with HPV at some point, and the infection is usually harmless. But occasionally the virus causes changes in the cells of the cervix, which can lead to cancer.”
Olaitan says screening for such changes, which are asymptomatic, is also key to prevention. It allows to detect abnormalities early enough to be treated, and protect women “from developing cervical cancer in the future.”
The screening (or smear) test involves collecting cells from the cervix with a small soft brush. It takes only a few minutes and is not painful.
“The important thing to remember is that this is not a diagnostic test,” says Olaitan. Abnormalities are detected in 20 per cent of cases, according to Cancer Research UK. But their presence does not mean there is cancer in the cervix.
The cells collected during screening are sent to a laboratory for analysis. If the results show mild abnormalities the sample is tested for HPV. Women who test positive are offered a colposcopy (a physical examination of the cervix). Those who test negative are invited back for routine screening. If the smear results show more marked changes a colposcopy is offered without prior HPV testing.
Screening still needed after vaccination
Women are invited for a smear test every three years if aged 25 to 49, or every five years if aged 50 to 64. This currently includes vaccinated women, because the vaccine reduces, but does not eliminate, cancer risk.
“Vaccination protects against HPV 16 and 18, which cause 70 per cent of cervical cancers. It does not protect against all cervical cancer-causing viruses,” says Olaitan. “Vaccinated women shouldn’t therefore feel falsely reassured, and should still attend screening.” Yet in June new research has revealed that, among women over 50 for instance, screening uptake is at an 18-year low of 72 per cent.
“It’s crucial that all age groups attend screening, because this offers the best protection,” says Olaitan. Indeed, scientists estimate that screening lowers cervical cancer risk by 60 to 80 per cent, and saves around 4,500 lives every year in the UK. Since screening began, in the 1980s, cervical cancer cases have decreased by nearly 50 per cent.