Last updated March 8, 2018 at 10:12 am
Younger women may be better off having regular monitoring rather than immediate treatment according to a new study.
Traditional pap smear tests look for abnormal cellular growth on the cervix. These lesions are not cancer yet, and are called cervical intra-epithelial neoplasia (CIN) and are graded 1, 2 or 3 according to the severity of change. CIN cells can progress towards cancer, but can also return to normal (regress), or remain the same.
Currently, detection of CIN2 lesions are the cut-off point for women receiving treatment, which can include removal of the abnormal tissue or treatment with laser therapy. These treatments are not without side effects though, especially for younger women as treatment can cause problems for future pregnancies.
How often do pre-cancerous cells go back to normal?
Maria Kyrgiou from Imperial College London led a large international team of researchers to try and find out how often CIN2 cells return back to normal cells.
They analysed 36 studies involving 3,160 women diagnosed with CIN2 lesions, and measured how they progressed over a five-year period.
After two years, half of the CIN2 lesions are regressed back to normal cells, one third stayed at the same CIN2 level, and just under one in 5 (18%) progressed to CIN3 or worse.
For young women the regression rate was even higher, with 60% of CIN2 lesions regressing over two years.
“Most CIN2 lesions, particularly in women aged less than 30, regress spontaneously. Active surveillance, rather than immediate intervention, is therefore justified, especially among young women who are likely to adhere to monitoring.” Conclude the study authors, although they add that their findings “should be interpreted with caution”.
So what does this mean for current treatment options?
While this study provides more information to women making a choice about managing a diagnosis of CIN2, it “still means taking a gamble that surveillance is simply delaying treatment and even a small risk of cancer (0.5% in this study) may still be unacceptable to some,” writes Prof Maggie Cruickshank, a cervical cancer specialist at the Aberdeen Maternity Hospital.
While it might be reassuring to know the regression rates, “they must be presented in a meaningful way alongside clear information about the effects of both surveillance and treatment, so women can make fully informed choices.”
Prof Ron Jones, who wrote a book about the disturbing violations of medical ethics around cervical cancer screening in New Zealand in the 1960s and 70s, agrees.
“It’s an excellent review and meta-analysis, but I think it’s important to say that it has a number of limitations, the first is that it is short-term. It is only two years and the natural history of these lesions is more likely to be in decades rather than years and second, there is considerable heterogeneity between the studies.”
“The fact of the matter is 15 women developed cancer in this study. Ask these women whether they were happy to be included in the studies.They talk about regression being 50 per cent at two years – great, but what about the 32 per cent who persist? In my experience, not every woman will return for follow-up when you ask them to, often for good reason.”
“Many women are not willing to accept the very smallest risk, even a one per cent risk, so I think you’ve always got to look at it from the women’s perspective”
Recent changes in cervical cancer screening – more accurate, less often.
Since the introduction of the HPV vaccine, there have been changes in cervical screening. Rather than a pap smear test, which looks for abnormal cells, the new Cervical Screening Test looks for HPV infection, which can identify women at higher risk sooner than a pap smear could.
Women aged 25 to 74 should now have a cervical screening test two years after their last pap smear, and if results are normal it only needs to be repeated once every five years.
The study was published in the BMJ.