A woman who has been treated for pre-cancerous lesions of the cervix or vagina is still at raised risk of developing invasive cancer of the cervix or vagina twenty-five years later. Experts say cytological smears should be done regularly for at least 25 years after a patient has had severe carcinoma in situ (dysplasia/CIS).
You can read about this in the British Medical Journal.
Even though CIS is not cancer, it is fairly close to it. The cells look like cancer, however, they are not located in any tissue – they are superficially in the soft skin-like layer that lines many body cavities, such as the genital and nasal passages (mucosa).
Scientists looked at information from the National Swedish Cancer Register. The information, involving 132,493 women, spanned from 1958 to 2002 – all the women had had a diagnosis of severe dysplasia/CIS.
The researchers explain that 881 of the women had developed cervical cancer and 111 had vaginal cancer twelve months or later after CIS diagnosis. A woman with that diagnosis runs double the risk of developing cancer, compared to the general female population. The risk of cervical cancer was raised further if the diagnosed woman was older, especially over 50.
The risk also increased as the decades passed as the scientists found that patients were twice as likely to develop invasive cervical cancer after diagnosis of CIS if that diagnosis was made in the period 1991-2000 as in the period 1958-1970. This could be as a result of changes in the forms of treatment in different decades.
The number of observed cases of women developing vaginal cancer was nearly seven times higher than expected, the scientists report.
“Although most women with high-grade dysplasia have been protected from invasive cancer it must be considered a failure of the medical service when women participate in screening, their pre-cancerous lesions are found and they subject themselves to treatment of those lesions, presumably participate in follow-up programmes and still develop invasive cancer,” the writers explain.
Follow up care has been insufficient so far, the authors conclude. Women should be offered cytological smears for at least 25 years post-treatment. Long term follow up must not stop for patients when they are 60 years old if they were older than 35-40 at the time of treatment for CIS.
“Risk of invasive cancer after treatment for cervical intraepithelial neoplasia grade 3: population based cohort study”
Bjorn Strander, Agneta Andersson-Ellstrom, Ian Milsom, Par Sparen
BMJ, doi:10.1136/bmj.39363.471806.BE (published 24 October 2007)
Click here to view Abstract online
Written by: Christian Nordqvist