The long-term use of the oral contraceptive pill could increase the risk of cervical cancer for women who test positive for the human papilloma virus (HPV), according to research published yesterday.
Dr Victor Moreno and his colleagues from the International Agency for Research on Cancer (IARC) - a research arm of the World Health Organisation - looked at oral contraceptive use in 1,900 women with either invasive or "in-situ" cancer of the cervix.They found that women with HPV who used the pill for between five and nine years were about three times more likely to have cervical cancer. Those who had used oral contraceptives for fewer than five years did not have an increased risk.
When the women were tested for the presence of HPV - which is sexually transmitted - 94 per cent of those with invasive cervical cancer, and 72 per cent of those with the pre-invasive form of the disease, were positive for the virus.
"Our results lend support to the existence of an association bet- ween oral contraceptives and HPV. They suggest that long-term users of oral contraceptives should be included in cervical screening programmes," the authors said in an article published in this week's Lancet medical journal.
In a commentary accompanying the research, Prof David Skegg, from the University of Otago, New Zealand, said: "From a public health viewpoint, a key question is the extent to which these effects persist after women stop taking oral contraceptives.
"There is now a need to bring together all the relevant data to quantify any effects and to assess how these might shift the balance of benefits and risk of oral contraception."