Scientists say that stopping smoking may boost the woman's immune system and enable it to deal with abnormal cells, preventing any further adverse changes. Smoking is thought to weaken the immune response in the cervix.
Dr Anne Szarewski, of the Imperial Cancer Research Fund which carried out the study, said: "The results suggest that it is well worth women trying to stop smoking if their smear test shows mild abnormality. They might even be able to avoid having treatment at a later date."
A group of 82 women smokers with abnormal-looking areas on the cervix agreed to try to give up smoking for six months. Seventeen stopped completely and eleven cut down by more than three-quarters. The quitters and the non-quitters were similar in age, contraceptive use, menstrual cycles and sexual habits.
After six months, more than 80 per cent of those who had quit or reduced their smoking by at least 75 per cent showed a reduction in the size of the abnormal-looking area, compared with less than 20 per cent of those who continued to smoke. "The more the women reduced their smoking the greater was the reduction in the size of the lesion on the cervix," the ICRF says.
Previous studies have suggested a strong link between smoking and cervical cancer, Dr Szarewski said. "However, it has not been altogether clear whether this is due to smoking per se or something else to do with lifestyle. This study is unique in trying to find out whether stopping smoking causes abnormal-looking areas on the cervix to get smaller."
There is also evidence that smoking can weaken the cervix's immune response against viruses - a virus is implicated in cervical cancer - bacteria and other toxins.
"Smoking cessation may be allowing the immune system to recover, leading to a reduction in size of mild cervical lesions," Dr Szarewski added. "Our study adds to the evidence supporting a direct link between smoking and cervical disease."
In their report, published in tomorrow's issue of the Lancet, the ICRF scientists point out that quitting or cutting down on smoking could affect only those lesions that are unlikely to become cancerous. However, they conclude that "women with early cervical abnormalities may benefit from smoking cessation".Reuse content