Vulval intraepithelial neoplasia (VIN) is a skin condition affecting the vulval skin which if left untreated may become cancerous. Distressing symptoms include itching, burning, and soreness of the vulva or painful intercourse. There may be discolouration and various other visible changes to the vulval skin. There are two types of VIN: the most common type is associated with infection of the cells of the vulva with a virus called human papilloma virus (now known as usual type VIN), whereas the other type is not associated with this viral infection (now known as differentiated VIN). VIN is becoming more common in younger women. At the moment treatments are aimed at relieving distressing symptoms and ensuring that the condition does not become cancerous. At present the most common treatment option for women with this condition is surgery to remove the affected skin areas. Surgery however does not guarantee a cure and can be disfiguring, and may result in physical and psychological problems in younger women who are sexually active. The purpose of this review was to identify any alternative therapies that can be used to treat this condition safely.
The medical treatments identified included topical treatments such as imiquimod, cidofovir, alpha-interferon (α-IFN), 5-fluorouracil, bleomycine and trinitrochlorobenzene or oral tablets such as indole-3-carbinol (a food additive). Only trials that examined imiquimod and indole-3-carbinol met the inclusion criteria for the review. There is evidence that VIN persists and may progress to cancer when the body's defence system (immune system) does not clear the affected cells. Most of these treatments (imiquimod, indole-3-carbinol, cidofovir and α-IFN) work by enhancing the body's immune system, but some treatments (5-fluorouracil, bleomycine and trinitrochlorobenzene) work by destroying the affected cells. Treatments such as α-IFN and 5-fluorouracil cause distressing local side effects, including painful ulceration of the vulva without proving to be effective to patients, so they are no longer used.
We found four relevant trials (three trials of imiquimod and one of indole-3-carbinol). Although the trials assessing imiquimod included only 104 patients they showed that imiquimod appeared to be effective and reasonably safe in treating high grade VIN. It can cause side effects such as more soreness and itching of the skin over the vulva, but not enough to stop treatment completely. The trials only followed patients for 20 weeks, six months or 12 months so we cannot comment on the longer term outcomes and whether the disease progressed to cancer after 12 months despite treatment. The trial of indole-3-carbinol compared two different doses of the medication which appeared to be safe but we cannot tell if it is as effective as imiquimod or surgery.
More research is needed with larger numbers of patients in order to find an alternative medical treatment for high grade VIN that is safe. Currently imiquimod appears to be reasonably safe and effective but patients need to be monitored closely long term.