Objectives: To determine patient and disease characteristics, treatment patterns and long-term outcomes, in order to help direct management of patients with VIN 3, to examine the risk of development of cancer following a diagnosis of VIN 3 and the risk of recurrent disease requiring multiple treatment episodes, and to review patients with vulval cancer, in order to establish the relative prevalence of VIN 3 related vulval cancers.
Design: Retrospective chart review of 65 consecutive patients diagnosed with VIN 3 between 1989 and 1999.
Population or sample: All patients diagnosed with VIN 3 at Christchurch Womens' Hospital (1 January 1989 to 31 December 1999) and Dunedin Public Hospital (1 January 1990 to 31 December 1999).
Main outcome measures: Age at diagnosis, symptoms, medical history disease characteristics, treatment, outcome and follow-up.
Results: The median age at diagnosis was 38 years. Smokers were younger than non-smokers. Two-thirds had associated dysplasia of the lower genital tract, 43% had high-grade lesions. Seventy-nine per cent were symptomatic for a median of 9.5 months. All had macroscopically visible disease. Colposcopy and histology diagnoses correlated in 72% of cases. Treatment by local excision was undertaken in 84% of cases of which 65% had involved margins. Fifty-one per cent required further treatment, risk factors were positive margins and multifocal disease. Three developed micro-invasive cancer.
Conclusions: Treatment by local excision is both diagnostic and therapeutic. Excision may reveal micro-invasive cancer, patients are usually symptomatic and VIN 3 has some potential to become invasive. Treated patients may develop microinvasive disease but frank invasion was not seen. The true rate of malignant progression in untreated patients remains unclear and radical surgery is rarely indicated. All patients require long-term follow up.