Intraepithelial and invasive squamous cell neoplasia of the vulva: trends in incidence, recurrence, and survival rate in Norway

Abstract

Objective: To characterize time trends in incidence of intraepithelial and invasive vulvar neoplasia, transition of intraepithelial vulvar neoplasia to invasive cancer, and survival rate based on a total population.

Methods: The Cancer Registry of Norway was used to identify all Norwegian inhabitants diagnosed during 1956-1990 with squamous cell carcinoma of the vulva, and all those with intraepithelial vulvar neoplasia diagnosed during 1973-92.

Results: The incidence rate of intraepithelial neoplasia increased three-fold from 1973-77 to 1988-92, and 3.4% changed into invasive disease. Multivariate analyses identified age as a significant variable. The age-adjusted incidence rate for squamous cell carcinoma was constant for the whole period. The ratio between recurrence and the total number of invasive cancer varied from 21% to 31%. The 5-year survival rates have not changed significantly over the period. Age was revealed as a strong prognostic factor, showing an excess death rate by increasing age.

Conclusion: The incidence of vulvar intraepithelial neoplasia has increased substantially over the last 40 years, but that of invasive vulvar cancer has not changed appreciably.