INTRAEPITHELIAL AND INVASIVE SQUAMOUS-CELL NEOPLASIA OF THE VULVA - TRENDS IN INCIDENCE, RECURRENCE, AND SURVIVAL RATE IN NORWAY

Objective: To characterize time trends in incidence of intraepithelial and invasive vulvar neoplasia, transition of intraepithelial vulvar n eoplasia to invasive cancer, and survival rate based on a total popula tion. Methods: The Cancer Registry of Norway was used to identify all Norwegian inhabitants diagnosed during 1956-1990 with squamous cell ca rcinoma of the vulva, and all those with intraepithelial vulvar neopla sia diagnosed during 1973-92. Results: The incidence rate of intraepit helial 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 squamou s 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 ex cess death rate by increasing age. Conclusion: The incidence of vulvar intraepithelial neoplasia has increased substantially over the last 4 0 years, but that of invasive vulvar cancer has not changed appreciabl y. (C) 1998 by The American College of Obstetricians and Gynecologists .