In 429 women with the diagnosis of cancer in situ (CIS), we found, during a follow-up time of 10 years, a relapse frequency of 5.3%; conization was the primary treatment in 414 cases, in 13 cases hysterectomy and radiotherapy in 2 cases. We found that the mean age was significantly higher (p less than 0.01) when the primary CIS lesion was localized in the cervix (36.8 +/- 10.5) compared to localization only on the portio (31.3 +/- 8.7). The risk of relapse was significantly higher (p less than 0.05) in patients where the primary cone had the lesion localized in the cervix compared to the patients where the primary cone had the lesion localized only to the portio. We found that the localization of PAD relapses appearing later compared to a high degree (about 65%) with the localization of the primary CIS lesion. Vaginal relapse was, generally speaking, twice as common when the primary CIS lesion was localized in the cervix compared to when it was localized on the portio alone. Alternative treatment methods to the conization operation are discussed and an increased individualization of CIS treatment is emphasized particularly with consideration to age and the localization of the CIS lesion.