Interval cervical cancer following treatment for cervical intraepithelial neoplasia.

The objective of this study was to determine whether those women who developed cervical cancer following treatment for preinvasive disease had common features in their history which could identify those at increased risk of progression and therefore be used to modify management protocols. A retrospective case note review from clinical and histopathologic records was undertaken at a teaching hospital in Wessex, Southern England. The review included 33 women diagnosed with cervical carcinoma between 1985 and 1996 who had previously undergone treatment for cervical intraepithelial neoplasia (CIN) or cervical glandular intraepithelial neoplasia (CGIN). The diagnosis prior to treatment was CIN 3 in 19 cases, CGIN 3 in 2 cases, CIN 2 in 9 cases (97% high grade CIN/CGIN) and CIN 1 in 1 case. At primary treatment, among those treated by knife cone biopsy or Large Loop Excision of the Transformation Zone (LLETZ), and for whom the margins of the treatment specimen were reported, 14 out of 15 had incomplete margins. Local ablation (in which completeness of excision could not be histologically assessed) was performed in 12 cases. In 58% (19/33) of cases, the patient was 40 years or older at the time of initial treatment. Fifteen women had one or more negative smears after treatment, of which only 6 had transformation zone sampling. The interval between treatment of CIN/CGIN and diagnosis of invasion ranged from 8 to 216 months. (mean 40.4 months), with 67% of cases of invasive cancer occurring within 5 years of treatment for CIN/CGIN and 94% within 10 years. Screen detection was achieved in 91% (30/33) of cases with 53% diagnosed while stage 1A. In conclusion, most treatment screen detection of invasive disease at an early (and often microinvasive) stage was achieved for most patients, although a third of patients were diagnosed more than 5 years after initial treatment. The data suggest the need to follow up longer than 5 years when there are risk factors such as incomplete excision of high grade CIN/CGIN and in women over 40 years of age at the time of initial diagnosis.