Invasive cervical cancer after treatment of CIN

A historical audit of 30 post-treatment cervical cancers (10% of 289 cancers, 1999-2016) compared with a one-year-equivalent control group treated for cervical intraepithelial neoplasia (CIN) grade 3 (n = 164).

We compared history and follow up of cancer patients and controls and reviewed initial excision biopsies preceding cancer and, in 41% of controls, high-grade recurrence (n = 17) or consistently negative follow-up (n = 51).

Either abnormal post-excision cytology without high-risk human papillomavirus (hrHPV) tests or immediate re-excision was recorded in 70% (19 of 27) of patients with squamous cell carcinoma (SCC). Negative investigations including cytology, colposcopy, re-excision, hysteroscopy, hrHPV, and/or treatment default were recorded in 83% (25 of 30) of all cancers. The mean interval between initial excision and cancer diagnosis was 79.8 ± 30.1 months versus 11.2 ± 30.1 months for CIN3 recurrence. Eight, 13, and 9 patients with cancer had initial excision at age 20-34, 35-49, and 50+ years, respectively, compared with 71%, 23%, and 5% of controls. CIN3 more often preceded SCC than CIN2 (22:1); 5 of 30 initial excisions were originally reported as negative after severe dyskaryosis. No SCC or CIN3 recurrence followed complete excision. Depth of CIN3 2+ mm (20 of 82 reviewed) was strongly associated with cancer/high-grade recurrence or early stromal invasion on review (18 of 20; 90%). Discrepancies were found on review in 10% of biopsies and as occasional abnormal cells in 9 of 34 cytology slides.

Residual disease may be inconspicuous or absent on cytology, colposcopy, and/or histology. Management taking account of risk of recurrence (age, CIN3 depth, incomplete initial excision) could avoid some post-treatment cancers.