Ten years after cryosurgical treatment of cervical intraepithelial neoplasia

Long-term risk of invasive cervical cancer after treatment of squamous cervical intraepithelial neoplasia

Invasive cancer of the cervix after treatment for cervical intraepithelial neoplasia (CIN) is becoming more important, as screening reduces the incidence of invasive disease. The rate of invasive cervical or vaginal cancer following treatment for CIN in UK remains elevated for at least 8 years. The aim of our study was to determine from international data how long this rate remains elevated and whether the rate of invasive disease reflects the rate of posttreatment CIN. The aim was to determine why the rate of invasive disease does not fall. A search of Medline and a secondary search of cited references identified 1,848 articles referring to the success rate of the treatment of CIN. Only 26 cohorts from 25 articles met all the inclusion criteria. The policy in these was to perform at least annual smears. After the first year following treatment for CIN, the rate of invasive disease remained about 56 per 100,000 woman years until at least 20 years after treatment. This rate is approximately 2.8 times greater than expected. In contrast, the risk of posttreatment CIN declined steadily with time to about 190 per 100,000 women in the 10th year. Although the posttreatment rate of CIN falls with time, the rate of invasive disease remains static. It seems likely that this is due to diminishing compliance with follow-up. Women should be encouraged to persevere with annual smears for at least 10 years after their treatment as this may offer them the best chance of detecting recurrence at a treatable stage.

Management of cervical premalignant lesions

Management of cervical preneoplasia starts with an abnormal smear result. The use of the Bethesda system is recommended. The management of patients with low-grade abnormal smear results varies around the world. Patients with atypical squamous cells on cytology are recommended to be subclassified into atypical squamous cells of undetermined significance (ASCUS) and atypical squamous cells where high-grade squamous intra-epithelial lesions (HSIL) cannot be excluded (ASCH) groups. While patients with ASCUS can be followed with cytology or colposcopy, the risk of having cervical intra-epithelial neoplasia (CIN) is higher in patients with ASCH. Such patients, as well as those with low-grade squamous intra-epithelial lesions on cytology, should be referred for colposcopy to ensure that diagnosis and treatment in CIN is detected. Patients with HSIL should be referred promptly for colposcopic assessment. This should, usually at the same clinic visit, be followed by large loop excision of the transformation zone (LLETZ). Although this is effective treatment, around 15% of patients will have persistent/recurrent disease on cytological follow-up. Patients with positive human papillomavirus DNA tests at follow-up seem to have a considerably higher risk of recurrent preneoplasia than those who have negative tests. Patients over 50 years of age have much higher recurrence risks than younger patients. These factors impact on second-line treatment and follow-up schedules. An important benefit of conservative treatment for CIN with LLETZ is retention of fertility. LLETZ is associated with an increased risk of preterm prelabour rupture of membranes and preterm birth, but not with other adverse pregnancy outcome measures. Conservative excisional management of adenocarcinoma in situ by LLETZ or cold knife cone biopsy is not reported to be as effective as that of CIN, with high risk of residual and recurrent disease at follow-up. Conversely, LLETZ may be acceptable treatment for micro-invasive squamous carcinoma if the excision margins are free of disease and there is no evidence of lymphovascular involvement. The ability to detect and treat premalignant lesions on the cervix reversed the natural history of cervical cancer. Methods of conservative treatment that evolved over decades have been proven safe and effective, allowing retention of fertility. Good clinical guidelines have been developed for most clinical scenarios while some uncertainties persist for other scenarios.

Outcome of cryosurgery for cervical intraepithelial neoplasia in a developing country

Over a 2-year period cryosurgery was used to treat 73 women who were diagnosed by colposcopy and histologic studies to have cervical intraepithelial neoplasia (CIN). Follow-up was achieved for 70% at 5 years, a significant attendance rate in a developing country. The primary cure rate was 88.5% at 1 year and 90% at 5 years (excluding those lost to follow-up) in all patients with different grades of CIN. The therapy was free of major complications and we found no adverse effect of cryosurgery on subsequent reproductive function in those desiring pregnancy. We conclude that cryosurgery has gained wide acceptance in our geographic area particularly because of its low cost, efficacy and preservation of fertility. For these reasons we would strongly recommend its use provided adequate attention is paid to meticulous pretreatment evaluation and long-term follow-up after therapy.

Invasive cervical cancer after conservative therapy for cervical intraepithelial neoplasia

BACKGROUND

Conservative outpatient therapy for cervical intraepithelial neoplasia (CIN) by ablative or excisional techniques is widely used. The main objective of this treatment is the prevention of invasive cervical cancer. We assessed the rate of invasive disease and the duration of the risk of developing invasive cervical cancer after such treatment.

METHODS

Four UK centres have used life-table methods to analyse the long-term results of conservative treatment of CIN. We combined and updated data from these studies to investigate the rate of invasive disease after treatment and the duration of that risk.

FINDINGS

The data comprised 44 699 woman-years of follow-up, with 2116 women under observation 8 years after treatment. 33 women developed invasive cancer, 14 of whom had microinvasion. The cumulative rate of invasion 8 years after treatment was 5.8 per 1000 women and the rate of invasive cancer during this period was 85 (95% CI 60-119) per 100,000 woman-years. The risk of developing cancer did not change throughout the 8 years of follow-up.

INTERPRETATION

These data show that conservative outpatient therapy in women with CIN reduces the risk of invasive cancer of the cervix by 95% during the first 8 years after treatment. However, even with careful, long-term follow-up, the risk of invasive cervical cancer among these women is about five times greater than that among the general population of women throughout that period. Careful follow-up is essential for at least 10 years after conservative treatment of CIN.

Cervical Cancer: Screening and Prevention of Invasive Disease

Cancer of the cervix is one of the leading causes of cancer-related deaths in women in the United States and accounts for more cancer deaths than any other cancer in third-world countries. Various screening procedures have been developed, but many issues need to be resolved for cervical cancer screening to be effective. Large segments of the population who do not undergo regular screening account for most of the patients with invasive cancers in the United States and worldwide. Allocation of resources and widespread educational programs for these target populations are needed to promote adequate cytologic screening programs and to reduce the death rate from squamous carcinoma of the cervix.