A Herbert1, M Gregory, S S Gupta, N Singh. 1. Histopatholoy Department, Southampton University Hospitals Trust, Southampton, UK. amanda.herbert@kcl.ac.uk
Abstract
OBJECTIVE: To examine screening histories of women with invasive cervical cancer in a 12-year period during the introduction of organised screening to assess its effectiveness. STUDY DESIGN: Screening histories were classified into six categories: no cytology record (1), previous cytology more than 5 years before diagnosis (2) and previous cytology within 5 years of diagnosis (3-6). Categories 3-6 were described as interval cancers and comprised previous negative cytology (3), previous repeats for low-grade cytology (4), previous recommendations for investigation (5) and previous treatment (6). SETTING: Southampton and South West Hampshire (SSWH). POPULATION: Women resident in SSWH registered with invasive cervical carcinoma between 1985 and 1996. METHODS: Data were held for analysis on an anonymous spreadsheet. MAIN OUTCOME MEASURES: Association of screening history categories with 3-year time period, age group, type and stage of cancer and route to diagnosis; incidence per 100,000 women aged 25-64 years screened and not screened within 5 years in 1991-93 and 1994-96. RESULTS: Interval cancers increased as a proportion of all cancers from 31.5% in 1985-87 to 48.6% in 1994-96 (P= 0.002) and showed a peak in 1991-93. Their incidence decreased from 20.1 to 10.9 per 100 000 eligible women aged 25-64 years screened within 5 years (P= 0.008) between 1991-93 and 1994-96, while incidence in women not screened within 5 years was unchanged (44.2 and 40.4). Factors other than previous negative smears were recorded in 50.9% of interval cancers. Interval cancers were more likely to be low stage, screen detected and were diagnosed in younger women (P < 0.00001). CONCLUSIONS: Interval cancers should be assessed as a proportion of eligible women screened within the same period of time and not as a proportion of all cancers. This audit demonstrates the importance of accurate cytology, appropriate follow up, prompt investigation and effective treatment of high-grade precancerous lesions.
OBJECTIVE: To examine screening histories of women with invasive cervical cancer in a 12-year period during the introduction of organised screening to assess its effectiveness. STUDY DESIGN: Screening histories were classified into six categories: no cytology record (1), previous cytology more than 5 years before diagnosis (2) and previous cytology within 5 years of diagnosis (3-6). Categories 3-6 were described as interval cancers and comprised previous negative cytology (3), previous repeats for low-grade cytology (4), previous recommendations for investigation (5) and previous treatment (6). SETTING: Southampton and South West Hampshire (SSWH). POPULATION: Women resident in SSWH registered with invasive cervical carcinoma between 1985 and 1996. METHODS: Data were held for analysis on an anonymous spreadsheet. MAIN OUTCOME MEASURES: Association of screening history categories with 3-year time period, age group, type and stage of cancer and route to diagnosis; incidence per 100,000 women aged 25-64 years screened and not screened within 5 years in 1991-93 and 1994-96. RESULTS:Interval cancers increased as a proportion of all cancers from 31.5% in 1985-87 to 48.6% in 1994-96 (P= 0.002) and showed a peak in 1991-93. Their incidence decreased from 20.1 to 10.9 per 100 000 eligible women aged 25-64 years screened within 5 years (P= 0.008) between 1991-93 and 1994-96, while incidence in women not screened within 5 years was unchanged (44.2 and 40.4). Factors other than previous negative smears were recorded in 50.9% of interval cancers. Interval cancers were more likely to be low stage, screen detected and were diagnosed in younger women (P < 0.00001). CONCLUSIONS:Interval cancers should be assessed as a proportion of eligible women screened within the same period of time and not as a proportion of all cancers. This audit demonstrates the importance of accurate cytology, appropriate follow up, prompt investigation and effective treatment of high-grade precancerous lesions.