Outcomes of screening to prevent cancer: analysis of cumulative incidence of cervical abnormality and modelling of cases and deaths prevented

Abstract

Objective To determine the frequency of different outcomes in women participating in cervical screening. Design Analysis of screening records from 348 419 women, and modelling of cases of cervical cancer and deaths with and without screening. Setting Cervical screening programme in Bristol. Results For every 10 000 women screened from 1976 to 1996, 1564 had abnormal cytology, 818 were investigated, and 543 had abnormal histology. One hundred and seventy six had persistent abnormality for two years or more. In the absence of screening 80 women would be expected to develop cancer of the cervix by 2011, of whom 25 would die. With screening 10 of these deaths would be avoided. Comparison of cumulative abnormality rates with numbers expected to develop cancer in the absence of screening suggests that at least 80% of high grade dyskaryosis and of high grade dysplasia would not progress to cancer. The lifetime risk of having abnormal cytology detected could be as high as 40% for women born since 1960. Conclusions Screening is labour and resource intensive. It involves treatment for many women not destined to develop invasive cancer. The increased intervention rate for cervical abnormality in England is due to change in practice, not a cohort effect, and is probably the reason for the marked fall in incidence and mortality during the 1990s. For other cancers there is scope for major iatrogenic harm from screening because of invasive tests and treatments.

The role of human papillomavirus testing in the management of women with low‐grade abnormalities: multicentre randomised controlled trial

“…High NPVs could be used to rule out further testing. Is an NPV of 97.4% for CIN3 in women over 40, in whom most CIN will not progress, 3 high enough? The possible value of a negative HPV test in women aged 40 or more in enabling cytology test intervals to be extended should be investigated.…”

“…There are substantial cost implications for the women concerned, and for the health services. 3 There has been controversy about the most effective and efficient management of the large numbers of women who have minor cytological abnormalities. 4 The main methods proposed are cytological surveillance or referral for colposcopy.…”

Knowledge of Colorectal Cancer Screening among Young Malaysians

“…For instance, in 2008, only 54% of adults aged 50 years or older were screened for colorectal cancer. In contrast, 75% of women were screened that year for breast cancer and 72% were screened for cervical cancer (Oxentenko et al, 2007;Nelson and Thorson, 2009;Smith et al, 2010). Recent decades have witnessed the mortality reduction in breast and cervical cancers, largely attributed to the screening programs (Blanks et al, 2000;Raffle et al, 2003), and screening for colorectal cancer is emerging (Benson et al, 2008).…”

Cost‐effectiveness of primary cytology and HPV DNA cervical screening

“…53 The sojourn time with screen-detectable HPV infection and CIN is on average 15-20 years on average before invasive cancer. 34,54,55 Because histologic diagnosis of CIN2-3 may vary 5,56 and since most CIN 2-3 lesions will never progress to invasive cancer, 8,57 the majority of women diagnosed with CIN2-3 will have unnecessary treatment. The number of diagnostic procedures, over-treatments and follow-up examinations is reduced by extending screening intervals, resulting in cost savings without changes in the clinical outcome, as found both by us and others.…”

“…[3][4][5] Several studies have evaluated the economic impact of cervical screening with and without HPV testing, but have reported variable results. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22] Possible reasons for discrepancies include different modeling methodologies, use of surrogate endpoints and use of input data based on clinical studies that may not have been representative of the population as a whole. However, most modeling studies have consistently found similar reductions of the cumulative lifetime risk of invasive cervical cancer as a result of cytology and HPV DNA screening.…”