RESUMEN
BACKGROUND: To assess the amount of breast cancer overdiagnosis associated with the National Health Service Breast Screening Programme (NHSBSP) that started in 1988 in England. METHODS: First, numbers of breast cancers in women eligible for breast screening not attending screening were estimated for the period 1995-2019, which were extrapolated to all women. A second method was based on ratios of incidence rates of breast cancers in women aged 50-69 to women aged 70 years or more in 1971-1985. The ratio was used for estimating expected numbers of cancers in 1988-2019, and 1995-2019. RESULTS: From 1995 to 2019, 506,607 non-invasive and invasive breast cancers were diagnosed among women aged 50-64 years (1995-2001) and 50-70 years (2002-2019). A first method estimated that 95,297 cancers were in excess to the number of cancers that would be expected had the NHSBSP not existed. 42,567 screen-detected non-invasive and micro-invasive cancers represented 45.8% of the total excess cancer. 18.8% of all cancers diagnosed among women invited to screening, 25.1% of cancers found in women attending screening, and 35.1% of cancers detected by screening would represent overdiagnosis. A second method estimated that, 18.0% of all cancers diagnosed in 1988-2019, and 18.2% of all cancers diagnosed in 1995-2019 among women invited to screening would represent overdiagnosis. CONCLUSION: The two independent methods obtained similar estimates of overdiagnosis. The NHS Breast Screening Programme in England is associated with substantial amount of overdiagnosis.
RESUMEN
BACKGROUND: Obesity is a risk factor for endometrial cancer but whether metabolic dysfunction is associated with endometrial cancer independent of body size is not known. METHODS: The association of metabolically defined body size phenotypes with endometrial cancer risk was investigated in a nested case-control study (817 cases/ 817 controls) within the European Prospective Investigation into Cancer and Nutrition (EPIC). Concentrations of C-peptide were used to define metabolically healthy (MH; <1st tertile) and metabolically unhealthy (MU; ≥1st tertile) status among the control participants. These metabolic health definitions were combined with normal weight (NW); body mass index (BMI)<25 kg/m2 or waist circumference (WC)<80 cm or waist-to-hip ratio (WHR)<0.8) and overweight (OW; BMI≥25 kg/m2 or WC≥80 cm or WHR≥0.8) status, generating four phenotype groups for each anthropometric measure: (i) MH/NW, (ii) MH/OW, (iii) MU/NW, and (iv) MU/OW. RESULTS: In a multivariable-adjusted conditional logistic regression model, compared with MH/NW individuals, endometrial cancer risk was higher among those classified as MU/NW [ORWC, 1.48; 95% confidence interval (CI), 1.05-2.10 and ORWHR, 1.68; 95% CI, 1.21-2.35] and MU/OW (ORBMI, 2.38; 95% CI, 1.73-3.27; ORWC, 2.69; 95% CI, 1.92-3.77 and ORWHR, 1.83; 95% CI, 1.32-2.54). MH/OW individuals were also at increased endometrial cancer risk compared with MH/NW individuals (ORWC, 1.94; 95% CI, 1.24-3.04). CONCLUSIONS: Women with metabolic dysfunction appear to have higher risk of endometrial cancer regardless of their body size. However, OW status raises endometrial cancer risk even among women with lower insulin levels, suggesting that obesity-related pathways are relevant for the development of this cancer beyond insulin. IMPACT: Classifying women by metabolic health may be of greater utility in identifying those at higher risk for endometrial cancer than anthropometry per se.
