Lauro Bucchi1, Alessandra Ravaioli2, Flavia Baldacchini1, Orietta Giuliani1, Silvia Mancini1, Rosa Vattiato1, Paolo Giorgi Rossi3, Cinzia Campari4, Debora Canuti5, Enza Di Felice5, Priscilla Sassoli de Bianchi5, Stefano Ferretti6, Nicoletta Bertozzi5, Fabio Falcini1,7. 1. Romagna Cancer Registry, Romagna Cancer Institute (IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) "Dino Amadori"), Meldola, Forlì, Italy. 2. Romagna Cancer Registry, Romagna Cancer Institute (IRCCS Istituto Romagnolo per lo Studio dei Tumori (IRST) "Dino Amadori"), Meldola, Forlì, Italy. alessandra.ravaioli@irst.emr.it. 3. Epidemiology Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy. 4. Cancer Screening Unit, Azienda Unità Sanitaria Locale - IRCCS di Reggio Emilia, Reggio Emilia, Italy. 5. Department of Health, Regional Administration, Emilia-Romagna Region, Bologna, Italy. 6. University of Ferrara and Local Health Authority, Ferrara, Italy. 7. Local Health Authority, Forlì, Italy.
Abstract
OBJECTIVE: The European Commission Initiative on Breast Cancer recommendation for triennial screening of women aged 70-74 is based on very weak evidence. A cohort of Italian women who had their last biennial screening mammography at age 68-69 was followed up for 5 years, assumed to represent the interval to another hypothetical screening mammography, in order to determine the annual proportional incidence of interval breast cancer. METHODS: The cohort included 118,370 women. They had their last mammography between 1997 and 2008. Incident breast cancers were identified by record-linking the cohort with the regional breast cancer registry. The expected incidence in the age range 65-74 was estimated with an age-period-cohort model. The number of interval cancers was divided by the expected number to obtain their proportional incidence. RESULTS: Overall, there were 298,658 woman-years at risk with 371 interval cancers versus 988.8 expected. In the first, second, third, fourth, and fifth interval year, the proportional incidence was 0.09 (95% confidence interval, 0.06-0.13), 0.32 (0.25-0.39), 0.60 (0.49-0.73), 0.75 (0.60-0.92), and 0.81 (0.60-1.07), respectively. Between the second and the fifth year, tumour stage and molecular subtype did not change significantly. CONCLUSION: Though not supported by these findings, the proposal of triennial screening for women aged 70-74 merits further research, because the 95% confidence interval of the third-year proportional incidence of interval cancer included 0.50-the maximum limit considered acceptable for women aged 50-69. KEY POINTS: • The third-year incidence of breast cancer relative to the expected one was 0.60 (95% confidence interval, 0.49-0.73). • Between the second and the fifth year, tumour stage and molecular subtype did not change significantly (p >0.10). • The proposal of a 3-year screening interval at age 70-74 merits further evaluation.
OBJECTIVE: The European Commission Initiative on Breast Cancer recommendation for triennial screening of women aged 70-74 is based on very weak evidence. A cohort of Italian women who had their last biennial screening mammography at age 68-69 was followed up for 5 years, assumed to represent the interval to another hypothetical screening mammography, in order to determine the annual proportional incidence of interval breast cancer. METHODS: The cohort included 118,370 women. They had their last mammography between 1997 and 2008. Incident breast cancers were identified by record-linking the cohort with the regional breast cancer registry. The expected incidence in the age range 65-74 was estimated with an age-period-cohort model. The number of interval cancers was divided by the expected number to obtain their proportional incidence. RESULTS: Overall, there were 298,658 woman-years at risk with 371 interval cancers versus 988.8 expected. In the first, second, third, fourth, and fifth interval year, the proportional incidence was 0.09 (95% confidence interval, 0.06-0.13), 0.32 (0.25-0.39), 0.60 (0.49-0.73), 0.75 (0.60-0.92), and 0.81 (0.60-1.07), respectively. Between the second and the fifth year, tumour stage and molecular subtype did not change significantly. CONCLUSION: Though not supported by these findings, the proposal of triennial screening for women aged 70-74 merits further research, because the 95% confidence interval of the third-year proportional incidence of interval cancer included 0.50-the maximum limit considered acceptable for women aged 50-69. KEY POINTS: • The third-year incidence of breast cancer relative to the expected one was 0.60 (95% confidence interval, 0.49-0.73). • Between the second and the fifth year, tumour stage and molecular subtype did not change significantly (p >0.10). • The proposal of a 3-year screening interval at age 70-74 merits further evaluation.