Background: One of the most consistent models for estimating personalized breast cancer (BC) risk is the Tyrer-Cuzick algorithm that is incorporated into the International Breast Cancer Intervention Study (IBIS) software. Our main objective was to provide criteria for the classification of the Slovenian population, which has BC incidence below the European average, into risk groups, and to evaluate the integration of the criteria in Slovenian guidelines. Our main focus was on women age <50 with higher BC risk, since no organized BC screening is available for these women.
Methods: Slovenian age-specific BC risks were incorporated into IBIS software and threshold values of risk categories were determined. Risk categories were assigned according to the individual's ten-year risk for women aged 40 and older, and lifetime risk for women between 20 and 39. To test the software, we compared screening strategies with the use vs. no use of IBIS.
Results: Of the 197 women included in the study IBIS assigned 75.1% to the BC risk group, and the rest to the moderately increased risk. Without IBIS 80 women were offered mammographic and 33 ultrasound screening. In contrast, 28 instead of 80 would have been offered mammographic screening and there would have been no referrals for ultrasound if IBIS had been used.
Conclusions: The Slovenian IBIS has been developed, tested and suggested for personalized breast cancer risk assessment. The implementation of the software with the consideration of Slovenian risk thresholds enables a more accurate and nationally unified assessment.
Uvod: Trenutno je kot najdoslednejši model za oceno individualizirane ogroženosti za raka dojk razpoznan Tyrer-Cuzickov algoritem, vključen v program IBIS (International Breast Cancer Intervention Study), ki temelji na angleških podatkih o incidenci raka dojk. Glavni cilj naše raziskave je bil postaviti merila za razvrščanje slovenskih žensk, ki imajo ogroženost za raka dojk pod evropskim povprečjem, v skupine ogroženosti glede na izračun ogroženosti z uporabo programa IBIS. Prav tako smo želeli oceniti morebitno vpeljavo teh meril v slovenske smernice. Poseben poudarek je namenjen bolj ogroženim pod petdesetim letom starosti, saj za ženske v teh starostnih skupinah nimamo organiziranega presejanja.
Metode: V program IBIS smo umestili slovensko generacijsko specifično incidenco raka dojk in določili mejne vrednosti skupin ogroženosti (populacijska, zmerno povečana in visoka). Skupine ogroženosti so bile določene na podlagi 10-letne ogroženosti za ženske, ki so stare 40 let ali več, in doživljenjske ogroženosti za ženske, stare med 20 in 39 let. S programom IBIS smo izračunali ogroženost za raka dojk za ženske, ki so prišle na preventivni pregled v okviru primarnega in sekundarnega zdravstvenega varstva, in primerjali priporočila, ki so bila svetovana po pregledu, s priporočili, ki bi veljala, če bi uporabili program IBIS.
Rezultati: V raziskavo smo vključili 197 žensk in za vsako posameznico izračunali ogroženost za raka dojk s pomočjo programa IBIS. Program je 75,1 % žensk umestil v skupino populacijsko ogroženih, ostale pa v skupino zmerno povečane ogroženosti. Brez uporabe IBIS-a je bilo 80 žensk umeščeno v bolj ogroženo skupino, opravile so presejalno mamografijo, 33 ženskam pa so opravili ultrazvočno preiskavo dojk. Če bi uporabili nova merila razvrščanja v skupine ogroženosti s pomočjo izračuna programa IBIS, bi jih 28 namesto 80 opravilo presejalno mamografijo. Prav tako ne bi nobene ženske po novih merilih poslali na ultrazvočno preiskavo dojk.
Zaključki: Razvili smo program IBIS, ki vsebuje slovensko populacijsko incidenco raka dojk. Program smo testirali in predlagali za orodje izračunavanja individualizirane ogroženosti za raka dojk. Uvedba programa bi, ob upoštevanju enotnih mejnih vrednosti kategorij ogroženosti, omogočala natančnejšo in bolj poenoteno obravnavo žensk na državni ravni.
Keywords: Tyrer-Cuzick model; breast cancer; breast cancer risk assessment; personalized breast cancer screening.
© 2020 Mateja Krajc, D Gareth Evans, Ana Blatnik, Katarina Lokar, Tina Žagar, Sonja Tomšič, Janez Žgajnar, Vesna Zadnik, published by Sciendo.