SP3-5 Incidence of breast cancer in northern Tunisia: trend and projection into 2024

Breast cancer is the most frequent cancer localisation in Tunisian women. With ageing of population, combined to a generation effect, it is very likely that we will see in near future an important rise in breast cancer incidence. Also all the Tunisian data have always shown a high rate of young patients (ages below 35 years) around 11%. This study is designed to establish a forecast of the level of the incidence and of a numbers of cases of breast cancer until 2024 in Northern Tunisia. We also try to foresee the evolution of the percentage of young women. Methods Data given by the Cancer Registry of Northern Tunisia (CRNT) from 1994 to 2003 are used as a baseline for further prediction. This cancer register is covering half of the Tunisian population. Data of the incidence have estimated for the periods 2004–2008; 2009–2013; 2014–2018; 2019–2024. Predictions were based on a Bayesian Age-Cohort model. The implementation of this trial has been carried out by sampling after Gibbs method using WinBugs software. Results The number of cases is growing continuously over the four periods. Thus, in 2019–2024, nearly 2000 cases/year are expected in the Northern part of the country. The standardised incidence will grow from 21.6 cases/100 000 women in 1994–1998 to 46.4 cases/100 000 women in 2019–2024, an increase of 80%. Until the age of 59 the specific rates par age rise moderately, beyond we can observe acceleration. Finally the projection allows a follow-up of the percentage of young women Conclusion The evolution of the percentage of young women show that the modification of the ages pyramid of the general population paired to a cohort effect (the future generations will have a higher risk), will lead to a lowering of this percentage over years. Thus it is very likely that we can9t keep the genetic hypothesis (Tunisian women would have a higher risk due to genetic state).