Giudici F, De Vidi S, Guzzinati S, Toffolutti F, Dal Maso L, AIRTUM WG.
49th Annual Meeting of the Group for Cancer Epidemiology and Registration in Latin Language Countries (GRELL)
Porto, 27-30 maggio 2025
Abstract
Objectives: Information on cancer progression and recurrence is not routinely collected by cancer registries. This study aims to estimate the risk of metastatic recurrence (MR) for Italian women with early-stage breast cancer (BC).
Methods: Women diagnosed with stage I-III BC in 1997–2017 were selected from 7 population-based Italian cancer registries. We used a novel modelling method recently developed for SEER registries, based on an illness–death process coupled with a mixture cure model for relative survival after cancer. MR risk was estimated by combining registry survival data from women with de novo metastatic BC with data from studies reporting survival from recurrent disease. MR risks were calculated according to age and stage of disease, in terms of cumulative risk up to 15 years and conditional on being alive and MR-free after 5 and 10 years.
Results: The analysis included 59,968 women aged 15-74 years, half of them with a Stage I disease. The risk of MR at 15 years
decreased from 20.3% in 1997-2006 to 12.3% in 2007-2017. Focusing on the recent period, 2007-2017, MR risk within 15 years was 3.0% for stage I, 16.0% for stage II, and 42.7% for stage III BC. The conditional probabilities of MR decreased with time, in particular women with stage III BC had a MR risk of 31.0% in the first 5 years which became 4.2% between 10 and 15 years since diagnosis. The conditional MR risks for women of all ages with Stage I became less than 2% between year 10 and 15 after diagnosis.
Conclusions. This study provides the first population-based estimate of long-term metastatic recurrence risk for Italian women with BC. Moreover, information on the conditional risks of MR may help personalise follow-up through an informative risk stratification.