Messaggi chiave
- Alcune evidenze di letteratura suggeriscono che il rischio di sviluppare un secondo carcinoma mammario primario (SPBC) sia maggiore nelle donne di età ≤40 anni alla diagnosi del primo tumore. È stato pertanto condotto uno studio volto a stimare l’incidenza cumulativa a 5 e 10 anni di SPBC in una coorte di pazienti BC in giovane età.
- L’analisi ha incluso 658 donne con anamnesi di mastectomia unilaterale o lumpectomia provenienti dalla popolazione di Young Women’s Breast Cancer Study, uno studio prospettico condotto in 1297 pazienti di età ≤40 anni con diagnosi di BC in stadio 0-III ricevuta nel periodo 2006-2015.
- Nell’arco di un follow-up mediano di 10 anni, il 2,5% delle pazienti ha sviluppato un SPBC. L’incidenza cumulativa a 10 anni è risultata pari al 2,2% nelle donne non portatrici di una variante patogenetica germinale rispetto all’8,9% nelle portatrici. Questi risultati evidenziano l’importanza del test genetico nelle pazienti giovani per stimare il rischio di secondo tumore primario e modulare di conseguenza le decisioni terapeutiche e l’intensità del follow-up.
Abstract
Importance
- Among women diagnosed with primary breast cancer (BC) at or younger than age 40 years, prior data suggest that their risk of a second primary BC (SPBC) is higher than that of women who are older when they develop a first primary BC.
Objective
- To estimate cumulative incidence and characterize risk factors of SPBC among young patients with BC.
Design, Setting, and Participants
- Participants were enrolled in the Young Women’s Breast Cancer Study, a prospective study of 1297 women aged 40 years or younger who were diagnosed with stage 0 to III BC from August 2006 to June 2015. Demographic, genetic testing, treatment, and outcome data were collected by patient surveys and medical record review.
- A time-to-event analysis was used to account for competing risks when determining cumulative incidence of SPBC, and Fine-Gray subdistribution hazard models were used to evaluate associations between clinical factors and SPBC risk. Data were analyzed from January to May 2023.
Main Outcomes and Measures
- The 5- and 10- year cumulative incidence of SPBC.
Results
- In all, 685 women with stage 0 to III BC (mean [SD] age at primary BC diagnosis, 36 [4] years) who underwent unilateral mastectomy or lumpectomy as the primary surgery for BC were included in the analysis.
- Over a median (IQR) follow-up of 10.0 (7.4-12.1) years, 17 patients (2.5%) developed an SPBC; 2 of these patients had cancer in the ipsilateral breast after lumpectomy. The median (IQR) time from primary BC diagnosis to SPBC was 4.2 (3.3-5.6) years. Among 577 women who underwent genetic testing, the 10-year risk of SPBC was 2.2% for women who did not carry a pathogenic variant (12 of 544) and 8.9% for carriers of a pathogenic variant (3 of 33).
- In multivariate analyses, the risk of SPBC was higher among PV carriers vs noncarriers (subdistribution hazard ratio [sHR], 5.27; 95% CI, 1.43-19.43) and women with primary in situ BC vs invasive BC (sHR, 5.61; 95% CI, 1.52-20.70).
Conclusions
- Findings of this cohort study suggest that young BC survivors without a germline pathogenic variant have a low risk of developing a SPBC in the first 10 years after diagnosis.
- Findings from germline genetic testing may inform treatment decision-making and follow-up care considerations in this population.