Incidence of bone metastases and survival after a diagnosis of bone metastases in breast cancer patients

Menée au Royaume-Uni auprès de 7 064 patientes atteintes d'un cancer du sein (durée moyenne de suivi : 8,4 ans), cette étude analyse l'incidence de métastases osseuses ainsi que la survie

Résumé en anglais

Background: Bone is the most common metastatic site associated with breast cancer. Using a database of women with breast cancer treated at Guy's Hospital, London 1976–2006 and followed until end 2010, we determined incidence of and survival after bone metastases

Methods: We calculated cumulative incidence of bone metastases considering death without prior bone metastases as a competing risk. Risk of bone metastases was modelled through Cox-regression. Survival after bone metastases diagnosis was calculated using Kaplan–Meier methodology.

Results: Of the 7064 women, 589 (22%) developed bone metastases during 8.4 years (mean). Incidence of bone metastases was significantly higher in younger women, tumour size >5 cm, higher tumour grade, lobular carcinoma and ≥four positive nodes, but was not affected by hormone receptor status. Median survival after bone metastases diagnosis was 2.3 years in women with bone-only metastases compared with <1 year in women with visceral and bone metastases. There was a trend for decreased survival for patients who developed visceral metastases early, and proportionately fewer patients in this group.

Interpretation: Incidence of bone metastases has decreased but bone metastases remain a highly relevant clinical problem due to the large number of patients being diagnosed with breast cancer.