Survival After Palliative Radiotherapy in Patients with Breast Cancer and Bone-only Metastases

Patients with bone-only metastases survive longer than patients with widespread visceral disease. We analyzed the prognostic impact of different baseline parameters, such as abnormal blood tests and receptor status in patients who received local radiotherapy, in addition to contemporary systemic treatment, according to national guidelines.

Retrospective uni- and multivariate analyses of 57 consecutive female patients treated in the time period 2007-2014 (median follow-up=29 months).

The median age was 59 years and the median time interval from the initial diagnosis of breast cancer was 57 months. The median survival was 23 months from radiotherapy and 32 months from initial diagnosis of metastatic disease. Five-year survival rates were 13 and 21%, respectively. Survival after radiotherapy was significantly longer in patients who were prescribed higher radiation doses; 29 months after ≥30 Gy and 10 months after <30 Gy, p=0.02. Multivariate analysis confirmed 4 independent prognostic factors for shorter survival: triple-negative histology (p=0.0001), high serum lactate dehydrogenase (LDH) (p=0.001), high serum alkaline phosphatase (ALP) (p=0.015) and intended radiation dose <30 Gy (p=0.028). A 3-tiered prognostic score with median survival of 48, 21 and 12 months was developed.

Prognosis varied widely with many patients surviving for several years. The results of simple blood tests provided important prognostic information. Prospective studies are necessary to confirm that more aggressive radiotherapy improves survival in patients with bone-only disease suitable for local therapy.