Blanchette PS, et al. - Researchers investigated the factors that have an impact on survival among patients treated with trastuzumab for metastatic HER2-positive breast cancer. Study results identified poor prognostic factors as older age, increased platelet-to-lymphocyte ratio (PLR), and alkaline phosphatase (ALP), while ER positivity was seen as a favorable prognostic factor for overall survival (OS), after adjusting for the presence of CNS metastasis and the presence of number of ≥ 2 distant metastatic sites. For both OS and failure-free survival (FFS), increased PLR was identified as a poor prognostic factor.

Methods

• Researchers used the Cancer Care Ontario (CCO) Registry (n = 256) and identified all HER2-positive metastatic breast cancer patients receiving trastuzumab at the Sunnybrook Odette Cancer Centre (SOCC) from 1999 to 2013.
• They selected patients with available pathology reports (n = 154) and carried out a retrospective review reporting clinical, pathologic, and laboratory features at the time of first trastuzumab therapy and survival outcomes.
• Using Cox proportional hazards regression models, adjusted for the known prognostic factors of the presence of CNS metastases and the presence of ≥ 2 distant metastatic sites, they investigated prognostic factors for OS (primary endpoint) and FFS.

Results

• In a multivariable model, after adjusting for the presence of CNS metastasis (HR 3.19, 95% CI 1.59–6.38) and the presence of ≥ 2 distant metastatic sites (HR 2.10, 95% CI 1.19–3.70), the following were identified as significant prognostic factors for OS: older age (hazard ratio [HR] 1.18/decade, 95% confidence interval [CI] 1.02–1.37]), increased PLR (HR 1.75/log-unit, 95% CI 1.25–2.46), increased serum ALP (HR 1.87/log-unit, 95% CI 1.41–2.49), and ER positivity (HR 0.63, 95% CI 0.42–0.96).
• The only prognostic factor which was found to be associated with FFS after adjusting for CNS and ≥ 2 distant metastatic sites was PLR (HR 1.54/log-unit, 95% CI 1.12–2.12).