Circulating small-sized endothelial microparticles as predictors of clinical outcome after chemotherapy for breast cancer: an exploratory analysis

PURPOSE

Therapeutic exploitation of angiogenesis in breast cancer has been limited by the lack of reliable biomarkers. Circulating small-sized endothelial microparticles (sEMP) are likely to play a significant role as messengers of angiogenesis. Higher levels of EMP have been observed in cancer patients, but their prognostic value in breast cancer is unknown. Our aim was to determine the value of circulating sEMP as a marker of response to chemotherapy in breast cancer.

METHODS

We included patients with breast cancer treated with neoadjuvant or first-line chemotherapy. Baseline and post-treatment circulating sEMP (CD144+) were quantified using a flow cytometer approach specifically designed for analysis of small-sized particles (0.1-0.5 μm). Small-sized EMP response was defined as a post-treatment decrease of sEMP larger than the median decrease of sEMP after chemotherapy. Baseline and post-chemotherapy VEGFA levels were determined with ELISA.

RESULTS

Forty-four breast cancer patients were included (19 with metastatic and 25 with locally advanced disease). Median levels of sEMP decreased after chemotherapy (P = 0.005). Response to chemotherapy showed a non-significant trend to associate with sEMP response (P = 0.056). A sEMP response was observed in 51% of patients and was associated with better overall survival (HR 0.18; 95% CI 0.04-0.87; P = 0.02) and progression free survival (HR 0.30; 95% CI 0.09-0.99; P = 0.04) in the group of women with metastatic disease. Post-chemotherapy decrease of VEGFA levels was not associated with breast cancer prognosis.

CONCLUSIONS

Our results did not support sEMP as a marker of response to chemotherapy. However, our exploratory analysis suggests that in patients with metastatic breast cancer, the decrease of sEMP levels after chemotherapy is associated with better overall and disease free survival and might be superior to VEGFA levels as an angiogenesis-related prognostic marker.

Delayed recovery and increased severity of Paclitaxel-induced peripheral neuropathy in patients with diabetes

PURPOSE

Although diabetes mellitus (DM) is recognized as a risk factor for chemotherapy-induced neurotoxicity, its true impact on intensity and time course of peripheral neuropathy is still unclear. The goal was to analyze the relevance of preexisting DM to weekly paclitaxel-induced peripheral neuropathy (PIPN).

METHODS

We performed a retrospective case-control study (1:2) including a total of 129 patients with breast cancer (43 with DM and 86 controls) treated with single-agent weekly paclitaxel (wP).

RESULTS

Compared with controls, patients with DM treated with wP experienced PIPN more frequently (74.4% vs 58.4%; P=.016) and with higher severity (grade 2-3: 51.2% vs 27.7%; P=.014). A significant delay in PIPN resolution was observed in women with DM (P=.001) and, in a multivariate analysis, DM was the only independent predictor for delayed recovery (hazard ratio [HR], 0.16; 95% CI, 0.05-0.55; P=.003). After 2 years, 68.7% of patients with DM (vs 29.2% of women without DM) still experienced PIPN, which was functionally significant (grade 2-3) in 18.2%.

CONCLUSIONS

Significantly more dose delays and reductions because of PIPN occurred in patients with DM. Preexisting DM associates with long-lasting significant PIPN in patients treated with wP. Benefits and risks of long-term significant PIPN should be carefully balanced in patients with DM before starting wP chemotherapy.