Predictors for doxorubicin-induced hematological toxicity and its association with outcome in advanced soft tissue sarcoma patients; a retrospective analysis of the EORTC-soft tissue and bone sarcoma group database

INTRODUCTION: As both anti-tumour effects and toxicity are thought to be dose-dependent, patients with the greatest toxicity may also have the best outcome. We assessed whether severity of doxorubicin-induced hematological toxicity is associated with outcome in advanced soft tissue sarcoma (STS) patients. In addition, risk factors for hematological toxicity were explored.

METHODS: Worst haematological toxicities (anaemia, leukopenia, neutropenia and thrombocytopenia) seen during treatment were scored according to CTCAE toxicity score. Differences in overall survival (OS), progression free survival (PFS) and response rate (RR) between patients with or without high haematological toxicity (grades 0-2 vs. 3-4) were assessed using conventional statistical tests. Associations between baseline characteristics and hematological toxicity were established using logistic multivariate regression.

RESULTS: In 557 patients eligible for this analysis, 47.2% of the patients received at least six cycles of treatment; 45% stopped treatment early due to progression, 3% because of toxicity. Relative dose intensity (RDI) was constant over the cycles. OS, PFS, and RR did not differ between patients with grade 3/4 toxicity during treatment versus those with grade 1/2. Risk factors for grade 3/4 haematological toxicity, in particular neutropenia, were age above 60 years, low BMI, and female gender.

CONCLUSION: In this large series, risk factors for haematological toxicity in STS patients receiving doxorubicin monotherapy were revealed. The finding that there was no association between outcome and haematological toxicity during doxorubicin treatment may be useful to reassure advanced STS patients that failure to experience haematological toxicity during treatment does not equate to under-treatment.