The incidence of thrombocytopenia in adult patients receiving chemotherapy for solid tumors or hematologic malignancies.

OBJECTIVES

To estimate the risk of thrombocytopenia in various cancers and chemotherapy regimens.

METHODS

Structured patient-level data from the Flatiron Health Electronic Health Record database were used to identify adult patients who received chemotherapy for a solid tumor or hematologic malignancy from 2012 to 2017. Three-month cumulative incidence of thrombocytopenia was assessed based on platelet counts, overall and by grade of thrombocytopenia. Co-occurrence of anemia, neutropenia, and leukopenia was evaluated.

RESULTS

Of 15,521 patients with solid tumors, 13% had thrombocytopenia within 3 months (platelet count < 100 × 10 /L); 4% had grade 3 (25 to < 50 × 10 /L), and 2% grade 4 (<25 × 10 /L) thrombocytopenia. Of 2537 patients with hematologic malignancies, 28% had any thrombocytopenia, 16% with grade 3, and 12% with grade 4. Among patients with thrombocytopenia, it occurred without another cytopenia in 18% of solid tumors and 7% of hematologic malignancies.

CONCLUSIONS

In a large, US-representative sample of patients undergoing chemotherapy in clinical practice, thrombocytopenia incidence varied across tumor and regimen types. Despite recommendations to alter chemotherapy to avoid severe thrombocytopenia, 4% of patients with solid tumors and 16% with hematologic malignancies experienced grade 3 thrombocytopenia. Prediction and prevention of thrombocytopenia may help oncologists avoid dose modifications and their adverse effects on survival.