Burden of Thrombocytopenia in Cancer Patients Undergoing Chemotherapy: a Retrospective Database Analysis

Background. Along with anemia and neutropenia, thrombocytopenia is a common hematological adverse effect of chemotherapy. Prolonged and severe thrombocytopenia increases the risk of bleeding episodes. The goal of this study was to evaluate the epidemiology of thrombocytopenia among cancer patients on chemotherapy.

Methods. Pooled data over the period 2000–07 from a large electronic database of 15 community and 3 hospital-based outpatient oncology clinics in the US was analyzed. For this analysis, adult patients with a cancer diagnosis were grouped as: lung, breast, ovarian, H&N, colorectal, other solid cancers, hematologic and mixed cancers. Chemotherapies used were grouped into platinum, anthracycline, gemcitabine, taxane-based and other regimens. Incidence of Thrombocytopenia (defined as <150,000/μl) was examined by tumor and regimen.

Results. 47,159 patients [mean age 61, male 42%] who met inclusion criteria and 75,243 chemotherapy regimens were analyzed. Breast cancer patients constituted 19.5%, followed by NSCLC (14.9%), colorectal (11.9%), ovarian (3.1%), and H&N (2.5%). Platinum-based regimens accounted for 27.8% of all regimens. The incidence of post-chemo thrombocytopenia was highest among gemcitabine treated patients (64.2%), followed by platinum (55.5%). The lowest incidence was with taxane-based regimens (21.9%). Grade 3–4 (<50×10⁹/L) thrombocytopenia was seen in 11% of patients on platinum or gemcitabine regimens, 2% of taxane-treated patients, and 5% of anthracycline-treated patients. Patients with NSCLC and ovarian cancer experienced highest incidence of thrombocytopenia. Thirty percent of patients (14,103) developed both anemia and thrombocytopenia during their chemotherapy. More than 90% of patients with thrombocytopenia grade 1–3 also had concomitant anemia grade 1 or 2. Twenty percent of patients with grade 4 thrombocytopenia also presented with anemia grade 3–4. Of these, 16.7% had NSCLC, 16.2% were breast cancer patients, and 9.1% were colorectal cancer patients. However, platelet transfusions were relatively rare (<5%) in these chemotherapy-treated patients.

Conclusions. Thrombocytopenia was relatively common in this large cohort of cancer patients undergoing chemotherapy. A substantial proportion of patients with thrombocytopenia also had anemia.