BURDEN OF THROMBOCYTOPENIA IN CANCER PATIENTS UNDERGOING CHEMOTHERAPY, 2000-2007

OBJECTIVES: Along with neutropenia and anemia, thrombocytopenia is one of the most common hematological complications of cancer treatment. Prolonged/severe thrombocytopenia increases the risk of bleeding.The goal of this study was to evaluate the epidemiology of thrombocytopenia among cancer patients on chemotherapy. METHODS: Data were collected between 2000–2007 from a large electronic medical records database in 18 outpatient oncology clinics throughout the US. Adult patients with NSCLC, breast, ovarian, H&N, and colorectal cancers were of interest. Chemotherapy regimens were grouped into platinum-, anthracycline-, gemcitabine-, and taxane- based. Thrombocytopenia (<150,000 µl) prevalence was examined by tumor and regimen type. RESULTS: A total of 47,159 patients [mean age 61, male 42%] 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. Prevalence of post-chemo thrombocytopenia was highest among gemcitabine treated patients (64.2%), followed by platinum (55.5%), and lowest with taxane-based regimens (21.9%). Most of the patients across all treatment regimen groups presented with thrombocytopenia (grade 1). Eleven percent of patients on platinum and gemcitabine regimens, 2% in taxane-treated patients, and 5% in anthracycline-treated patients had PC<50x109/L (grade 3–4). Patients with NSCLC and ovarian cancer had the highest incidence of thrombocytopenia. A substantial proportion of patients, 30% developed both anemia and thrombocytopenia after chemotherapy start. More than 90% of patients with thrombocytopenia grade 1–3 also had anemia grade 1 or 2. Twenty percent of those with grade 4 thrombocytopenia 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. Platelet transfusions were rare (<5% of all chemotherapy-treated patients).  CONCLUSIONS:   Thrombocytopenia was common in this large cohort of cancer patients on chemotherapy. A substantial proportion of patients developed both anemia and thrombocytopenia.