Real-World Rates and Management of Thrombocytopenia Due to Cancer Treatment in Advanced/Metastatic Female Genitourinary Malignancies
Authors: Ransom Joshua F , Galaznik Aaron , Rusli Emelly , Lempernesse Bruno , Berger Marc 
Published: November 2019

OBJECTIVES
Thrombocytopenia is a common, potentially treatment-limiting hematologic side effect in cancer treatment (Kuter DJ, 2018). This is particularly true for female genitourinary (fGU) cancers, such as ovarian and endometrial, where treatment involves agents such as platinum-based agents, taxanes, PARP inhibitors, and gemcitabine (Lord R et al., 2018; Berek JS et al., 2018; Cassidy CA et al., 2001; Ten Berg MJ et al., 2001; Mahner S., 2015). Evidence has shown that dose reduction can be an effective way to address thrombocytopenia and avoid discontinuation of treatment (Lord R et al., 2018; Berek JS et al., 2018). In this study, we explore the use of RWD to understand real-world rates of thrombocytopenia in fGU cancer, including rates of occurrence, management and impacts on chemotherapy treatment, dose reduction, and discontinuation.
METHODS
Analyses were conducted on nationally representative insurance claims database and Electronic Medical Records (EMR). Inclusion criteria of adult fGU cancer patients with prior exposures to gemcitabine, platinum-based agents, taxanes, or PARP inhibitor with 1-month continuous enrollment (or activity, for EMR) were applied. Thrombocytopenia post-treatment exposure was identified using ICD codes. Baseline descriptive characteristics and subsequent dosing changes were assessed. Results were also stratified for the top 2 fGU malignancies present in the data, ovarian and endometrial cancer (approximately two-fifths and one-third respectively). Factors associated with thrombocytopenia were assessed using logistic regression modeling and ensemble predictive model approaches (e.g., XG Boost). Covariates for regression modeling included patient demographics, pre-existing medical conditions, drug exposures and lab test procedures. Model performance was assessed using Receiver-Operating Characteristic (ROC) scores).
RESULTS
Thrombocytopenia incidence ranged from 10-15%, with approximately 6% of cases diagnosed within the first 60 days of therapy. Early onset of thrombocytopenia (within 30 days of initiating therapy) occurred in less than 5% of patients and increased to 13% after more than 90 days. A significant proportion of patients with thrombocytopenia showed evidence of treatment discontinuation, with relatively few showing evidence of dose reduction in chemotherapy. Of patients with TCP, up to 15% of patients were prescribed corticosteroids and less than 10% of patients required platelet transfusion. ROC scores for ensemble model approaches were on the order of 85-90%. Factors associated with development of TCP included age, history of arterial disease, and concomitant GI malignancy.
CONCLUSION
Thrombocytopenia is a common condition in ovarian and endometrial cancer, leading to treatment discontinuation in a high proportion of patients. Given relatively low rates of chemotherapy dose titration in TCP patients, there is an opportunity to improve management of this hematologic complication and enable patients to remain on chemotherapy. Predictive model findings, while preliminary, also suggest opportunity to proactively identify patients with high risk of developing TCP, thereby facilitating earlier identification and pre-emptive treatment modification.

Disclosures
Ransom: Medidata Solutions: Employment. Galaznik:Medidata Solutions: Employment. Rusli:Medidata Solutions: Employment. Lempernesse:Medidata Solutions: Employment. Berger:Medidata Solutions: Consultancy.