Cancer-Associated Thrombosis: A Clinical Scoping Review of the Risk Assessment Models Across Solid Tumours and Haematological Malignancies

Cancer-associated thrombosis (CAT) is a leading cause of death in cancer patients receiving outpatient chemotherapy. The latest guidelines emphasize stratifying the patients in terms of CAT risks periodically. Multiple risk assessment models (RAMs) were developed to classify patients and guide thromboprophylaxis to high-risk patients. This study aimed to discuss and highlight different RAMs across various malignancy types with their related advantages and disadvantages. A scoping review was conducted using predefined search terms in three scientific databases, including Google Scholar, Science Direct, and PubMed. The search for studies was restricted to original research articles that reported risk assessment models published in the last thirteen years (between 2008 and 2021) to cover the most recently published evidence following the development of the principal risk assessment score in 2008. Data charting of the relevant trials, scores, advantages, and disadvantages were done iteratively considering the malignancy type. Of the initially identified 1115 studies, 39 studies with over 67,680 patients were included in the review. In solid organ malignancy, nine risk assessment scores were generated. The first and most known Khorana risk score still offers the best available risk assessment model when used for high-risk populations with a threshold of 2 and above. However, KRS has a limitation of failure to stratify low-risk patients. The COMPASS-CAT score showed the best performance in the lung carcinoma patients who have a higher prevalence of thrombosis than other malignancy subtypes. In testicular germ cell tumours, Bezan et al RAM is a validated good discriminatory RAM for this malignancy subtype. CAT in haematological malignancy seems to be under-investigated and has multiple disease-related, and treatment-related confounding factors. AL-Ani et al score performed efficiently in acute leukemia. In multiple myeloma, both SAVED and IMPEDED VTE scores showed good performance. Despite the availability of different disease-specific scores in lymphoma-related thrombosis, the standard of care needs to be redefined.