From the Guidelines
Schistocytes in cancer patients are primarily caused by microangiopathic hemolytic anemia (MAHA), which occurs when red blood cells are mechanically damaged as they pass through abnormal small blood vessels, and this condition is often associated with disseminated intravascular coagulation (DIC), cancer-associated thrombotic microangiopathy, or as a complication of chemotherapy, as reported in a study published in 2021 1.
Causes of Schistocytes in Cancer Patients
The formation of schistocytes in cancer patients can be attributed to several factors, including:
- Disseminated intravascular coagulation (DIC) due to the release of procoagulant substances by tumor cells, which activate the coagulation cascade and lead to widespread microvascular thrombi formation 1
- Cancer-associated thrombotic microangiopathy, which can cause mechanical damage to red blood cells as they pass through abnormal small blood vessels 1
- Chemotherapy, which can cause endothelial damage and contribute to schistocyte formation, with certain agents like mitomycin C, gemcitabine, and cisplatin being more commonly associated with this complication 1
- Bone marrow infiltration by cancer cells, which can disrupt normal hematopoiesis and affect red cell membrane integrity 1
- Direct invasion of blood vessels by tumor cells, particularly mucin-producing adenocarcinomas, creating physical obstructions that fragment red blood cells 1
Management and Treatment
Treatment of schistocytes in cancer patients focuses on addressing the underlying cancer with appropriate chemotherapy regimens, managing DIC with supportive care, and sometimes using plasmapheresis in severe cases of thrombotic microangiopathy, as recommended in a study published in 2018 1.
- Monitoring complete blood counts regularly during cancer treatment is essential for early detection of this complication
- Management of immune-related adverse events, such as schistocytosis, may involve the use of eculizumab therapy or red blood transfusions, depending on the severity of the condition 1
From the Research
Causes of Schistocyte in Cancer Patients
- Schistocytes, also known as fragmented red blood cells, can be a sign of thrombotic microangiopathy (TMA) in cancer patients 2, 3, 4, 5.
- TMA in cancer patients can be caused by several mechanisms, including:
- These causes of TMA must be distinguished from thrombotic thrombocytopenic purpura (TTP), which results from a severe deficiency of ADAMTS13 and is the most common cause of TMA among adults without cancer 2, 6.
Chemotherapy-Associated TMA
- Chemotherapy-associated TMA is a rare but often devastating complication of cancer treatment 3, 4.
- The management of chemotherapy-associated TMA remains less clear, and treatment generally involves withdrawal of the offending agent and supportive care targeting blood pressure and proteinuria reduction 4.
- Immunosuppression and therapeutic plasma exchange have not shown clear benefit, but the terminal complement inhibitor, eculizumab, has shown promising results in some cases of chemotherapy-associated TMA 4.
Diagnosis and Management
- Thorough clinical and laboratory evaluation is essential to distinguish various TMAs and arrive at an accurate diagnosis, which is key for appropriate management 2, 6.
- Plasma exchange is ineffective in the management of cancer-associated TMA, and the challenge of cancer-associated TMA is furthered by the fact that there is a lack of standard diagnostic criteria and limited therapeutic options 5.