What types of cancer affect platelets?

Types of Cancer That Affect Platelets

Hematologic malignancies are the primary cancers that directly affect platelets, with acute myeloid leukemia (AML), other acute leukemias, myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPNs), and acute promyelocytic leukemia being the most clinically significant. 1

Hematologic Malignancies with Direct Platelet Impact

Acute Leukemias

• Acute myeloid leukemia (AML) is the most extensively studied cancer affecting platelets, causing severe thrombocytopenia through bone marrow infiltration and impaired platelet production 1
• Acute lymphocytic leukemia (ALL) similarly causes thrombocytopenia requiring frequent platelet transfusion support during induction therapy 1
• Acute promyelocytic leukemia (APL) is particularly dangerous, causing both severe thrombocytopenia and disseminated intravascular coagulation (DIC) with life-threatening bleeding risk 1, 2, 3

Myelodysplastic Syndromes (MDS)

• MDS causes chronic, stable, severe thrombocytopenia through ineffective hematopoiesis 1
• Patients with MDS may maintain stable platelet counts for extended periods despite severe thrombocytopenia, often not requiring prophylactic transfusions unless actively bleeding 1
• Critical warning: Romiplostim (Nplate) is contraindicated in MDS as it may accelerate progression to acute myeloid leukemia with increased mortality 4

Myeloproliferative Neoplasms (MPNs)

• MPNs with JAK2V617F, CALR, or MPL mutations cause both quantitative and qualitative platelet abnormalities 5
• These disorders paradoxically increase thrombotic risk despite abnormal platelet function, with patients experiencing both arterial and venous thrombosis 5, 6
• Platelet counts between 6-80 × 10⁹/L are poor predictors of bleeding risk in MPNs because platelet function is severely impaired regardless of number 7

Solid Tumors with Platelet Effects

High-Risk Solid Tumors

• Bladder tumors require higher prophylactic platelet transfusion thresholds (20,000/μL vs 10,000/μL) due to increased bleeding risk from necrotic tumor tissue 1
• Metastatic prostate cancer causes bleeding-predominant DIC with severe thrombocytopenia and consumptive coagulopathy 2, 3
• Pancreatic adenocarcinoma causes thrombosis-predominant DIC with platelet activation and increased thrombotic complications 2, 3
• Other adenocarcinomas (gastric, lung, ovarian) promote platelet activation and cancer-associated thrombosis through tumor-platelet interactions 8, 6, 9

Mechanisms of Platelet Dysfunction in Solid Tumors

• Solid tumors cause thrombocytopenia through chemotherapy-induced bone marrow suppression rather than direct marrow infiltration 1
• Tumor cells activate platelets through direct contact and release of procoagulant factors, promoting both thrombosis and metastasis 8, 6, 9
• Necrotic tumors increase local bleeding risk even with adequate platelet counts 1

Cancer-Associated Thrombocytopenia Patterns

Treatment-Related Thrombocytopenia

• Chemotherapy for hematologic malignancies causes predictable, severe thrombocytopenia requiring prophylactic transfusion at <10,000/μL (or <20,000/μL with risk factors) 1
• Hematopoietic stem cell transplantation (both autologous and allogeneic) causes profound thrombocytopenia, though peripheral blood stem cells reduce duration compared to bone marrow transplants 1
• Solid tumor chemotherapy causes less severe thrombocytopenia with lower transfusion requirements than hematologic malignancies 1

DIC-Associated Thrombocytopenia

• A 30% or greater drop in platelet count is diagnostic of subclinical DIC even when absolute values remain normal 2, 3
• APL, metastatic prostate cancer, and mucin-secreting adenocarcinomas most commonly cause bleeding-predominant DIC 2, 3
• Pancreatic cancer and other adenocarcinomas cause thrombosis-predominant DIC with platelet consumption 2, 3

Clinical Implications by Cancer Type

Cancers Requiring Leukoreduced Products

• AML patients should receive leukoreduced platelets and RBCs from diagnosis to prevent alloimmunization and platelet refractoriness 1
• Other acute leukemias likely benefit from leukoreduction though randomized trials are lacking 1
• Patients requiring prolonged, repetitive transfusion support (chronic leukemias, MDS) benefit from leukoreduction 1

Cancers with Increased Bleeding Risk

• APL requires aggressive platelet support maintaining counts >50,000/μL due to concurrent DIC 1, 2, 3
• Bladder tumors and necrotic solid tumors require prophylactic transfusion at 20,000/μL rather than 10,000/μL 1
• Liver metastases causing hepatic dysfunction compound thrombocytopenia with coagulopathy 3

Cancers with Increased Thrombotic Risk

• MPNs cause paradoxical thrombosis despite platelet dysfunction, requiring anticoagulation consideration 5, 6
• Pancreatic and other adenocarcinomas activate platelets promoting venous thromboembolism (VTE) 8, 6, 9
• Thrombocytosis in solid tumors is a predictive biomarker for VTE risk 8, 9