2026 American Academy of Neurology Abstract Website

Objective:

To highlight that tumour size is not a reliable predictor of thrombotic risk, and that even small-volume cancers can pose a significantly higher risk of thrombosis than some large-volume cancers.

Background:

Cancer-associated thrombosis (CAT) is an important, but often underrecognized cause of recurrent stroke.1 Some risk factors such as age and sex are non-modifiable, but others, including tumor biology and patient comorbidities, can be identified and managed proactively to reduce thrombotic risk.2 Traditionally, larger tumors were considered to confer higher thrombotic risk. Additional contributors include cancer stage, primary tumor site (e.g., stomach, kidney, and pancreas), and histological subtype, with adenocarcinomas carrying greater risk than squamous cell carcinomas.2

Although tumor burden is often emphasized as the primary determinant of thrombotic risk, emerging evidence suggests that tumor biology, such as procoagulant molecule expression and inflammatory signaling, may be equally, if not more, important.3 We describe two patients with small tumors who nonentheless experienced recurrent strokes.

Design/Methods:

Results:

Two patients with early-stage cancers (1.3 cm non–small cell lung cancer and 1.6cm renal cell carcinoma) developed recurrent deep venous thrombosis and embolic strokes despite standard anticoagulation.

Conclusions:

Tumor size alone may underestimate thrombosis risk. These cases of early-stage NSCLC and RCC with recurrent stroke and DVT underscore the importance of considering tumor biology, prothrombotic signaling, and host inflammatory response, even in small tumors. Clinicians should maintain a high index of suspicion for hypercoagulable states in patients with small tumors and otherwise unexplained thromboses.