Doctor, I have cancer and a small pulmonary embolism. Can I be treated with anticoagulation for a short period of time?

In people with cancer and acute small (low-risk) pulmonary embolism (PE), treatment with rivaroxaban (Xarelto®) for 18 months reduced the risk of another blood clot (recurrent venous thromboembolism [VTE]) more than a shorter treatment course of 6 months.

The length of treatment needed for your PE will be decided by you and your doctor by comparing your risk of having another clot with your risk of bleeding while taking anticoagulants.

Study highlights

About 6 out of every 100 people with cancer and low-risk PE who received 18 months of rivaroxaban treatment developed recurrent VTE compared to 19 out of 100 people who received 6 months of rivaroxaban treatment.

The risk of major bleeding was not different for people who received 18 months of rivaroxoban treatment compared with those who received 6 months of rivaroxaban treatment.

This study was limited to Japan and was stopped early so it is possible the results would be different in another study.

What's the issue?

Understanding the problem

Cancer increases your risk of developing a blood clot. Pulmonary embolism may be found on routine imaging scans for evaluation of cancer in people who do not have any symptoms of PE, such as chest pain or shortness of breath. We do not know if people with a small PE and no symptoms should be treated for the same length of time as people with cancer who have larger PE or who are experiencing symptoms.

This study aimed to determine if treatment with anticoagulants for 18 months would be better than 6 months for people with cancer and a new diagnosis of low-risk PE.

The study

Who? The study included 179 people who had cancer and acute low-risk PE as determined by a simplified Pulmonary Embolism Severity Index (sPESI) of 1. The sPESI score considers age, history of cancer, history of heart or lung disease, heart rate, blood pressure, and oxygen saturation (amount of oxygen detected in the blood by using a probe clipped to a finger).

What? The study compared 18 months versus 6 months of treatment with rivaroxaban.

Longer Duration of Anticoagulation		Shorter Duration of Anticoagulation
Rivaroxaban 15 mg twice daily for the first 3 weeks followed by 15 mg once daily afterwards. (Note that this is the standard rivaroxaban dosing regimen for the treatment of PE in Japan, where the study was conducted.) Patients were treated with rivaroxaban for 18 months starting from the date of diagnosis of PE until the end of the study.		Rivaroxaban 15 mg twice daily for the first 3 weeks followed by 15 mg once daily afterwards. (Note that this is the standard rivaroxaban dosing regimen for the treatment of PE in Japan, where the study was conducted.) Patients were treated with rivaroxaban for 6 months starting from the date of diagnosis of PE.

Longer Duration of Anticoagulation

Shorter Duration of Anticoagulation

Rivaroxaban 15 mg twice daily for the first 3 weeks followed by 15 mg once daily afterwards. (Note that this is the standard rivaroxaban dosing regimen for the treatment of PE in Japan, where the study was conducted.)

Patients were treated with rivaroxaban for 18 months starting from the date of diagnosis of PE until the end of the study.

Patients were treated with rivaroxaban for 6 months starting from the date of diagnosis of PE.

Summary of findings

Treatment with rivaroxaban for 18 months vs rivaroxaban for 6 months in people who have cancer and acute low-risk PE.

Outcomes	Rate of events with rivaroxaban treatment for 18 months	Rate of events with rivaroxaban treatment for 6 months	Results
Recurrent VTE	6 out of 100 people	19 out of 100 people	About 13 fewer people out of 100 had recurrent VTE after completing 18 months of rivaroxaban treatment compared to those who completed 6 months of rivaroxaban treatment
Major bleeding	8 out of 100 people	6 out of 100 people	No difference*

*Although the rates for the 2 groups look different, the differences were not statistically significant—this means that the difference could simply be due to chance rather than due to the different treatments.

This Evidence Summary is based on the following article:

Yamashita Y, Morimoto T, Muraoka N, et al. Rivaroxaban for 18 Months Versus 6 Months in Patients With Cancer and Acute Low-Risk Pulmonary Embolism: An Open-Label, Multicenter, Randomized Clinical Trial (ONCO PE Trial). Circulation. 2024 Nov 18. doi: 10.1161/CIRCULATIONAHA.124.072758. PubMed

Author Details

Sarah Ge, BHSc, MD

Sarah is a PGY3 internal medicine resident at McMaster University and will be pursuing Hematology training at the University of Toronto where she also completed her medical degree. Her interests include hematology as well as medical education and global health research.

Author Details

Siraj Mithoowani, MD, MHPE, FRCPC, FACP

Siraj Mithoowani is an Assistant Professor in the Department of Medicine, McMaster University, and is a clinical hematologist at St. Joseph's Healthcare, Hamilton. He specializes in the care of non-malignant and thrombotic blood disorders. His research interests are in venous thromboembolism and postgraduate medical education.

Published: Thursday, March 27, 2025

Please note that the information contained herein is not to be interpreted as an alternative to medical advice from a professional healthcare provider. If you have any questions about any medical matter, you should consult your professional healthcare providers, and should never delay seeking medical advice, disregard medical advice or discontinue medication based on information provided here.

This Evidence Summary was printed from the CLOT+ website on 2025/05/04.

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