The passing of Catherine O’Hara on January 30, 2026, left an undeniable void in the world of entertainment. For decades, O’Hara brought joy to audiences through her sharp wit and unforgettable performances — from SCTV and Beetlejuice to the eccentric elegance of Moira Rose in Schitt’s Creek. Her legacy is one of laughter, brilliance, and originality.

Confirmation that O’Hara died from a pulmonary embolism (blood clot in the lungs) related to rectal cancer adds a sobering dimension to this loss. Beyond mourning an extraordinary artist, her sudden passing underscores an urgent but often overlooked medical reality: blood clots are one of the most serious and preventable complications of cancer.

At the National Blood Clot Alliance (NBCA), we believe awareness is power — and awareness can save lives.

The Dangerous Link Between Cancer and Blood Clots

For many families, a cancer diagnosis feels like the ultimate battle. The focus is understandably on fighting the disease itself. But there is a secondary danger that often goes unmentioned — blood clots.

Many people are unaware that cancer significantly increases the risk of developing blood clots, medically known as venous thromboembolism (VTE). VTE includes:

• Deep Vein Thrombosis (DVT) — a clot typically in the leg or arm
• Pulmonary Embolism (PE) — a clot that travels to the lungs and can be fatal

The connection between cancer and blood clots is not rare — and it is not minor.

In fact, blood clots are the second leading cause of death in people with cancer, second only to the cancer itself.

Up to 1 in 5 individuals with cancer will develop a blood clot at some point during treatment or recovery. For many, symptoms are subtle or mistaken for side effects of therapy — allowing a preventable complication to become life-threatening.

Why does cancer increase clot risk?

The relationship is complex, but several factors contribute:

• Cancer cells can release substances that make blood more likely to clot.
• Chemotherapy and certain targeted therapies can increase clotting risk.
• Surgery, hospitalization, and reduced mobility further elevate risk.
• Central lines and ports used for treatment can trigger clot formation.

For many patients, symptoms of a blood clot — such as fatigue, leg discomfort, or shortness of breath — may be mistaken for side effects of treatment. That delay can be dangerous.

A Public Health Crisis Hiding in Plain Sight

Each year in the United States:

• Approximately 100,000 people die from pulmonary embolism
• An estimated 900,000 Americans develop a blood clot

While cancer patients face higher risk, blood clots can affect anyone — regardless of age, fitness level, or health history.

Despite the scope of the problem, awareness remains alarmingly low.

Recent research conducted in partnership with NBCA found that many patients with cancer are unaware of their increased risk for blood clots — and most report that they have never discussed prevention with their healthcare team, even though they would be open to doing so.

Closing this gap in awareness and conversation is a critical step toward reducing preventable harm. [PMID 41496891]

Many Cancer-Associated Blood Clots Are Preventable

Not every blood clot can be prevented. But many can.

Through individualized risk assessment and appropriate use of preventive strategies — including blood-thinning medications in certain high-risk situations — the likelihood of life-threatening clots can be reduced.

However, prevention remains underutilized for several reasons:

• Concerns about bleeding risk
• Lack of standardized risk assessment conversations
• Limited patient awareness

Improving awareness — among both patients and clinicians — is critical to reducing preventable harm.

What You Can Do

Prevention begins with conversation.

You can:

• Talk with your healthcare team about your personal risk — especially during cancer treatment, illness, hospitalization, or after surgery.
• Ask whether preventive medications or other protective measures are appropriate.
• Stay active when possible and maintain hydration.
• Seek immediate care if symptoms develop.

Recognizing those symptoms — and understanding when risk is elevated — can make a life-saving difference.

Know the Signs, Understand the Risk, and Take Steps to Prevent Blood Clots

Recognizing the warning signs of a blood clot is critical — but awareness goes beyond symptoms alone.

It is equally important to understand when risk may be higher and what can be done to reduce it.

Blood clots can occur in many situations, including:

• During or after hospitalization
• After surgery
• During periods of reduced mobility
• During pregnancy or the postpartum period
• In the presence of certain medical conditions

Cancer is one of the strongest risk factors for blood clots — particularly with certain cancer types, more advanced stages of disease, and during active treatment.

Understanding these risks allows patients and caregivers to act early and seek care before complications become serious.

Warning Signs of a Blood Clot

Deep Vein Thrombosis (DVT)

• Swelling, usually in one leg or arm
• Pain or tenderness not caused by injury
• Warmth, redness, or discoloration

Pulmonary Embolism (PE)

• Sudden shortness of breath
• Sharp chest pain that worsens with deep breaths
• Rapid heart rate
• Lightheadedness
• Coughing, sometimes with blood

A pulmonary embolism is a medical emergency. Seek immediate care if symptoms develop.

Honoring Catherine O’Hara Through Awareness

Catherine O’Hara’s legacy is one of laughter, creativity, and unforgettable characters. We honor that legacy by ensuring her story becomes part of a broader conversation — one that empowers patients and families with knowledge.

Blood clots do not have to be a silent threat.

March is Blood Clot Awareness Month, the perfect time to arm yourself with the knowledge that saves lives. By understanding risk, recognizing symptoms, and starting prevention conversations, lives can be saved.

Take Action

Learn the signs. Understand your risk. Start the conversation.

Explore StopTheClot.org to access resources on:

• Cancer-associated thrombosis (CAT)
• Blood clot signs and symptoms
• Risk factors and prevention strategies
• Questions to ask your healthcare provider

Awareness is the first step toward prevention.

About the Author

Dr. Rushad Patell is a hematologist at Beth Israel Deaconess Medical Center, (BIDMC) and an Assistant Professor of Medicine at Harvard Medical School in Boston, MA. where he treats patients with hematologic conditions, with specific expertise in cancer associated thrombosis.  He currently serves as the Associate Program Director for the combined hematology oncology fellowship program at BIDMC, director of clinical and translational research in Benign Hematology at BIDMC and is also the Co-Chair of the National Blood Clot Alliance Council of Emerging Researchers in Thrombosis (CERT).  Dr. Patell is a longtime admirer of Catherine O’Hara’s work and is deeply saddened by her passing.

Additional Resources

Cancer and blood clots information

Cancer & Blood Clots: What You Need To Know

Stop the Clot Spread the Word: Cancer