RIP, Catherine O'Hara, Age 71: On Cancer and Pulmonary Embolisms
Pulmonary embolisms are fairly common for certain types of cancer, and some history with Armand Trousseau
When I heard Catherine O’Hara died “after a short illness” at age 71, I figured it was from cancer.
It was.
.jpg){kind=link}
9 Feb 2026, People: Catherine O’Hara’s Cause of Death Confirmed, Comedy Legend Privately Faced Rectal Cancer: Medical Examiner
Catherine O’Hara‘s official cause of death has been determined.
The actress, known for her roles in Schitt’s Creek and Home Alone, died at 71 on Friday, Jan. 30. Her rep confirmed to PEOPLE at the time that she’d died “after a brief illness” but did not provide further details.
On Monday, Feb. 9, the Los Angeles County Medical Examiner’s Office confirmed that O’Hara died after suffering from a pulmonary embolism, according to a death certificate obtained by PEOPLE. Rectal cancer was listed as the underlying cause of the embolism.
According to this article: 9 Feb 2026, sfgate: Catherine O’Hara died from a pulmonary embolism. Cancer was the underlying cause
A Los Angeles County death certificate issued Monday lists the pulmonary embolism, which occurs when a blood clot blocks an artery in the lungs, as the immediate cause of the actor's Jan. 30 death at age 71. Rectal cancer was the long-term cause.
The oncologist who signed off on the certificate indicated that he had been treating O'Hara since March of last year, and last saw her on Jan. 27. She died at a hospital in Santa Monica, California.
Pulmonary embolisms are essentially blood clots in your lungs.
My late husband Stuart probably died due to pulmonary embolism, caused by his prostate cancer. Blood clots had been proliferating through his body, and they had imaged several clots in his lungs. He was regularly administering injectable anticoagulants for the last month of his life. But it could do only so much — the cancer was winning at that point.
Some Medical Information on Cancer and Pulmonary Embolisms
Pulmonary embolisms are more common with some types and some stages of cancer.
University of Texas, MD Anderson Cancer Center: Cancer and Pulmonary Embolism Development
A pulmonary embolism (PE) is a blood clot (or thrombus) that travels from the leg, pelvis or arm into the pulmonary artery and blocks blood delivery to the lungs. Among non-hospitalized cancer patients being treated with chemotherapy, approximately 3% of deaths are caused by PE. Among hospitalized cancer patients, up to 10% of deaths are caused by PE.
Pulmonary embolism causes
A pulmonary embolism usually starts as a blood clot in the leg or pelvis, where the clot is called a deep vein thrombosis (DVT). If a piece of the clot breaks off from the vein and travels (embolizes), through the circulatory system to the pulmonary artery, it can block the supply of blood to the lungs. At that point, it is called a pulmonary embolism.
There are many things that lead to the formation of a deep vein thrombosis/pulmonary embolism in cancer patients. Some types of cancer are more likely to cause these clots, including:
brain cancer
gynecological cancers
The risk of clotting increases as the cancer grows and spreads in the body.
We didn’t see the clots for Stu until near the end.
28 May 2025, Journal of Clinical Oncology: Pulmonary embolism in cancer patients: Clinical insights and outcomes from a community hospital.
Abstract: [I added some emphasis]
Background: Pulmonary embolism (PE) is a leading cause of death in cancer patients, driven by hypercoagulability, immobility, and cancer therapies. Cancer increases the risk of venous thromboembolism (VTE) by up to 7-fold, with certain malignancies, such as gastrointestinal, pancreatic, and lung cancers, carrying the highest risk. PE in cancer patients often presents atypically, with a high rate of incidental diagnoses and significant mortality and bleeding risks. This study evaluates the clinical presentation, characteristics and outcomes of PE in cancer versus non-cancer patients in a community hospital setting.
Methods: A single centre retrospective cohort study was conducted on patients diagnosed with PE from 2018 to 2023 at a community hospital in Northern Illinois. Patient demographics, clinical presentation, PE characteristics, and outcomes were compared between cancer and non-cancer groups. Cancer-specific mortality at 30 days and 1 year was analyzed. Statistical analyses included chi-square and t-tests.
Results: Among 301 patients, 69 (22.9%) had active cancer, with lung (24%), gastrointestinal (18%), and breast (14%) cancers being the most common. Cancer patients were older (68 vs. 60 years), predominantly female (57% vs. 48%), and more likely to smoke (50.7% vs. 39.2%). Shortness of breath was the main presenting symptom in both groups, but cancer patients were more likely to have incidental PE (14.4% vs. 8.1%, p = 0.18) and syncope (11.5% vs. 6%, p = 0.1), and less likely to report chest pain (5.7% vs. 14.6%, p = 0.08), though none of these differences were statistically significant. Right heart strain (20.2% vs. 32%, p = 0.08) and saddle PE (1% vs. 5%, p = 0.3) were less common in cancer patients. Bleeding complications were significantly higher in cancer patients (15.9% vs. 6.8%, p = 0.02) along with in-hospital mortality (17.3% vs. 7.3%, p = 0.02), though many deaths were associated with advanced cancer or sepsis rather than PE itself. ICU admissions (33% vs. 34.4%) and recurrent VTE (4% vs. 3.8%) were similar. Hospice involvement occurred in 10% of cancer patients, mostly after intubation and prolonged hospital stays. Thirty-day mortality in cancer patients was 14.5%, primarily driven by sepsis secondary to pneumonia and urine infections. No deaths were linked to recurrent PE or bleeding. One-year mortality was 4.3% and included bleeding, recurrent PE, and cancer-related death.
Conclusions: Cancer-associated PE increases in-hospital mortality, yet early recognition and treatment can result in stable long-term outcomes, especially in early stages of cancer. Select patients in ICU might benefit from early palliative intervention. Bleeding risk should be proactively managed throughout the hospital stay and during recovery. Close follow up with oncology or primary care post-discharge is essential to monitor and prevent post-hospitalization complications.
I do see that this particular case study is retrospective, and there are issues with interpretation given that situation.
What might be useful, though, is to look at a bit of history.
Armand Trousseau — A Man Who Came Up With a Diagnosis For His Own Cause of Death
Armand Trousseau was a French internist, born in 1801 and active in French politics after the revolution(s) of 1848. It was an active time in the development of medicine — Trousseau became known for the quip, “Use new drugs quickly, while they still work.” (… though, I assume, in some version in French. I cannot find the original.)
One of the many medical observations he became known for was the Trousseau sign of malignancy:
The Trousseau sign of malignancy or Trousseau's syndrome is a medical sign involving episodes of vessel inflammation due to blood clot (thrombophlebitis) which are recurrent or appearing in different locations over time (thrombophlebitis migrans or migratory thrombophlebitis). The location of the clot is tender and the clot can be felt as a nodule under the skin.[1] Trousseau's syndrome is a rare variant of venous thrombosis that is characterized by recurrent, migratory thrombosis in superficial veins and in uncommon sites, such as the chest wall and arms. This syndrome is particularly associated with pancreatic, gastric and lung cancer and Trousseau's syndrome can be an early sign of cancer[2][3] sometimes appearing months to years before the tumor would be otherwise detected.[4]
Obviously, given the time, there were no noninvasive ways to discover cancerous tumors. In fact, many times, many cancerous tumors were found after death.
Looking at Trousseau’s history of items attributed to him, he must have been an observant man who kept very good records.
Armand Trousseau first described this finding in the 1860s; he later found the same sign in himself, was subsequently diagnosed with gastric cancer and died soon thereafter.[6] Trousseau presciently attributed thromboembolism in malignancy to changes in blood composition rather than local inflammatory or mechanical forces. By correlating clinical observation with surgical and autopsy findings, Trousseau recognized that a localized cancer could induce a generalized hypercoagulable state in which thrombosis could occur elsewhere in the body, such as in extremities with visceral malignancy.
I want to say something in passing.
“Gastric cancer,” aka stomach cancer, is one of those conditions I noticed as occurring quite often among notable 19th-century men. James Clerk Maxwell, the famous physicist, died from stomach cancer at the age of 48 in 1879 (his mother had died at age 48 as well… from the same cancer.)
Armand Trousseau Diagnoses His Own Cancer
Let me get away from Wikipedia and use some different sources:
2019 Jan 31, Cancer: The History of Armand Trousseau and Cancer-Associated Thrombosis
“Je suis perdu; une phlegmatia qui vient de se déclarer cette nuit, ne me laisse aucun doute sur nature de mon mal.”
—Armand Trousseau [1]
“I am lost; a phlebitis which has declared itself this night leaves me no doubt about the nature of my illness.”
The above is what Armand Trousseau said to a colleague (and the translation into English) when he realized that the signs he saw in his own limbs meant he had cancer. He had been lecturing to crowds about his observations… and he saw the very symptoms that he had been describing to others.
In the chapter entitled “Phlegmatia Alba Dolens”, originally published in French in 1865 [7], from his most famous work, the compilation of his delivered lectures, Clinique Medicale de l’Hotel-Dieu de Paris, Trousseau discussed several detailed cases and put forth the symptom of migratory thrombophlebitis as a valuable diagnostic element of visceral cancer.
“I have long been struck with the frequency with which cancerous patients are affected with painful oedema in the superior or inferior extremities, whether one or other was the seat of cancer. This frequent concurrence of phlegmasia alba dolens with an appreciable cancerous tumor led me to the inquiry whether a relationship of cause and effect did not exist between the two, and whether the phlegmasia was not the consequence of the cancerous cachexia. I have since that period had an opportunity of observing other cases of painful oedema, in which, at the autopsy, I found visceral cancer, but in which during life, there was no appreciable cancerous tumor; and in which there existed a cachexia referable neither to the tubercular diathesis, the puerperal state, nor chlorosis. I have thus been led to the conclusion that when there is a cachectic state not attributable to the tuberculous diathesis nor to the puerperal state, there is most probably a cancerous tumor in some organ.” [8].
He also astutely observed, quite ahead of his time, that a “particular condition” in the blood, speculated to be “excess of fibrin, and an increase of white globules”, was the primary cause of thrombosis and that the change (hypercoagulable state) was also evident in many other disorders [8]. Although the first case of blood clot in cancer was noted by Jean-Baptiste Bouillaud in a publication several decades earlier [9], Bouillaud’s contribution to the field was limited, since he preferred the studies of cardiology and neurology [10]. Nevertheless, the keen observation of Bouillaud was acknowledged by Trousseau in his seminal lecture to be the basis of all venous obstruction research made in France since 1823 [8].
Trousseau retired from his prestigious post at the Faculty of Medicine and the Hôtel-Dieu de Paris (the oldest hospital in Paris) in the summer of 1866. He was tired and suffering from ill health and, as months progressed, he began to analyse his symptoms; weight loss, lack of appetite, repeated haemorrhages and stomach pains that were becoming increasingly resistant to opium [1]. For a while, he found no palpable tumour and, most importantly, no painful inflammation or oedema along the venous paths. But once he detected the missing sign he had searched for in so many of his patients, his diagnosis of gastric cancer was confirmed, and he lived for several more months in agony for its discovery, for he knew better than anyone the fatal outcome of his illness (Figure 1).
Back to Catherine
That was a little of a historical jaunt, and alas, in doing some background research I found some other links (which I will not link) that Trousseau’s signs can still be relevant for undiagnosed cancer.
But that’s enough cancer.
Let’s have some Catherine O’Hara.