
- Vol 40, Issue 4
A Case of Clozapine and Cancer
What does cancer treatment mean for psychiatric treatment with clozapine?
SPECIAL REPORT: SCHIZOPHRENIA
Early in my career, I first started noticing a trend among some of my patients with schizophrenia who were treated with
Sadly, however, my hypothesis was confirmed years later by a nationwide case-control and cohort study conducted in Finland.1 The study was constructed by “individually matching cases of lymphoid and haematopoietic tissue malignancy with up to 10 controls without cancer by age, sex, and time since first schizophrenia diagnosis,” but ethnicity data were not available or included. Analysis was conducted using conditional logistic regression (adjusting for comorbid conditions) and the study demonstrated a 2.7-fold increased risk of hematological malignancies with clozapine use (dose-dependent) compared with exposure to other antipsychotics.1 According to the Centers for Disease Control and Prevention, lymphoma, myeloma, and leukemia are all common types of hematological malignancies.2
I still remember my first patient’s
As we know, clozapine treatment is not considered a first-line treatment in
Now that they were diagnosed with
I reached out to the Risk Evaluation and Mitigation Strategy (REMS) safety program, which was instituted by the FDA to enforce safety monitoring for the potential risk of severe neutropenia (absolute neutrophil count [ANC] less than 500/µL) associated with clozapine.5 I thought that because REMS is the gatekeeper for the medication to be dispensed, then of all organizations, surely it would be able to offer some guidance. The American Society of Clinical Oncology indicates that chemotherapy can result in neutropenia 7 to 12 days after treatment.6
The REMS program had to be aware of this fact and would have some guidance for psychiatric clinicians, right? Wrong. I was met with silence.
A literature search through my local hospital yielded sparse and inconsistent information as well. I turned to my colleagues, who gave me the best advice and support they could, but it was ultimately my patient and my decision. After discussing the risks and benefits with the patient and their caregiver, we decided to attempt to continue
The oncologist turned out to be a brilliant clinician who was very receptive to coordinating care to work toward the most optimal outcome for our mutual patient. Our now shared client was in the maintenance phase of clozapine treatment, meaning that their ANC was now required to be drawn only monthly to be entered into the REMS program. That was all about to change.
When the patient started cancer treatment, their ANC level began to decline. The oncologist’s office was drawing labs frequently throughout chemotherapy, and now, because of neutropenia, we needed additional labs. Each of our offices began drawing ANC levels as clinically indicated and exchanging this information as rapidly as possible. The patient never went more than 2 weeks without labs throughout their entire cancer treatment. I frequently met with the patient and updated them and their caregiver on the ANC lab values between appointments.
Ultimately, even though neutropenia did occur, it did not become severe enough to require the discontinuation of clozapine. The patient remained psychiatrically stable throughout their cancer treatments, and after several rounds of chemotherapy, our patient’s cancer was treated to remission.
Since that time, further research has concluded that “It is possible to continue clozapine in a patient with chronic schizophrenia undergoing chemoradiation for cancer with close supervision and collaboration with oncology clinicians.”7 I can confirm this finding now from my clinical experiences over the years as well. I have yet to take anyone off clozapine therapy because of the impacts of their cancer treatments.
So what does a cancer diagnosis and treatment mean for patients with schizophrenia who are currently being treated with clozapine? It means I am going to work even harder to collaborate with other clinicians, frequently monitor my patients, and continue to do my part in helping them navigate the complexities of 2 difficult diagnoses.
As far as my use of clozapine, I will continue utilizing it until it is no longer in a patient’s best interest, and I will certainly continue to educate my patients on the risks of not only agranulocytosis, but also cancer (no matter how small the risk may be).
Mr Hickman is a psychiatric mental health nurse practitioner on the seacoast of New Hampshire.
References
1. Tiihonen J, Tanskanen A, Bell JS, et al.
2. Hematologic cancer incidence, survival, and prevalence. Centers for Disease Control and Prevention. Reviewed September 1, 2022. Accessed February 1, 2023.
3. Survival rates and factors that affect prognosis (outlook) for non-Hodgkin lymphoma. American Cancer Society. Updated March 2, 2022. Accessed February 1, 2023.
4. Information on clozapine. US Food and Drug Administration. Updated November 2, 2022. Accessed February 1, 2023.
5. What is the Clozapine REMS? Clozapine REMS. Accessed February 1, 2023.
6. Neutropenia. Cancer.Net. September 2019. Accessed February 1, 2023.
7. Deodhar JK, Prabhash K, Agarwal JP, Chaturvedi P.
Articles in this issue
over 2 years ago
The Border Zone Between bvFTD and Primary Psychiatric Disordersover 2 years ago
On the Convergence of Science and Clinical Practiceover 2 years ago
Role of Lithium in 2023 in Bipolar I Mania and Depressionover 2 years ago
Professional Courtesy: Guidelines for Physiciansover 2 years ago
Exploring the Biocognitive Modelover 2 years ago
Toolsover 2 years ago
Co-occurring Substance Use and Eating Disordersover 2 years ago
Yes, It’s All in Your HeadNewsletter
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