A Pilot Study to Evaluate Individualized Choice of Antidepressant in Patients With Cancer

Trial Information

A Pilot Study to Evaluate Individualized Choice of Antidepressant in Patients With Cancer

Major depressive disorder (MDD) is a debilitating illness associated with increased
mortality and significant impairment in quality of life. The prevalence of MDD is
particularly high in patients with cancer, as much as 38% in some studies.

The study of depression in cancer patients is particularly important, as these co-morbid
illnesses can frequently complicate the management of each other. In addition to affecting
quality of life, poorly controlled depression can affect cancer treatment adherence and can
lead to poor treatment outcomes.

Depression can be challenging to diagnose in patients with cancer. A spectrum of depressive
symptoms can be seen, ranging from appropriate sadness in response to a life threatening
diagnosis, to a major depressive episode. The diagnosis is confounded by the symptoms
brought on by the cancer and its treatment, such as fatigue, insomnia, anorexia, and pain.
Medications commonly used in cancer patients such as narcotics, benzodiazepines,
antihistamines, steroids, antibiotics, chemotherapy, and endocrine therapy can all lead to
side effects that further confuse the picture. However, while challenging, evidence does
suggest that a valid diagnosis of depression can be made in this patient population.

The current standard for diagnosing MDD is the Diagnostic and Statistical Manual of Mental
Disorders - Fourth Edition - Text Revision (DSM-IV-TR), which was published in 2000 by the
American Psychiatric Association. The diagnosis is made based on an interview between the
patient and physician in which nine criteria are assessed, including depressed mood,
anhedonia, weight loss or gain, insomnia or hypersomnia, psychomotor agitation or
retardation, fatigue, feelings of worthlessness or guilt, difficulty concentrating, and
recurrent thoughts of death. In patients with cancer, the diagnosis of MDD is more often
based on anhedonia and feelings of worthlessness, as depressed mood, weight fluctuation, and
sleep disturbance can be symptoms of the underlying cancer itself. Once the diagnosis has
been made, there are several tools which have been created and validated for the purpose of
assessing the severity of depression and for following the severity over time. The tool we
intend to use in this study is the PHQ-9.

Therapy for MDD in the general population includes both psychotherapy and pharmacological
intervention. However, the optimal therapy of MDD in cancer patients remains uncertain.
Very few placebo controlled trials have been performed in this population, and there is
currently no uniformly accepted standard of care. Some of the evidence from studies in
depressed but otherwise medically healthy patients may be applicable to cancer patients, but
there are several factors which complicate the treatment of depression in this group. For
example, the overlap of symptoms between depression and the underlying malignancy can
confound the diagnosis, as discussed earlier. Simultaneous treatment of the underlying
malignancy introduces adverse effects from surgery, chemotherapy, or radiation, as well as
an increased likelihood of drug-drug interactions. Finally, co-morbid conditions such as
cancer pain can contribute to the depression, requiring simultaneous therapy. As a result
of these unique factors, the treatment of MDD in cancer patients cannot necessarily be
approached using the standard recommendations for the general population.

There is scant evidence supporting the effectiveness of pharmacologic therapy in cancer
patients with MDD. In the last 25 years only four placebo controlled trials have been
published, and of these only two have shown a statistically significant improvement in
depression scores with active treatment.

Additional studies are needed to evaluate some of the newer antidepressants within the
cancer population and to assess whether this strategy of matching side effects to symptoms
is beneficial.