When Antidepressants Are Needed in Oncology: Benefits and Side Effects

Cancer treatment may bring psychological as well as physical difficulties. Treatment should be planned with the whole person in mind. Antidepressants may therefore be a necessary part of treatment for cancer patients struggling psychologically. This article reviews important clinical studies and data from the past 30 years to explain antidepressants’ role in cancer care.

Emotional distress and anxiety affect 40-60% of cancer patients

Among these conditions, adjustment and stress-related disorders and major depression are the most common in oncology and have supported treatments. Antidepressants aim to reduce patients’ depressive symptoms and improve their quality of life .

Antidepressants have two main benefits in cancer treatment:

1.  Reducing or eliminating the severity of distressing psychological conditions such as stress, anxiety and depression 
2. Treating hot flashes, neuropathic pain, nausea, vomiting and itching caused by treatment.

The research presented summarizes important studies of antidepressant use in cancer, beginning in 1997 and ending in 2017.

Antidepressant characteristics and mechanisms of action

There are 4 classes of antidepressants with different mechanisms. First-class drugs such as monoamine oxidase inhibitors can treat some resistant depression types but are not preferred in oncology because of interactions with strong painkillers (opioids). Other first-class drugs, such as tricyclic antidepressants, are also generally avoided because they may cause many side effects in cancer patients, such as anticholinergic effects.

Over the past decade, second- and third-generation antidepressants with fewer side effects have been widely preferred in oncology. Recently introduced fourth-generation drugs, such as agomelatine and vortioxetine, have limited and incomplete oncology experience. Other agents, such as psychostimulants and hallucinogens, are classified and described separately.

The Most Commonly Preferred Antidepressant Group in Oncology: Selective Serotonin Reuptake Inhibitors - SSRIs

These are first-choice antidepressants for depression in cancer patients. They increase serotonin, called the happiness hormone, in the brain. Remember that some SSRIs, such as fluoxetine and paroxetine, may interact with cancer treatments. The most commonly preferred SSRIs in oncology, with the fewest drug interactions, are sertraline, citalopram and escitalopram.

Clinical use of antidepressants for psychological conditions

Depression

Depressive disorders are two to three times more common in cancer patients than in the general population. Treating depression in cancer patients with antidepressants has been found more effective than placebo. Depression is also treated according to severity, such as mild-to-moderate or major depression.

Stress-related disorders

Stress and related disorders, including acute stress disorder, post-traumatic stress disorder (PTSD) and adjustment disorders, are common in cancer patients. Clinical trials of antidepressants for PTSD suggest selective serotonin reuptake inhibitors are effective.

Anxiety disorders

For anxiety disorders in cancer patients—serious persistent fears including phobias, chemotherapy, nausea, vomiting and social anxiety—selective serotonin reuptake inhibitors and serotonin-norepinephrine reuptake inhibitors are preferred.

- Related Topic: What is anxiety? Symptoms and treatment of anxiety in cancer

Sleep disorders

Sleep/wake cycle disorders are common in cancer patients as part of depression, stress-related conditions or anxiety disorders and should be appropriately addressed. In addition to hypnotics, usually benzodiazepines, antidepressants with sedating components, such as mirtazapine and trazodone, may help.

- Related Topic: Sleep problems affect learning - What is good-quality sleep, and how can you sleep well?

Other cancer-related symptoms

Evidence-based clinical practice suggests antidepressants may be used for poor appetite, sleep disorders, pain, anxiety and fatigue and other nonpsychiatric cancer-related symptoms, improving quality of life.

Pain

Pain is among cancer patients’ most distressing problems. The European Society for Medical Oncology (ESMO) cancer pain guidelines recommend antidepressants as adjuvant pain treatment. Serotonin-norepinephrine reuptake inhibitors (venlafaxine and duloxetine) are suggested to be effective in the chemotherapy treatment of neuropathic pain in cancer patients.

- Related Topic: How is cancer pain treated?

Hot flashes

Hot flashes are common during or after treatment of hormone-sensitive cancers such as breast and prostate cancer. Venlafaxine is the most commonly preferred antidepressant for them, but selection and use require caution: effectiveness is uncertain and antidepressants themselves have reported side effects. For hot flashes caused by cancer treatment, acupuncture appears an effective and safer method.

Appetite and nausea / vomiting

Antidepressants benefit appetite, nausea and vomiting. A phase II clinical trial confirmed positive effects on appetite, sleep disorders, anxiety, pain and quality of life, as well as benefits for depression in cancer patients.

Fatigue

Fatigue is common in cancer patients. The norepinephrine-dopamine reuptake inhibitor antidepressant bupropion has been proposed to reduce cancer-related fatigue through dopaminergic activity.

- Related Topic: Can weakness and fatigue be the first sign of cancer?

In conclusion, antidepressants have been shown effective for treating severe depression and other cancer-related problems. They are safe and effective for severe depression in cancer patients. However, limitations and general cautions must be considered. Research into their effects on major and persistent depression continues, taking different cancer types into account, and recommendations should be followed.