Source: www.medscape.com
Author: Nick Mulcahy

Depression — the most extensively studied mood complication associated with cancer — is “less common in patients with cancer than previously thought,” according to the authors of a new meta-analysis.

“Substantial uncertainty exists about prevalence of mood disorders in patients with cancer, including those in oncological, hematological, and palliative-care settings,” write the authors, led by Alex Mitchell, MRCPsych, from the Department of Cancer Studies and Molecular Medicine at the Leicester Royal Infirmary and Leicestershire Partnership Trust, in the United Kingdom.

For instance, reviews of depression in palliative-care cancer settings have shown prevalences between 1% and 69%, say the authors.

However, the meta-analysis found that depression affects only about 16% of patients in oncological, hematological, and palliative-care settings.

This rate is “modest,” and suggests that “depression is not an invariable complication of cancer,” write the authors. The analysis was published online January 19 in the Lancet Oncology.

But depression is only one problem. “Some combination of mood disorders” occurs in 30% to 40% of cancer patients in these 3 hospital settings, the authors report. The study’s take-away message is that clinicians should remain “vigilant for mood complications, not just depression,” suggest Dr. Mitchell and colleagues.

They also recommend that clinicians use simplified screening tools to look out for “distress, activities of daily living, quality of life, unmet needs, and desire for help.”

Herein lies the great challenge, suggested an expert not involved with the meta-analysis — namely, how to proceed in the cancer clinic with patients who are depressed and/or have mood disorders.

“Regular screening using a simple tool is very useful. However, this is only true when there is a system in place for referral of patients for further assessment and management,” said Eduardo Bruera, MD, chair of the Department of Palliative Care and Rehabilitation Medicine at the University of Texas M.D. Anderson Cancer Center in Houston.

“The busy oncology setting cannot easily provide emotional interdisciplinary care for these patients,” Dr. Bruera told Medscape Medical News.

Cancer centers are generally exceptions to this limitation, Dr. Bruera explained. “At M.D. Anderson, most patients undergo some form of screening. All patients referred to supportive/palliative care undergo assessment of anxiety and depression using the [Edmonton Symptom Assessment Scale]. This is a very simple patient-completed tool capable of providing a graphic display of multiple physical and emotional symptoms in a minute or 2,” he said.

Thus, at many cancer centers, cancer patients can potentially be treated for depression and other mood disorders in the context of their cancer care, said Dr. Bruera.

“Supportive and palliative-care teams are able to work alongside medical oncologists in most cancer centers to help patients express their maximum physical and emotional function during and after the completion of cancer treatment,” he said.

Study Findings
In cancer settings, depression has serious consequences, write the authors. Studies indicate that it reduces participation in medical care, prolongs hospital stays, and significantly affects quality of life and survival, they point out.

Still, “despite many years of research, prevalence of depression in patients with cancer is still subject to much debate,” according to Dr. Mitchell and colleagues.

So the investigators set out to do a high-quality review of the literature and included studies with data for the prevalence of depression and related mood disorder in adults with cancer in hospital settings.

The review, which involved more than 14,000 patients, is the best to date, say the authors. “Although several informative systematic reviews have been published, no previous studies have quantitatively analyzed such a robust dataset of mood disorders in cancer settings,” they claim.

Using definitions supplied by either the Diagnostic and Statistical Manual of Mental Disorders (DSM) or the International Classification of Diseases (ICD), they sought out studies on syndromal (clinical) depression, defined by formal interview; major and minor depressions, defined by interview against DSM research criteria (minor depression is listed in the DSM-IV text revision under depressive disorder not otherwise specified); dysthymia; adjustment disorder (either alone or in combination with depression); anxiety disorders; and combined mood disorders.

They identified 433 relevant articles, of which 94 were ultimately eligible for review (24 in palliative-care and 70 in nonpalliative-care settings) and involved patient data from the first 5 years after cancer diagnosis.

In palliative-care settings, the meta-analytical pooled prevalence of depression was 16.5%; of major depression was 14.3%; and of minor depression was 9.6%. The prevalence of adjustment disorder alone was 15.4% and of anxiety disorders was 9.8%. The prevalence of all types of mood disorder was 29.0%.

In oncological and hematological settings, the prevalence of depression was 16.3%; of major depression was 14.9%; and of minor depression was 19.2%. The prevalence of adjustment disorder was 19.4%, of anxiety was 10.3%, and of dysthymia was 2.7%. Combination diagnoses were common, including a prevalence of all types of mood disorder of 38.2%.

Across all studies, there were “modest rates of syndromal depression” in patients with cancer, say the authors. Depression is only common when all subtypes and related mood disorders are combined, they add.

The investigators, noting that there was no significant difference in rates of depression and anxiety between palliative and nonpalliative settings, also say that the effect on depression of the cancer setting and the stage of cancer might be overemphasized.

Despite their findings, the authors note that cancer patients with depression still amount to a large group of individuals. They estimate that 340,000 people in the United Kingdom and 2 million in the United States have “major depression and cancer at any time.”

The authors have disclosed no relevant financial relationships.

Source: Lancet Oncol. Published online January 19, 2011.