Effects of Depression Treatment on Survival in Cancer Patients

Depression and cancer are closely related. Studies show, for example, that cancer patients with depression have a worse disease course than those without it, and that depression before or after diagnosis is a risk factor for cancer-related death. Depression therefore has important effects on cancer's course, treatment and quality of life. What remains unclear is whether treating depression or removing its causes positively changes survival.

• What is depression in cancer? Symptoms and treatment of depression

Whether psychiatric and psychological treatments improve cancer patients' survival has long been debated. Two notable studies published 20 years ago were clinical studiessuggesting improved survival with these treatments. However, systematic reviews could not reach a clear conclusion, finding only small effects in certain patient subgroups or at particular times after cancer diagnosis. The greatest limitations of studies to date were participants' very different psychiatric conditions and a lack of clarity about what was being treated.

Two multicenter randomized controlled studies conducted by Oxford University's Department of Psychiatry under Prof Michael Sharpe, SMaRT Oncology - 2 [500 patients with good-prognosis (moderate disease course) cancer] and SMaRT Oncology - 3 (142 patients with poor-prognosis cancer), investigated a treatment program called "Depression Care for People with Cancer." With defined content and boundaries, it involved psychiatrists, psychologists and oncology nursesworking with the person's family doctor, and included medication and psychotherapy. Compared with usual care, patients receiving this depression program had markedly lower depression, anxiety, pain and fatigue, and higher functioning and quality of life.

The Oxford research group analyzed data from SMaRT Oncology-2, involving 500 patients followed for a median of 5 years, and SMaRT Oncology -3, involving 142 patients followed for 1 year, to investigate the depression program's effect on survival. In the study published in March 2018 in The Lancet Psychiatry, SMaRT Oncology-2 had a mortality rate of 27%, and SMaRT Oncology-3 of 80% during follow-up. The depression program, previously shown to improve depression and quality of life, was found to have, in both study groups, no statistically significant survival effect .

Commenting on the findings in the same issue of the Lancet, Dr Alex Mitchell of the University of Leicester emphasized that depression's failure to alter cancer treatment effectiveness, despite its negative association with survival, could reflect inadequate research methods rather than a true lack of effect. Mitchell stressed that demonstrating an effect on mortality statistically would require a larger group (for example, 1500) followed longer (for example, 5 years), and pointed out other methodological issues.

Conclusion

Although depression accompanying cancer is known to adversely affect treatment and survival, studies so far have not demonstrated a significant survival effect from treating depression. Larger studies with longer follow-up may resolve this uncertainty. Nevertheless, even without a demonstrated survival effect, treating depression in cancer has been proved to improve quality of life through many symptoms, particularly anxiety, pain and fatigue. Recognizing and treating depression in cancer is therefore important. Quality of lifeis as valuable as life itself!

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