Cancer patients are more at risk of depression and suicide, research says

Years ago, when I was majoring in neurology, Dr. Corinna Seliger-Behme met a patient with end-stage bladder cancer. Before the diagnosis, he had a stable family and employment situation and no history of mental health problems, the doctor recalled. But shortly after learning of the terminal illness, he tried to kill himself with a knife in the bathtub. He spent the last week of his life in the psychiatric ward.

This patient’s situation was extreme, but for many the psychological suffering caused by cancer is great. Two studies published this Monday (28) quantify in detail the psychological burden of cancer using data sets much larger than previous research. The findings offer compelling arguments for oncologists to talk in depth with their patients about mental health difficulties.

“We can probably prevent suicide if we talk about it and if we start doing it early on,” said Seliger-Behme, a neurologist at the University of Heidelberg in Germany.

In one of the studies, she and several colleagues revisited 28 studies totaling more than 22 million cancer patients worldwide. Their analysis showed that the suicide rate among people with cancer is 85% higher than in the general population. Predictably, cancers with the best prognosis — including prostate, testicular and non-metastatic melanoma — have the lowest suicide rates. The highest suicide rates correspond to patients with worse prognosis cancers, such as stomach and pancreas.

The study found that suicide rates among people with cancer are markedly higher in the United States than in Europe, Asia or Australia. The authors speculated that the high cost of health care in the US may have led some patients to forgo treatment to avoid bankrupting their families. They also suggested that easier access to firearms in the US, compared to countries in other regions of the world, could contribute to higher suicide rates.

In the second new study, Alvina Lai, a computer science student at University College London, and a colleague created a large database compiled from the medical records of 460,000 people with 26 different types of cancer diagnosed in the UK between 1998 and 2020.

Five percent of patients were diagnosed with depression after their cancer diagnosis, and 5% were diagnosed with anxiety. About 1% of patients in this group self-harmed after diagnosis. Patients with brain tumors, prostate cancer, Hodgkins lymphoma, testicular cancer and melanoma were shown to be more prone to self-harm.

​A quarter of cancer patients had substance abuse disorder, the study found. And psychiatric problems, including substance abuse, tended to worsen over time, even years after a cancer diagnosis.

The analysis showed that the single biggest risk factor for developing a mental health problem was treatment involving surgery, radiation and chemotherapy. The duration, intensity, and cumulative side effects of this three-pronged approach may explain why it triggers depression, anxiety, and even personality disorders in many people.

Chemotherapy itself is also linked to high rates of psychiatric disorders, whose lower rates accompany so-called kinase inhibitors — targeted drugs that often cause fewer side effects.

The unambiguous data led Lai to question whether patients are given sufficient opportunities to weigh the psychological risks of possible treatments. “It would be helpful for newly diagnosed cancer patients to see what the data tells us and make an informed decision,” said Lai.

The study also pointed out surprising facts. For example, testicular cancer carries a greater risk of depression than any other type of cancer, affecting 98 out of 100 patients.

“It’s a little counterintuitive, as this is one of the best prognostic cancers,” commented Dr. Alan Valentine, director of the department of psychiatry at the MD Anderson Cancer Center in Houston, not involved in the study. For him, the discovery underscores how tumultuous a cancer diagnosis can be, even when the tumor is not deadly.

Because studies evaluating mental health often use self-reported questionnaires, the data is likely to be underrepresentative of reality, said clinical psychologist Wendy Balliet of the Hollings Cancer Center at the Medical University of South Carolina in Charleston. The persistent stigma that accompanies psychiatric disorders leads many people to hide their inner difficulties, she explained. Balliet also highlighted that the complexity involved in declaring a death a suicide can also lead to underreporting of the link between cancer and suicide.

The results raise questions about the counseling and additional psychological support that could be offered to cancer patients. “It’s hard for me not to think about the conversations these patients have with their oncologists,” Balliet said.

The studies also draw attention to cancer patients with previously diagnosed psychiatric disorders, such as schizophrenia. Previous studies have shown that more of these patients die from cancer than patients who do not have these conditions. Lai’s study found that cancer patients who have schizophrenia are more likely to receive palliative care, potentially indicating that they did not receive the treatment that would have been needed soon after their cancer diagnosis.

“Cancer is an expensive disease,” said Valentine of MD Anderson, “and it’s possible that people with severe mental disorders either don’t have access to care or have a health care system that doesn’t provide the resources they need.”

Nathalie Moise, a professor of medicine at Columbia University’s Vagellos School of Physicians and Surgeons, noted that current treatment guidelines suggest that part of routine cancer care is follow-up to check for depression. “I think these studies point to the need to also check for the presence of risk of suicide and others,” she said.

“Standardizing mental health care as an integral part of total cancer care would also help a lot,” she said.

Translation by Clara Allain