By Lisa Rapaport

(Reuters Health) – Although cancer survival rates have greatly improved in recent decades, a diagnosis with certain types of cancer can still be upsetting enough to increase a patient’s risk of suicide, a U.S. study suggests.

Researchers examined data on more than 4.6 million cancer patients, including 1,585 people who died by suicide within one year of their diagnosis. This was a suicide rate about 2.5 times higher than what would be expected in the general population, researchers report in the journal Cancer.

“For some patients with cancer, their death will ultimately not be a result of the diagnosis but rather, the emotional toll it will take on them,” said senior coauthor Dr. Hesham Hamoda of Boston Children’s Hospital and Harvard Medical School.

“There are several mechanisms that have been proposed for why a cancer diagnosis can lead to suicide for some,” Hamoda said by email. “This includes things like depression and anxiety, pain, effects of cancer treatments (fatigue), the psychological and social impacts (patients may experience fear, alienation, disfigurement), and guilty feelings about life choices that may have impacted the risk for cancer (smoking as an example).”

In the study, the suicide risk was highest in the second month after diagnosis, when cancer patients were almost five times more likely to die by suicide than people in the general population. When cancer patients were diagnosed with advanced tumors that had already spread through the body, their suicide risk was close to six times that of other people.

Suicide risk remained higher over the first six months after diagnosis, when cancer patients were more than three times as likely to die by suicide as people in the general population, the study found.

From six to 12 months after diagnosis, cancer patients were still almost twice as likely to die by suicide as other people.

The type of tumor also made a difference. People with pancreatic cancer, for example, were eight times more likely to die by suicide than other the general population, and people with lung cancer had six times the suicide risk.

Breast cancer and prostate cancer, however, didn’t appear to make a meaningful difference in suicide risk.

Most patients who died by suicide were male, white and between 64 and 84 when they were diagnosed with cancer.

Among younger patients in the study, cancer appeared to make a bigger difference in suicide risk for men than for women. Among elderly cancer patients, the opposite was true, with women experiencing greater increases in suicide risk than men.

Divorced patients also showed bigger increases in suicide risk than people who were married, single, widowed or separated.

Depression is a main cause of suicide, and one limitation of the study is that researchers didn’t know whether patients had been diagnosed with depression or anxiety. They also were unable to assess unsuccessful suicide attempts.

“The most likely reason for the increased risk in suicide after a cancer diagnosis is undiagnosed depression and anxiety,” said Dr. Alexandra Pitman, a researcher at University College London in the UK, who wasn’t involved in the study.

Some patients may become depressed or anxious as a result of the diagnosis, side effects of medications, or physical changes caused by tumors, Pitman said.

“The findings of this study are important for patients and families because they highlight the psychological problems that can affect people with cancer from quite early on in the disease, particularly for certain tumor types,” Pitman said.

But cancer patients are still less likely to die from suicide than from cancer.

“The numbers of suicide deaths in this sample are relatively low,” Pitman said. “The absolute risk of suicide in patients with cancer is low compared to their risk of other causes of death.”

SOURCE: Cancer, online January 7, 2019.