TUESDAY, Aug. 12 (HealthDay News) -- Cancer patients are at increased risk for suicide, according to three new studies.

In the first study, researchers at the University of Washington analyzed U.S. data from 1973 to 2002 and found that the suicide rate among cancer patients was 31.4 per 100,000 person-years, compared to 16.7 per 100,000 person-years in the general population.

Higher suicide rates were associated being male, white and older at the time of cancer diagnosis. Patients with the highest suicide rates were those with lung, stomach, oral/pharyngeal and larynx cancers. Suicide risk was greatest within the first five years after diagnosis but remained elevated for up to 15 years after diagnosis.

The second study found that older Americans with cancer are more than twice as likely to commit suicide as those without cancer. The Harvard School of Public Health and Harvard Medical School study compared 128 New Jersey residents, age 65 and older, who committed suicide between 1994 and 2002 and 1,280 living people in the same age group.

The suicide risk was 2.3 times higher among cancer patients than among those who were cancer-free. This increased risk held true even after the researchers adjusted for age, sex, race, medical and psychiatric illnesses, and use of prescription medications.

The cancer patients in the study who committed suicide were more likely to have advanced metastatic disease, and two-thirds of them used a firearm to commit suicide. Most of the patients who committed suicide had seen a physician in the month before their death, and 25 percent had seen a doctor within a week before their suicide.

A third study by researchers at the University of Edinburgh in the United Kingdom found that cancer patients are at increased risk for suicidal thoughts. The survey of 2,924 cancer patients receiving outpatient care found that nearly 8 percent reported suicidal thoughts persisted for at least several days over the previous two weeks. A similar survey of the general population in Australia found that only 2.6 percent of respondents reported having similar thoughts.

The University of Edinburgh team found that suicidal thoughts among cancer patients were associated with having substantial emotional distress or pain, but not with cancer severity. Better management of patients' emotional distress and pain may improve quality of life and reduce suicide risk, the researchers concluded.

The research was published online Monday in the Journal of Clinical Oncology.

More attention needs to be given to suicidal thoughts and attempts by cancer patients, Dr. Timothy Quill, a professor of medicine, psychiatry and medical humanities at the University of Rochester Medial Center, said in an accompanying editorial.

"It is important to ask about suicidal thoughts regularly, especially when disease is worsening, symptoms are increasing, or the patient is entering a more serious phase of illness ... Creating an environment where these issues can be openly explored without being judged is critical," Quill wrote.

More information

The American Cancer Society has more about cancer and depression.