The overall incidence of suicide is low among cancer patients but they are twice to 2½ times more apt to take their own life than members of the general population, an oncologist in Ottawa says.

Dr. Wayne Kendal, a radiation oncologist at the Ottawa Hospital Regional Cancer Centre, came to the conclusion after analyzing 1.3 million cancer cases in the U.S.

"We must get the message out to physicians, nurses and social workers that they should be aware of the potential for suicide in their cancer patients," said Kendal. "Maybe, by giving people in need, and their families, more support and providing better symptom control we might be able to foster the desire to continue living."

A high-risk patient might be a white male, with a new diagnosis of head and neck cancer or myeloma, widowed, with advanced stage cancer, a history of other cancers and poor social support, the study suggested.

Conclusions about risk factors can only be speculative, Kendal cautioned.

It could be that patients feel hopeless when surgery or radiotherapy are not considered appropriate. In cancers of the head and neck, pain and difficulty feeding may be factors. Chronic pain, weakened bones and fractures are more common in myeloma, so quality of life issues could be playing a role, he said.

In contrast, a female of African-American heritage with breast or colorectal cancer who lives with her spouse showed a lower risk, according to the study in Thursday's online issue of the Annals of Oncology.

Risk higher for more advanced disease

Of the cases studied, 265 females and 1,307 males committed suicide, which works out to a suicide rate of roughly 19 out of every 1,000 male cancer patients and about four out of every 1,000 female patients.

The overall rate of suicide is about 24 per 100,000 cancer patients per year, compared with 10.6 per 100,000 for the general U.S. population.

Male cancer patients were nearly five times more likely to commit suicide than female patients, which matches the male-female suicide ratio in the general U.S. population.

Suicide risk was higher for cancers of the lungs and bronchus, bladder, head and neck, esophagus and myeloma.

Both men and women were more likely to commit suicide if the cancer had already spread at the time of diagnosis.

Other findings included:

• Males with lung, liver and brain cancer or leukemia had lower rates of suicide than males with other types of cancer.
• For men, the suicide rate peaked right after diagnosis, while the rate stayed about the same over time for women.
• The suicide risk for men was more than halved if they were married. For married women, it was about a third lower.
• Blacks had a lower risk of suicide, as is the case in the general U.S. population.
• Refusing surgery or radiation did not appear to increase risk, but there was a higher risk of suicide when doctors discouraged surgery, such as in more advanced cases.