NEW YORK - Women are six times more likely to end up separated or divorced if they are diagnosed with cancer or multiple sclerosis than if their male partners were facing the same illness, according to a U.S. study.

The study confirmed earlier research of a divorce or separation rate among cancer patients of 11.6 percent, similar to the general population, but found the rate jumped to 20.8 percent when the woman was sick versus 2.9 percent when the man was ill.

"Female gender was the strongest predictor of separation or divorce in each of the patient groups we studied," said Marc Chamberlain, director of the neuro-oncology program at the Seattle Cancer Care Alliance (SCCA).

The researchers said the reason men leave a sick spouse can be partly explained by their inability to rapidly adjust to becoming a caregiver and to look after the home and family.

The study also found links between age and length of marriage and the likelihood of divorce or separation. Longer marriages were likely to remain more stable but the older the woman, the more likely the partnership would end.

The study, conducted with the Huntsman Cancer Institute at the University of Utah School of Medicine and Stanford University School of Medicine, was based on following 515 patients from 2001 and 2002 until 2006.

The patients were divided into three diagnostic groups: those with a malignant primary brain tumor, those with a solid tumor with no central nervous system involvement, and those with multiple sclerosis. Almost half of the patients were women.

Chamberlain said the study was initiated because doctors noticed that in their neuro-oncology practices, divorce occurred almost exclusively when the wife was the patient, but in all cases the woman was more likely to end up alone.

Researchers also looked at the quality of life among the patients who separated or divorced.

They found these patients used more anti-depressants, took part less in clinical trials, had more frequent hospitalizations, were less likely to complete radiation therapy and more likely not to die at home.

The researchers said in the study to be published in the journal Cancer that medical providers be sensitive to possible marital discord in couples affected by a serious medical illness, especially when the woman is the affected spouse.

"Early identification and psychosocial intervention might reduce the frequency of divorce and separation, and in turn improve quality of life and quality of care," they said.