Researchers found that of 168 ovarian cancer patients, there were 95 deemed to have "high social attachment" - meaning they had relationships that made them feel emotionally secure and closely connected to at least one other person.
The researchers are not sure of the reasons for the link. It seemed to go beyond practical factors, like having someone who helps you out day-to-day. But the study cannot say whether a close emotional relationship, itself, affects women's survival odds.
And a researcher not involved in the work cautioned against making too much of the findings.
It is "strictly a correlational study," said James C. Coyne, director of the behavioral oncology program at the University of Pennsylvania School of Medicine in Philadelphia, in an email.
"And," he told Reuters Health, it bears repeating that "correlations do not establish causality."
There could be various reasons for the connection between emotional support and survival, according Dr. Susan K. Lutgendorf of the University of Iowa in Iowa City, who led the new study.
"We're talking about people who feel a close connection with someone else. They feel they have someone they can confide in," Lutgendorf said.
One possibility is that women with such supportive relationships feel less stress - which, in turn, might affect their well-being in a number of ways. Based on other research, people who feel support from family and friends may stick with their medical treatment more closely, Lutgendorf noted.
But in past studies, she and her colleagues have seen some potential direct links. They've found that ovarian cancer patients' levels of "social attachment" seem to correlate with certain markers of inflammation and immune function, for instance.
Still, no one knows if close emotional relationships can actually boost women's cancer survival odds.
In fact, Coyne said, some clinical trials have looked at whether boosting social support, through support groups or psychotherapy, can extend cancer patients' lives.
"And the findings are universally negative," he said.
These latest results, reported in the Journal of Clinical Oncology, are based on 168 women who were followed from the time of surgery for their ovarian cancer. They all completed questionnaires on social support and depression symptoms.
Ninety-five women scored high enough to fall into the category of strong emotional support.
The researchers found that even when they weighed depression and other factors - like age and the stage of the cancer - emotional support, itself, was still linked to somewhat better survival.
Women who felt strong support were 13 percent less likely to die during the study period.
On the other hand, "instrumental" support was not tied to survival.